Air-Cooled Screw Compressor Chiller · 2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit unless extra clearance is provided

Installation, Operation and Maintenance Manual IOMM ALS-3

Group: Chiller

Part Number: 330145707

Date: March 2001

Supersedes: IOMM ALS-2

Air-Cooled Screw Compressor Chiller

ALS 141C through 420C

60 Hertz

2 IOMM ALS-3

Table Of Contents

Introduction............................. 3General Description ........................................ 3Nomenclature................................................... 3Inspection ........................................................ 3

Installation and Start-up............ 3Handling........................................................... 4Location............................................................ 5Service Access................................................ 5Clearance Requirements................................. 6Vibration Isolators........................................... 9Lifting and Mounting Weights ................... 10Water Piping .................................................. 12System Water Volume ................................... 13Variable Water Flow...................................... 13Evaporator Freeze Protection...................... 14Flow Switch.................................................... 14Water Connections....................................... 15Refrigerant Charge........................................ 15Glycol Solutions............................................ 15

Remote Evaporator................ 16General............................................................ 16Performance Derate Factors ........................ 16Refrigerant Piping ......................................... 17Startup Procedures ....................................... 22Dimensions, Remote Evaporator................ 23

Water Flow and Pressure Drop26

Physical Data......................... 28

Compressor Staging .............. 32

Dimensional Data................... 34

Wind Baffles and Hail Guards 37

Electrical Data........................ 39Field Wiring.................................................... 39Wire Sizing Ampacities ................................ 40

Field Wiring Diagram ............. 59

Solid State Starters ................ 60

Unit Layout and Principles ofOperation.............................. 67

Major Component Location.........................67Control Center................................................68Sequence of Operation.................................71

Start-up and Shutdown .......... 73Seasonal Start-up ..........................................73Temporary Shutdown ...................................73Start-up After Temporary Shutdown..........74Extended (Seasonal) Shutdown ..................74Start-up After Extended (Seasonal)Shutdown .......................................................75

System Maintenance.............. 76General............................................................76Compressor Maintenance............................76Lubrication .....................................................76Electrical Terminals ........................................76Condensers ....................................................76Refrigerant Sightglass ..................................77Lead-Lag.........................................................77Preventative Maintenance Schedule..........78

Service.................................. 79Compressor Solenoids..................................79Filter-Driers.....................................................79Liquid Line Solenoid Valve ..........................81Electronic Expansion Valve..........................81Electronic Expansion Valve Operation .......82Evaporator......................................................82Charging Refrigerant.....................................83Charging Oil ...................................................84

In-Warranty Return MaterialProcedure ............................. 85

Standard Controls ................. 86Optional Controls ..........................................91Controls, Settings and Functions...............92Troubleshooting Chart .................................93Periodic Maintenance Log...........................94

Our facility is ISO CertifiedInitial Issue January 1998

"McQuay" is a registered trademarks of McQuay International2001 McQuay International

"Information covers the McQuay International products at the time of publication and we reserve the right to make changes indesign and construction at anytime without notice"

IOMM ALS-3 3

Introduction

General DescriptionMcQuay air-cooled water chillers are complete, self-contained automatic refrigerating units thatinclude the latest in engineering components arranged to provide a compact and efficient unit. Eachunit is completely assembled, factory wired, evacuated, charged, tested and comes complete andready for installation, except for remote evaporator models. Each unit consists of multiple air-cooledcondensers with integral subcooler sections, multiple accessible semi-hermetic single-screwcompressors, solid-state starters, multiple circuit shell-and-tube evaporator, and complete refrigerantpiping. Liquid line components included are manual liquid line shutoff valves, charging valves, filter-driers, liquid line solenoid valves, sightglass/moisture indicators, and electronic expansion valves.Compressor suction and discharge shutoff valves are included. Other features include compressorheaters, an evaporator heater for low ambient water freeze protection, automatic one time pumpdownof refrigerant circuit upon circuit shutdown, and an advanced fully integrated microprocessor controlsystem.

Nomenclature

A L S - XXX C

InspectionWhen the equipment is received, all items should be carefully checked against the bill of lading toinsure a complete shipment. All units should be carefully inspected for damage upon arrival. Allshipping damage must be reported to the carrier and a claim must be filed with the carrier. The unit’sserial plate should be checked before unloading the unit to be sure that it agrees with the powersupply available. Physical damage to unit after acceptance is not the responsibility of McQuayInternational.Note: Unit shipping and operating weights are available in the Physical Data Tables.

Installation and Start-up

Note: Installation and maintenance are to be performed only by qualified personnel who are familiarwith local codes and regulations, and experienced with this type of equipment.

CAUTIONSharp edges and coil surfaces are a potential injury hazard. Avoid contact with them.

Start-up by McQuayService is included on all units sold for installation within the USA and Canadaand must be performed by them. Two week prior notification of start-up is required. The contractorshould obtain a copy of the Start-up Scheduled Request Form from the sales representative or fromthe nearest office of McQuayService.

Air-Cooled

Liquid Oil Injected

Rotary Screw Compressor

Design Vintage

Nominal Tons

4 IOMM ALS-3

HandlingCare should be taken to avoid rough handling or shock due to impact or dropping the unit. Do notpush or pull the unit from anything other than the base, and block the pushing vehicle away from theunit to prevent damage to the sheet metal cabinet and end frame (see Figure 1).

Never allow any part of the unit to fall during unloading or moving as this may result in seriousdamage.

To lift the unit, 2½ “ (64 mm) diameter lifting holes are provided in the base of the unit. Spreader barsand cables should be arranged to prevent damage to the condenser coils or unit cabinet (see Figure 2).

Figure 1, Suggested Pushing Method

Figure 2, Required Lifting Method

NOTES:1. All rigging points on a unit, either 4, 6, or 8 locations, must be used. See Figure 7 through Figure 10 for number,

location, and weight at lifting points for a specific size unit. This diagram illustrates a unit with 4 mounting holes(ALS 141 - ALS 218).

2. Crosswise and lengthwise spreader bars must be used to avoid damage to unit. Lifting cables from the unitmounting holes up must be vertical.

3. The number of condenser sections, and fans can vary from this diagram.

IOMM ALS-3 5

LocationCare should be taken in the location of the unit to provide proper airflow to the condenser. (SeeFigure 3 through Figure 5 for required clearances).

Due to the vertical condenser coil design of the ALS chillers, it is recommended that the unit beoriented so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect oncondensing pressure and performance. It is recommended that wind baffles be installed if the unit isinstalled with no protection against prevailing winds.

Using less clearances than shown in Figure 3, Figure 4, and Figure 5 will cause discharge airrecirculation to the condenser and could have a significant and detrimental effect on unit performance.See the current version of McQuay Product Manual PM ALS for more detailed information on thesubject of air recirculation.

Service AccessEach end of the unit must be accessible after installation for periodic service work. Compressors,filter-driers, and manual liquid line shutoff valves are accessible on each side of the unit adjacent tothe control box. High pressure and low pressure transducers are mounted on the compressor. Thecooler barrel heater thermostat is located on the cooler. Compressor microprocessor and most otheroperational and equipment protection controls are located in the unit control box. The solid-statestarters with their internal electrical protection features are mounted on the base side rails adjacent tothe compressor they serve.

On all ALS units the condenser fans and motors can be removed from the top of the unit. Thecomplete fan/motor assembly can be removed for service. The fan blade and fan motor rain shieldmust be removed for access to wiring terminals at the top of the motor.

WARNINGDisconnect all power to the unit while servicing condenser fan motors.

Failure to do so may cause bodily injury or death.

Do not block access to the sides or ends of the unit with piping or conduit. These areas must be openfor service access. Do not block any access to the control panel with a field mounted disconnectswitch.

6 IOMM ALS-3

Clearance RequirementsFigure 3, Clearance Requirements, ALS 141-218

Notes:

1. Minimum side clearance between two units is 12 feet.

2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unitunless extra clearance is provided per note 4.

3. Minimum clearance on each side is 8 feet when installed in a pit no deeper than the unit height.

4. Minimum side clearance to a side wall or building taller than the unit height is 8 feet provided nosolid wall above 6 feet is closer than 12 feet to the opposite side of the unit.

5. The evaporator can be removed from the side of the unit.

6. Do not mount electrical conduits, etc, above the side rail on either side if the unit.

7. There must be no obstruction of the fan discharge.

8. It is recommended that field supplied disconnect switches not be mounted on the unit.

IOMM ALS-3 7

Figure 4, Clearance Requirements, ALS 245-295

Notes:





5. The evaporator can be removed from the side of the unit.




8 IOMM ALS-3

Figure 5, Clearance Requirements, ALS 325-420

Notes:





5. The removable post for compressor service access must not be blocked at either side of the unit.




IOMM ALS-3 9

Vibration IsolatorsVibration isolators are recommended for all roof mounted installations or wherever vibrationtransmission is a consideration. The following section "Lifting and Mounting Weights" contains thelocation of unit lifting holes and the load at each location. Mounting holes are also dimensioned andthe bearing weight at each hole given.

Figure 6, Spring Flex Isolators

Table 1, Spring Vibration Isolators, Part NumbersMounting Location (See Footprint Drawings Figure 7 through Figure 10)

Model R1 R2 R3 R4 R5 R6 R7 R8 R9 R10ALS 141-ALS 186 Isolator kit part number 350014880

Max Load 2200 2200 2600 2600 1800 1800Spring P/N 022611901 022611901 022612000 02261200 022611800 022611800

Color Gray Gray White White Green GreenHousing P/N 022610300 022610300 022610300 022610300 022610300 022610300

ALS 190-ALS218 Isolator kit part number 350014881Max Load 2600 2600 3000 3000 2200 2200

Spring P/N 022612000 022612000 330202101 330202101 022611901 022611901Color White White Gold Gold Gray Gray

Housing P/N 022610300 022610300 022610300 022610300 022610300 022610300

ALS 245-ALS 295 Isolator kit part number 350014882Max Load 2200 2200 3000 3000 2600 3000 1800 2200

Spring P/N 022611901 022611901 330202101 330202101 022612000 330202101 022611800 022611901Color Gray Gray Gold Gold White Gold Green Gray

Housing P/N 022610300 022610300 022610300 022610300 022610300 022610300 022610300 022610300

ALS 325-ALS 420 Isolator kit part number 350014883Max Load 2600 2600 3000 3000 2200 2200 3000 3000 2600 2600

Spring P/N 022612000 022612000 330202101 330202101 022611901 022611901 330202101 330202101 022612000 022612000Color White White Gold Gold Gray Gray Gold Gold White White

Housing P/N 022610300 022610300 022610300 022610300 022610300 022610300 022610300 022610300 022610300 022610300Notes:1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.2. The spring is fully compressed at approximately 3900 lb. (1769 kg).

10 IOMM ALS-3

Lifting and Mounting WeightsFigure 7, ALS 141C – ALS 186C Lifting and Mounting Locations

NOTES:

1. 2 ½ in. (63.5 mm) lifting holes at location "L" on side of base rail.

2. 1 in. (25.4 mm) mounting holes at location "R" on bottom of base rail.

Lifting Weight for EachPoint lb (kg)

Mounting Loads for Each Point lb. (kg)ALS

ModelL1 & L2 L3 & L4 R1 & R2 R3 & R4 R5 & R6

Operating Wtlb. (kg)

Shipping Wt.lb. (kg)

Copper FinAdd

141 2585 (1171) 2125 (963) 1835 (831) 1785 (809) 1230 (557) 9700 (4394) 9420 (4267) 1370 (620)

150 2570 (1164) 2205 (999) 1830 (829) 1805 (818) 1305 (591) 9880 (4476) 9550 (4326) 1370 (620)

171 2570 (1164) 2210 (1001) 1830 (829) 1810 (820) 1305 (591) 9890 (4472) 9560 (4331) 1370 (620)

186 2575 (1166) 2210 (1001) 1830 (829) 1810 (820) 1310 (593) 9900 (4485) 9570 (4335) 1370 (620)

Figure 8, ALS 190C – ALS 218C Lifting and Mounting Locations

Lifting Weight for EachPoint lb (kg)

Mounting Loads for Each Point lb. (kg)ALS

ModelL1 & L2 L3 & L4 R1 & R2 R3 & R4 R5 & R6



Copper FinAdd

190 2915 (1320) 2230 (1010) 2010 (910) 2135 (967) 1165 (527) 10620 (4811) 10290 (4661) 1610 (730)

200 2920 (1323) 2230 (1010) 2015 (913) 2135 (967) 1165 (527) 10630 (4815) 10300 (4666) 1610 (730)

206 2940 (1332) 2310 (1046) 2000 (906) 2240 (1015) 1240 (562) 10960 (4965) 10500 (4756) 1610 (730)

218 2960 (1341) 2405 (1089) 1985 (899) 2425 (1098) 1365 (618) 11550 (5232) 10730 (4861) 1610 (730)

R1

R2

R3

R4

R5

R6

L1

L2

L3

L4

CO

NT

RO

L B

OX

36 (914)102 (2591)

192 (4877)

46 (1168)161 (4089)

2 (51)Typical Spacingfor IsolatorMounting (6)

83.4(2118)

L1 L3

L2 L4

R1

R2

R3

R4

R5

R6

CO

NT

RO

L B

OX

36 (914)123 (3124)

224 (5690)

46 (1168)195 (4953)


83.4(2118)

IOMM ALS-3 11


Lifting Weight for Each Point lb (kg) Mounting Loads for Each Point lb. (kg)ALSModel L1 & L2 L3 & L4 L5 L6 R1 & R2 R3 & R4 R5 & R6 R7 R8



Copper FinAdd

245 2845 (1289) 2445 (1108) 1420 (643) 2050 (928) 1745 (790) 2240 (1015) 2030 (920) 1150 (521) 1660 (752) 14840 (6722) 14030 (6356) 2020 (915)

260 2850 (1291) 2445 (1108) 1420 (643) 2050 (928) 1745 (790) 2245 (1017) 2030 (920) 1150 (521) 1660 (752) 14850 (6727) 14040 (6360) 2020 (915)

270 2845 (1289) 2455 (1112) 1430 (648) 2060 (933) 1750 (793) 2245 (1017) 2035 (922) 1155 (523) 1665 (528) 14880 (6741) 14090 (6383) 2020 (915)

275 2850 (1291) 2455 (1112) 1430 (648) 2060 (933) 1755 (793) 2245 (1017) 2035 (922) 1155 (523) 1665 (528) 14890 (6745) 14100 (6387) 2020 (915)

295 2865 (1298) 2455 (1112) 1430 (648) 2060 (933) 1755 (793) 2250 (1019) 2035 (922) 1155 (523) 1665(528) 14900 (6750) 14110 (6392) 2020 (915)


Lifting Weight for Each Point lb (kg) Mounting Loads for Each Point lb. (kg)ALSModel L1 & L2 L3 & L4 L5 & L6 L7 & L8 R1 & R2 R3 & R4 R5 & R6 R7 & R8 R9 & R10



Copper FinAdd

325 2625 (1189) 1895 (858) 2805 (1271) 1835 (831) 2060 (933) 1955 (886) 1485 (673) 2245 (1017) 1895 (858) 19280 (8734) 18320 (8299) 2750 (1246)

335 2625 (1189) 1895 (858) 2805 (1271) 1840 (833) 2065 (935)) 1955 (886) 1485 (673) 2245 (1017) 1895 (858) 19290 (8738) 18330 (8303) 2750 (1246)

350 2625 (1189) 1895 (858) 2805 (1271) 1840 (833) 2065 (935) 1955 (886) 1485 (673) 2245 (1017) 1895 (858) 19290 (8738) 18330 (8303) 2750 (1246)

365 2625 (1189) 1900 (861) 2805 (1271) 1840 (833) 2070 (938) 1955 (886) 1485 (673) 2245 (1017) 1895 (858) 19300 (8743) 18340 (8308) 2750 (1246)

375 2635 (1194) 1905 (863) 2815 (12750 1845 (836) 2075 (940) 1960 (888) 1490 (675) 2255 (1021) 1900 (861) 19360 (8770) 18400 (8335) 2750 (1246)

385 2640 (1196) 1905 (863) 2815 (12750 1845 (836) 2075 (940) 1965 (890) 1490 (675) 2255 (1021) 1900 (861) 19370 (8775) 18410 (8340) 2750 (1246)

400 2640 (1196) 1905 (863) 2815 (12750 1845 (836) 2075 (940) 1965 (890) 1490 (675) 2255 (1021) 1900 (861) 19370 (8775) 18410 (8340) 2750 (1246)

420 2640 (1196) 1905 (863) 2815 (12750 1845 (836) 2075 (940) 1965 (890) 1495 (677) 2260 (1024) 1920 (870) 19430 (8802) 18510 (8385) 2750 (1246)


83.4(2118)


83.4(2118)

12 IOMM ALS-3

Water PipingDue to the variety of piping practices, it is advisable to follow the recommendations of localauthorities. They can supply the installer with the proper building and safety codes required for asafe and proper installation.

Basically, the piping should be designed with a minimum number of bends and changes in elevation tokeep system cost down and performance up. It should contain:

1. Vibration eliminators to reduce vibration and noise transmission to the building.

2. Shutoff valves to isolate the unit from the piping system during unit servicing.

3. Manual or automatic air vent valves at the high points of the system. Drains at the low parts inthe system. The evaporator should not be the highest point in the piping system.

4. Some means of maintaining adequate system water pressure (e.g., expansion tank or regulatingvalve).

5. Water temperature and pressure indicators located at the unit to aid in unit servicing.

6. A strainer or some means of removing foreign matter from the water before it enters the pump.The strainer should be placed far enough upstream to prevent cavitation at the pump inlet(consult pump manufacturer for recommendations). The use of a strainer will prolong pump lifeand help maintain high system performance levels.

WARNING

7. A strainer must also be placed in the supply water line just prior to the inlet of the evaporator.This will aid in preventing foreign material from entering the evaporator and causing damage ordecreasing its performance. Care must also be exercised if welding pipe to the evaporatorconnections to prevent any weld slag from entering the vessel.

8. The shell-and-tube evaporator has a thermostat and heating cable to prevent freeze-up down to -20°F (-28.8°C). It is suggested that the heating cable be wired to a separate 110V supply circuit.As shipped from the factory, it is factory wired to the control circuit. Any water piping to the unitmust also be protected to prevent freezing.

9. If the unit is used as a replacement chiller on a previously existing piping system, the systemshould be thoroughly flushed prior to unit installation and then regular chilled water analysis andchemical water treatment is recommended immediately at equipment start-up.

10. The total water quantity in the system should be sufficient to prevent frequent "on-off" cycling.For air-conditioning systems, system gallons equal to 7 time the flow rate is recommended.

11. In the event glycol is added to the water system, as an afterthought for freeze protection,recognize that the refrigerant suction pressure will be lower, cooling performance less, and waterside pressure drop greater. If the percentage of glycol is large, or if propylene is employed in lieuof ethylene glycol, the added pressure drop and loss of performance could be substantial.

12. For operations requiring the ice mode feature, logic in MicroTech will adjust the freezestat to apressure equivalent to 13.5°F (7.5°C) below the leaving evaporator water temperature. However, ifa different freezestat pressure value is desired, the freezestat can be manually changed throughMicroTech. Refer to the current OM ALSMICRO for additional information.

CAUTION

If a separate disconnect is used for the 110V supply to the cooler heating cable, it should be clearlymarked so that it is not accidentally shut off during cold seasons.

Prior to insulating the piping and filling the system, a preliminary leak check should be made.

Piping insulation should include a vapor barrier to prevent moisture condensation and possibledamage to the building structure. It is important to have the vapor barrier on the outside of theinsulation to prevent condensation within the insulation on the cold surface of the pipe.

IOMM ALS-3 13

System Water VolumeIt is important to have adequate water volume in the system to provide an opportunity for the chillerto sense a load change, adjust to the change and stabilize. As the expected load change becomesmore rapid, a greater water volume is needed. The system water volume is the total amount of water inthe evaporator, air handling products and associated piping. If the water volume is too low,operational problems can occur including rapid compressor cycling, rapid loading & unloading ofcompressors, erratic refrigerant flow in the chiller, improper motor cooling, shortened equipment lifeand other undesirable occurrences.

For normal comfort cooling applications where the cooling load changes relatively slowly, werecommend a minimum system volume of seven minutes times the flow rate (gpm). For example, if thedesign chiller flow rate is 400 gpm, we recommend a minimum system volume of 2800 gallons (400 gpmX 7 minutes).

For process applications where the cooling load can change rapidly, additional system water volume isneeded. A process example would be the cooling of hot metal objects. The load would be very stableuntil the hot metal is dipped into the water tank. Then, the load would increase drastically. For thistype of application, we recommend that the normal comfort cooling recommendation addressed aboveplus three minutes of ballast for every 10% quick change in load. For example, if the hot metal exampleload changes from a stable 50% load to an immediate 100% load for metal cooling, the recommendedsystem volume would increase to 8800 gallons.

System volume = {400 gpm X 7 minutes} + {(5 increments of 10% increase) X (3 minutes) X 400 gpm}= 8800 gallons

Since there are many other factors that can influence performance, systems may successfully operatebelow these suggestions. However, as the water volume decreases below these suggestions, thepossibility of problems increases.

Variable Water FlowVariable water flow involves changing the water flow through the evaporator as the load changes.McQuay chillers are designed for this duty provided that the rate of change in water flow is slow andthe minimum and maximum flow rates for the vessel are not exceeded.

The recommended change in water flow is listed in the table below. As the number of stages ofcontrol increase, the slower the permissible rate of change in flow rate becomes. The ALS controllogic has timers that limit the rate of unloading or loading allowed. Slow changes allow the chiller theopportunity to sense a change, react to the change and stabilize preventing operational problems.

ALS Size Number ofCompressors

UnloadingSteps

Maximum allowable % perminute of flow change

141 to 218 2 8 10.0

245 to 295 3 12 7.5

325 to 420 4 16 5.0

For example, assume that an ALS with two compressors has a design flow of 500 gpm and theminimum vessel flow rate of 300 gpm. The allowable amount of flow change is 200 gpm. An ALS withtwo compressors has an allowable change rate of 10% of change per minute. Therefore, the maximumrate of change recommended would be 20 gpm/minute (200 X .10).

The water flow through the vessel must remain between the minimum and maximum values listed onFigure 19. If flow drops below the minimum allowable, large reductions in heat transfer can occur. Ifthe flow exceeds the maximum rate, excessive pressure drop and tube erosion can occur.

14 IOMM ALS-3

Evaporator Freeze ProtectionAll evaporators come equipped with thermostatically controlled resistive element heater. When poweris applied to terminals 13 and 16, the heat tape will provide freeze protection down to -20°F (-28.8°C).However, this should not be the only method of freeze protection. Unless the evaporator is flushedand drained as is described below in note 4, two or more of the remaining three recommendations mustbe followed as part of the system design:

1. Continuous circulation of water through the piping and the heat exchanger.

2. The inclusion of glycol solution in the chilled water circuit.

3. The addition of insulation and heat to the exposed piping.

4. Draining and flushing the chiller vessel with glycol during subfreezing weather.

It is the responsibility of the installing contractor and/or on-site maintenance personnel to insure thatthis additional protection is provided. Routine checks should be made to insure adequate freezeprotection is maintained.

Failure to do so may result in damage to unit components. Freeze damage is not considered awarranty failure.

Figure 11, Typical Field Water Piping

Flow SwitchA water flow switch must be mounted in the leaving water line to insure that there will be adequatewater flow to the evaporator before the unit can start. This will safeguard against slugging thecompressors on start-up. It also serves to shut down the unit in the event that water flow isinterrupted to guard against evaporator freeze-up.

A flow switch is available from McQuay under ordering number 017503300. It is a "paddle" typeswitch and adaptable to any pipe size from 1" (25mm) to 8" (203mm) nominal.

Certain minimum flow rates are required to close the switch and are listed in Table 2. Installationshould be as shown in Figure 12.

Electrical connections in the unit control center should be made at terminals 62 and 63. The normallyopen contacts of the flow switch should be wired between these two terminals. Flow switch contactquality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate conduitfrom any high voltage conductors (115 VAC and higher).

Protect all field piping

against freezing

VibrationEliminator

VibrationEliminator

FlowSwitch

Balancingvalve

Gate valveValved

pressuregauge

Waterstrainer

Gate valve

Vent

Outlet

Drain

IOMM ALS-3 15

Figure 12, Flow Switch

Water ConnectionsWater piping to the cooler can be brought up through the bottom of the unit or through the sidebetween the vertical supports. The dimensional drawings in Figure 20 through Figure 22 give thenecessary dimensions and locations for all piping connections. Evaporator piping connections facetoward the left side of the unit when looking at the control panel.

Refrigerant ChargeAll units are designed for use with HCFC-22 (and are compatible with some HCFC alternatives) and areshipped with a full operating charge. The operating charge for each unit is shown in the Physical DataTables. Units ordered with a remote evaporator are shipped with a unit operating charge of refrigerantpumped down in the unit condensers. The McQuay authorized startup technician will top off thesystem charge at startup.

Glycol SolutionsWhen using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and pressuredrop through the cooler may be calculated using the following formulas and tables.

Note: The procedure below does not specify the type of glycol. Use the derate factors found in Table3 for corrections when using propylene glycol and those in Table 4 for ethylene glycol.

1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced value,multiply the chiller’s water system tonnage by the capacity correction factor to find the chiller’scapacity when using glycol.

2. Flow - To determine flow (or delta-T) knowing delta-T (or flow) and capacity:

( )( )( )TDelta

factorflowtonsGPM

−=

24

3. Pressure drop - To determine pressure drop through the cooler, when using glycol, enter thewater pressure drop curve at the water flow rate. Multiply the water pressure drop found there bythe PD factor to obtain corrected glycol pressure drop.

4. To determine glycol system kW, multiply the water system kW by factor called Power.

Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in servicestations) to determine the freezing point. Obtain percent glycol from the freezing point table below.On glycol applications the supplier normally recommends that a minimum of 25% solution by weightbe used for protection against corrosion.

Table 2, Switch Minimum Flow RatesNOMINAL PIPE SIZE

INCHES (MM)MINIMUM REQUIRED FLOW TOACTIVATE SWITCH - GPM (LPS)

5 (127) 58.7 (3.7)6 (152) 79.2 (5.0)8 (203) 140 (8.8)

Note: Water pressure differential switches are notrecommended for outdoor applications.

Flow direction markedon switch

1" (25mm) NPT flowswitch connection

Tee

1 1/4" (32mm) pipedia. min. before switch

1 1/4" (32mm) pipe dia.min. after switch

16 IOMM ALS-3

CAUTION

Do not use automotive grade antifreeze. Industrial grade glycols must be used. Automotive antifreezecontains inhibitors that will cause plating on the copper tubes within the chiller evaporator. The type andhandling of glycol used must be consistent with local codes.

Remote Evaporator

GeneralThe multiple compressor ALS air-cooled chillers are available with the evaporator shipped loose forremote mounting. This allows the main unit to be installed outdoors to save interior room andeliminates the need for anti-freeze solutions and heat tracing of chilled water lines since the chilledwater system is indoors. There are some general guidelines to review before proceeding:

1. R-22 only.

2. Maximum line length of 50 ft (15 m) and Total Equivalent Length (TEL) of 120 ft (37 m).

3. Evaporator not more than 6 ft (1.8 m) above the compressor or 16 ft (5 m) below compressor.

4. No underground piping.

5. No hot gas bypass.

6. Units with remote evaporator are not included in the ARI Certification Program.

The remote evaporator is shipped separately, ready for quick and easy installation at the job site. Allrefrigerant accessories such as liquid-vapor line shut-off valves, replaceable core filter-driers, liquidline solenoid valves, electronic expansion valves, and sightglasses are already included on the ALScondensing unit. The evaporator is equipped with entering and leaving chilled water temperaturesensor wells. The sensors are pre-wired to the ALS unit with 75 feet long sensor leads and must befield connected to the evaporator thermowells. Suction pressure transducers and temperature sensorsmust also be relocated to the evaporator. ALS units are factory charged with a full unit chargepumped down into the condensers. Field piping must be leak tested, evacuated and charged duringinstallation. Do not exceed 150 psig test pressure unless the unit is blanked off from the piping.

Performance Derate FactorsAll performance tables and adjustment factors found in the current version of the Air-Cooled ScrewChiller catalog (PM ALS-x) are applicable for remote evaporator installations. However, a performancederate must be applied to the R-22 performance data due to additional pressure drops in the suctionand liquid lines which cause a loss of compressor performance. These derates are based on a suctionline pressure drop equivalent of approximately 2°F (1°C) change in saturation temperature.

For R-22 applications:

Capacity = Tons (kW) x 0.97 Power = Compressor kW x 0.99

Table 3, Propylene GlycolFREEZEPOINT.%

P.G.oF oC

CAP POWER FLOW PD

10 26 -3 0.987 0.992 1.010 1.06820 19 -7 0.975 0.985 1.028 1.14730 9 -13 0.962 0.978 1.050 1.24840 -5 -21 0.946 0.971 1.078 1.36650 -27 -33 0.965 0.965 1.116 1.481

Table 4, Ethylene GlycolFREEZEPOINT.%

E.G.oF oC

CAP POWER FLOW PD

10 26 -3 0.991 0.996 1.013 1.07020 18 -8 0.982 0.992 1.040 1.12930 7 -14 0.972 0.986 1.074 1.18140 -7 -22 0.961 0.976 1.121 1.26350 -28 -33 0.946 0.966 1.178 1.308

IOMM ALS-3 17

Refrigerant PipingGeneralCareful design of the refrigerant piping is necessary for efficient system operation. The refrigerantpiping should be designed for a low refrigerant pressure drop to obtain maximum capacity andefficiency while maintaining adequate velocity. Lines should slope in the direction of flow to assuregood oil return to the compressors. Cost considerations favor keeping line sizes as small as possiblewhile not exceeding acceptable pressure drops in order to maintain unit performance.

NOTEAll refrigerant piping must be reviewed and approved by McQuay Application

Engineers prior to order entry and will be verified by McQuay startup technicians.

Equivalent Line LengthsRecommended refrigerant line sizes are based on equivalent line lengths of straight pipe, that is, acombination of straight pipe, fittings and valves. The pressure drop through valves and fittings isdetermined by establishing the equivalent straight length of pipe of the same size with the samefriction loss. The "Total Equivalent Length" is the sum of the "Lineal Line Length" and theappropriate "Valve and Fitting Losses in Equivalent Feet of Pipe for Field Supplied Piping" given inTable 5

Table 5, Fitting Equivalent Feet of PipeLine Size (in.) Angle Valve Globe Valve 90° Std. Radius Elbow 90° Long Radius Elbow

1 1/8 12 29 2.6 1.71 3/8 15 38 3.3 2.31 5/8 18 43 4.0 2.62 1/8 24 55 5.0 3.32 5/8 29 69 6.0 4.13 1/8 35 84 7.5 5.0

Location and ArrangementRefrigerant lines should be as short and direct as possible to minimize tubing and fittings. Longradius elbows must be used (except for traps) to minimize the pressure drops. Traps should be asshort as possible to minimize oil accumulation. Refrigerant piping should be arranged so that normalinspection of the equipment is not hindered. Adequate clearance should be provided betweenrefrigerant piping and adjacent walls for insulation. Piping should be run so that it does not interferewith compressor service access, passages or obstruct headroom, windows and doors. Suction linehangers must be sized and located to support the weight of the piping in accordance with good pipingpractice.

Horizontal portions of the suction lines must be downward sloping toward the compressors. Slope allpiping in the direction of flow. Vertical portions of the suction lines must be sized for oil return atminimum compressor load.

Note: Double section risers must not be utilized on any circuit. Traps must be provided as shown onFigure 13 and Figure 14.

Suction Line SizingPressure drop in the suction line reduces system capacity and efficiency because it forces thecompressor to operate at lower suction pressure. The suction line should be sized for a pressure dropapproximately equivalent of 2°F (1°C) change in saturation temperature. For suction line sizing seeTable 7 and table 8. For applications with the evaporator below the ALS unit, the vertical section ofthe suction lines must be sized to return oil to the compressors at the minimum compressor capacitystep.

18 IOMM ALS-3

Example of Suction Line Size Calculation

ALS150C condensing unit with refrigerant R-22

Evaporator located 5 feet below the ALS compressor

Lineal length of horizontal suction line is 25 feet

Suction line requires 7 long radius (90°) elbows; 3 in the horizontal, 4 in the riser

From Table 6, the nominal circuit capacities for circuit 1 and 2 are 65 and 80 tons respectively

Total lineal suction line length = 30 feet each circuit (25 feet horizontal plus 5 feet vertical riser).For the first try, assume that the total equivalent suction line length is twice the lineal suctionline length.

Therefore the estimated total equivalent suction line length = 60 feet

From Table 7 and Table 8, For nominal circuit capacities of 65 & 80 tons and total equivalent linelength of 60 ft, the suction line size = 2 5/8" for horizontal lines and 2 1/8" for vertical lines.

From Table 5, Fitting loss for 2 5/8" long radius (90°) elbow = 4.1 ft, and 3.3 ft for the 2 1/8 elbows.

Therefore fitting loss in equivalent feet of pipe for (3) 2 5/8" long radius (90°) elbow = 12.3 ft, and13.2 ft for (4) 2 1/8" elbows.

Therefore the actual equivalent suction line length = 30 + 12.3 + 13.2 = 55.5 feet

From and Table 8, For nominal circuit capacities of 65 & 80 tons and equivalent line length of 55.5 ftthe suction line size is correct.

Table 6, ALS 141C-420C Nominal Circuit CapacitiesCircuit 1 Circuit 2 Circuit 3 Circuit 4

ALS ModelTons (kW) Tons (kW) Tons (kW) Tons (kW)

141 65 (229) 65 (229) - -150 65 (229) 80 (262) - -171 80 (262) 80 (262) - -186 80 (262) 95 (334) - -190 80 (262) 95 (334) - -200 95 (334) 95 (334) - -206 95 (334) 95 (334) - -218 95 (334) 95 (334) - -245 65 (229) 80 (262) 80 (262) -260 80 (262) 80 (262) 80 (262) -270 80 (262) 80 (262) 95 (334) -275 80 (262) 95 (334) 95 (334) -295 95 (334) 95 (334) 95 (334) -325 65 (229) 65 (229) 80 (262) 80 (262)335 65 (229) 80 (262) 80 (262) 80 (262)350 80 (262) 80 (262) 80 (262) 80 (262)365 80 (262) 80 (262) 80 (262) 95 (334)375 80 (262) 80 (262) 95 (334) 95 (334)385 80 (262) 95 (334) 95 (334) 95 (334)400 95 (334) 95 (334) 95 (334) 95 (334)420 95 (334) 95 (334) 95 (334) 95 (334)

Table 7, Vertical Upflow Suction Line Sizes

Vertical Upflow Suction LinesNominal CircuitCapacity

Tons (kW) Equivalent Line Length Ft (m) Suction Line Size (in.)

40 (12) 2 1/865 (229)

75 (23) 2 1/840 (12) 2 1/8

80 (262)75 (23) 2 1/840 (12) 2 5/8

95 (334)75 (23) 2 5/8

IOMM ALS-3 19

Table 8, Horizontal and Vertical Downflow Suction Line SizesVertical Downflow and Horizontal Suction LinesNominal Circuit

CapacityTons (kW)

Equivalent Line Length Ft (m) Suction Line Size, in.

40 (12) 2 5/865 (229) 75 (23) 2 5/8

115 (35) 2 5/840 (12) 2 5/8

80 (262) 75 (23) 2 5/8115 (35) 3 1/840 (12) 2 5/8

95 (334) 75 (23) 3 1/8115 (35) 3 1/8

Liquid-Vapor LinesThe liquid-vapor line from the ALS condensing unit to the evaporator liquid connection is not aconventional liquid line since it carries both liquid and vapor. The compressors on the ALS unitsutilize a liquid cooled motor and an economizer. Therefore the expansion valve which feeds the fullflow of liquid refrigerant into the compressor for motor cooling is mounted in the liquid line betweenthe condenser sub-cooling coil and the compressor inlet, not at the evaporator inlet. The liquid-vaporline to the evaporator is a low pressure line downstream of the expansion valve and the size is slightlylarger than a normal liquid line. For liquid line sizing see Table 9 and Table 10.

Table 9, Vertical Upflow Liquid-Vapor Line SizesVertical Upflow Liquid-Vapor LinesNominal Circuit

CapacityTons (kW)

Equivalent Line LengthFt (m)

Liquid-Vapor Line Sizeo.d (in.)

40 (12) 1 3/865 (229) 75 (23) 1 3/8

40 (12) 1 3/880 (262) 75 (23) 1 3/8

40 (12) 1 5/895 (334) 75 (23) 1 5/8

Table 10, Horizontal and Vertical Downflow Liquid-Vapor Line SizesVertical Downflow and Horizontal Liquid-Vapor LinesNominal Circuit

CapacityTons (kW)

Equivalent Line LengthFt (m)

Liquid-Vapor Line Size o.d (in.)

40 (12) 1 3/865 (229) 75 (23) 1 3/8

115 (35) 1 3/840 (12) 1 3/8

80 (262) 75 (23) 1 5/8115 (35) 1 5/840 (12) 1 5/8

95 (334) 75 (23) 1 5/8115 (35) 1 5/8

Figure 13, Evaporator Above ALS Unit

ALS Unit

Trap

Suction Line

Evaporator

20 IOMM ALS-3

Figure 14, Evaporator Below ALS Unit

ALS Unit

Trap

Suction Line

Evaporator

NOTE: Keep the trap width at a minimum to avoid trapping excessive oil.

InsulationAll piping joints and fittings must be thoroughly leak tested before insulation is applied. Suction linesmust be insulated and should not be installed underground. Suction line insulation must be selectedto prevent condensation under local ambient conditions with the lines at 40°F to 50°F (4.4°C to 10°C)operating temperatures. The liquid-vapor lines will operate at 40°F to 60°F (4.4°C to 15.6°C) and mustalso be insulated to prevent sweating and heat gain.

IOMM ALS-3 21

Startup ProceduresNOTE: McQuayService or a factory authorized McQuay service agent must do initial start-up andcommissioning.

Filter DriersFollowing an initial 24 hour operation the pressure drop across the replaceable core filter-drier shouldbe checked. If this pressure drop exceeds the values given in Table 11 at the various load conditionsthe filter drier cores must be replaced. Also if the moisture indicating sight glass shows a wet systemcondition after 24 hours of operation the filter cores must be changed. This should remove anycontaminants introduced during field piping. The filter drier cores must also be changed anytime thesystem is opened for servicing.

Table 11, Filter Drier Pressure DropPercent Circuit

Loading (%)Maximum Recommended Pressure Drop Across Filter Drier

psig (kPa)

100 7 (48.3)

75 5 (34.5)

50 3 (20.7)

25 3 (20.7)

Refrigerant and Oil ChargeThe relative position of the ALS unit and the evaporator and the distance between them plays acritical role in determining suction and liquid line sizes and the field refrigerant and oil charges. ALSunits with the remote evaporator option are shipped with a unit operating charge of refrigerant and oil.It will be necessary to evacuate the evaporator and field installed line and top off the charge SeeTable 12 for refrigerant charge for suction and liquid-vapor lines. McQuay Service will supply andadd additional oil as required. The correct oil is Planetelf ACD68AW, McQuay Part No. 735030439 (5gal.), 735030438 (1 gal.).

Charging ProcedureThe calculated refrigerant charge must be added through the factory supplied charging valve locatedon the liquid-vapor line coming out of the compressor. Sufficient charge must be added to clear theliquid line sight glass located at the outlet of the condenser. Add an extra 10 lb. of refrigerant after thesight glass is clear.

Table 12, Refrigerant Charge for Suction and Liquid-Vapor LinesSuction Line Refrigerant Charge

lb (kg)Liquid-Vapor Line Refrigerant Charge

lb (kg)Lineal Tubing

Lengthft (m) Line (in.) R-22 Line (in.) R-22

2 1/8 0.33 (0.15) 1 3/8 3.6 (1.6)10 (3) 2 5/8 0.51 (0.23) 1 5/8 5.0 (2.3)

3 1/8 0.71 (0.32)2 1/8 0.66 (0.30) 1 3/8 7.2 (3.3)

20 (6) 2 5/8 1.02 (0.46) 1 5/8 10.0 (4.5)3 1/8 1.42 (0.64)2 1/8 0.99 (0.45) 1 3/8 10.8 (4.9)

30 (9) 2 5/8 1.53 (0.69) 1 5/8 15.0 (6.8)3 1/8 2.13 (0.96)2 1/8 1.32 (0.60) 1 3/8 14.4 (6.5)

40 (12) 2 5/8 2.04 (0.92) 1 5/8 20.0 (9.0)3 1/8 2.84 (1.29)

Notes:

1. The only approved oil is that identified on the label attached to the compressors. All POE oils arehygroscopic and care should be exercised in handling the oil to avoid absorption and retention ofmoisture.

2. Do not leave the oil container open for more than a minute while charging oil. Do not use oil thathas not been properly sealed and stored.

3. Charge must never be added through the compressor suction line

22 IOMM ALS-3

DimensionsUse the ALS dimension drawings Figure 20 through Figure 22 for the ALS with remote evaporator.The refrigerant connections are located approximately where the refrigerant connections to the unitmounted evaporator are on a packaged chiller. The remote evaporator dimensions are Figure 15through Figure 18.

Dimensions, Remote EvaporatorFigure 15, Evaporator for ALS 141 - ALS 200

Unit Weights lb. (kg) R-22 Operating Charge lb. (kg)ALS

Model

Evaporator

Model

WaterVolume

gal. (l)

RefrigerantVolume

cu. ft. (L)Operating Shipping Circuit 1 Circuit 2

141 CDE350332801 34 (128) 1.4 (40.0) 934 (424) 635 (288) 34 (15.4) 34 (15.4)150-200 CDE350332901 40 (150) 1.8 (52.4) 1127 (512) 758 (343) 45 (20.4) 45 (20.4)

Overall Dimensions in. (mm)ALS

Model Length "K" Height "A" "B" "C" "D" "H" "J"

Conn.

"G"

141 94.6 (2403) 17.8 (452) 11.0 (279) 10.2 (259) 12.8 (325) 6.4 (163) 85.2 (2164) 5 (152)150-200 95.5 (2426) 18.4 (467) 12.0 (305) 10.2 (259) 14.0 (356) 6.8 (173) 84.0 (2134) 8 (203)

IOMM ALS-3 23

Figure 16, Evaporator for ALS 206 - ALS 218

Weights lb. (kg)R-22 Opn Charge lb.

(kg)ALS

Model

Evaporator

Model

Water Volume

gal. (l)

Refrig Volume

cu. ft. (l)Operating Shipping Circuit 1 Circuit 2

206 CDE350281651 55 (208) 2.4 (67.9) 1464 (665) 943 (428) 57 (25.8) 57 (25.8)218 CDE350282101 98 (373) 2.8 (79.2) 2028 (921) 1121 (509) 68 (30.9) 68 (30.9)

Dimensional DataALS

Model A C D H J K

206 21.3 (542) 12.1 (307) 16.0 (406) 6.9 (176) 84.5 (2149) 96.7 (2459)218 23.6 (601) 12.4 (315) 20.0 (508) 9.2 (235) 86.6 (2202) 99.7 (2533)

24 IOMM ALS-3


Weights lb. (kg)R-22 Operating Charge lb.

(kg)ALS

Model

Evaporator

Model

Water

Volume

gal. (l)

Refrig

Volume

cu. ft. (l) Operating ShippingCircuit

1

Circuit

2Circuit 3

245-260 CDE350282111 98 (371) 2.91 (82.3) 2035 (924) 1130 (513) 47 (21) 47 (21) 47 (21)270-295 CDE350282121 94 (357) 3.3 (93.4) 2068 (939) 1174 (533) 53 (24) 53 (24) 53 (24)

IOMM ALS-3 25


Weights lb. (kg) R-22 Operating Charge lb. (kg)ALS

Model

Evaporator

Model

Water Vol.

gal. (l)

Refrig Vol.

cu. ft. (l) Operating Shipping Circuit 1 Circuit 2 Circuit 3 Circuit 4

325-400 CDE350283101 115 (435) 4.1 (116) 2529 (1148) 1423 (646) 49 (22) 49 (22) 49 (22) 49 (22)420 CDE350283111 110 (416) 4.7 (133( 2575 (1169) 1484 (674) 56 (25) 56 (25) 56 (25) 56 (25)

Water Flow and Pressure Drop

The chilled water flow through the evaporator should be adjusted to meet specified conditions. Theflow rates must fall between the minimum and maximum values shown in. Flow rates below theminimum values shown will result in laminar flow that will reduce efficiency, cause erratic operation ofthe electronic expansion valve and could cause low temperature cutouts. On the other hand flow ratesexceeding the maximum values shown can cause erosion on the evaporator water connections andtubes.

Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It isimportant not to include valve or strainer pressure drop in these readings.

26 IOMM ALS-3

Figure 19, Evaporator Pressure Drops

ALS 141

ALS 206

ALS 150-200

ALS 218-260

ALS 270-295 ALS 325-400

ALS 420

Table 13, Minimum/Maximum Flow RatesALSUnitSize

MinimumFlowgpm

PressureDrop ft.

MaximumFlow gpm

PressureDrop ft.

ALSUnitSize

MinimumFlow gpm

PressureDrop ft.

MaximumFlow gpm

PressureDrop ft.

141 187 4.0 498 24.2 275 395 4.2 1052 37.8150 210 4.2 559 28.5 295 413 4.6 1100 41.9171 234 5.2 623 35.3 325 445 3.9 1186 34.8186 255 6.1 680 41.9 335 463 4.2 1235 38.1190 260 6.4 692 43.4 350 484 4.7 1291 42.1200 276 7.2 737 49.0 365 498 5.0 1328 44.8206 285 7.5 761 50.4 375 531 5.8 1417 51.9218 307 5.0 818 36.8 385 546 6.0 1457 55.2245 339 5.9 903 43.6 400 565 6.6 1506 59.4260 360 6.7 960 49.4 420 609 8.8 1623 76.2270 380 3.8 1012 34.7

IOMM ALS-3 27

Physical DataTable 14, Physical Data, ALS 141C – ALS 186C

ALS MODEL NUMBERDATA 141C 150C 171C 186C

Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2BASIC DATA

Unit Cap. @ ARI Conditions, tons(kW)

124.5 (436) 139.7 (489) 155.8 (545) 170 (595)

Unit Operating Charge R-22, lbs (kg) 140 (63.5) 140 (63.5) 140 (63.5) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 160 (72.6)Cabinet DimensionsL x W x H, in. (mm)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

Unit Operating Weight, lbs. (kg) 9700 (4395) 9880 (4475) 9890 (4480) 9900 (4485)Unit Shipping Weight, lbs (kg) 9420 (4270) 9550 (4325) 9560 (4330) 9570 (4335)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 65 (230) 65 (230) 65 (230) 80 (280) 80 (280) 80 (280) 80 (280) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft2. (m2) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7)

Finned Height x Finned Length ft. (mm)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 10 - 28 (711) 10 - 28 (711) 12 - 28 (711) 12 - 28 (711)

No. of Motors -- hp (kW) 10 - 1.5 (1.1) 10 - 1.5 (1.1) 12 - 1.5 (1.1) 12 - 1.5 (1.1)Fan & Motor RPM, 60Hz 1140 1140 1140 1140

60 Hz Fan Tip Speed, fpm 8357 8357 8357 835760 Hz Total Unit Airflow, ft3/min 90200 90200 108240 108240

EVAPORATOR, DIRECT EXPANSIONShell Dia.- Length

in.(mm) - in. (mm)12.75 – 94.6(324 - 2403)

14.0 – 95.5(356 - 2425)

14.0 – 95.5(356 - 2425)

14.0 – 95.5(356 - 2425)

Evaporator R-22 Charge lbs (kg) 34 (15.4) 34 (15.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4)Water Volume, gallons (liters) 34 (129) 40 (151) 40 (151) 40 (151)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)

Table 15, Physical Data, ALS 190C – ALS 218CALS MODEL NUMBER

DATA 190C 200C 206C 218CCkt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2

BASIC DATAUnit Cap. @ ARI Conditions, tons

(kW)173.1 (606) 184.2 (645) 190.3 (666) 204.4 (715)

Unit Operating Charge R-22, lbs (kg) 170 (77.0) 180 (81.5) 180 (81.5) 180 (81.5) 185 (83.8) 185 (83.8) 210 (95.1) 210 (95.1)Cabinet Dimensions,L x W x H, in. (mm)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

Unit Operating Weight, lbs. (kg) 10620 (4810) 10630 (4815) 10960 (4965) 11550 (5230)Unit Shipping Weight, lbs (kg) 10290 (4660) 10300 (4665) 10500 (4755) 10730 (4860)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 80 (280) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft2. (m2) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5)

Finned Height x Finned Lengthft. (mm)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711)

No. of Motors -- hp (kW) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 2.0 (1.5)Fan & Motor RPM, 60Hz 1140 1140 1140 1140

60 Hz Fan Tip Speed, fpm 8357 8357 8357 835760 Hz Total Unit Airflow, ft3/mon 126280 126280 126280 138908

EVAPORATOR, DIRECT EXPANSIONShell Dia. -- Lengthin.(mm) - in. (mm)

14.0 – 95.5(356 - 2425)

14.0 – 95.5(356 - 2425)

16.0 – 96.8(406 - 2459)

20.0 – 99.7(508 - 2532)

Evaporator R-22 Charge lbs (kg) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 57 (25.8) 57 (25.8) 68 (30.8) 68 (30.8)Water Volume, gallons (liters) 40 (151) 40 (151) 55 (208) 98 (371)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)

28 IOMM ALS-3


DATA 245C 260C 270CCKT. 1 CKT. 2 CKT. 3 CKT. 1 CKT. 2 CKT. 3 CKT. 1 CKT. 2 CKT. 3


(kW)225.7 (790) 239.8 (839) 253.0 (886)

Unit Operating Charge R-22, lbs (kg) 140 (63.5) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 160 (72.6)Cabinet Dimensions, L x W x H, in.

(mm)355 x 83.4 x 94.5

(9017 x 2118 x 2400)355 x 83.4 x 94.5

(9017 x 2118 x 2400)355 x 83.4 x 94.5

(9017 x 2118 x 2400)Unit Operating Weight, lbs. (kg) 14840 (6725) 14850 (6730) 14880 (6740)Unit Shipping Weight, lbs (kg) 14030 (6355) 14040 (6360) 14090 (6385)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 65 (230) 80 (280) 80 (280) 80 (280) 80 (280) 80 (280) 80 (280) 80 (280) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft2. (m2) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7)


80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

160 x 104(4064 x 2642)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

160 x 104(4064 x 2642)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

160 x 104(4064 x 2642)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 16 - 28 (711) 18 - 28 (711) 18 - 28 (711)

No. of Motors -- hp (kW) 16 - 1.5 (1.1) 18 - 1.5 (1.1) 18 - 1.5 (1.1)Fan & Motor RPM, 60Hz 1140 1140 1140

60 Hz Fan Tip Speed, fpm 8357 8357 835760 Hz Total Unit Airflow, ft3/min 144320 162360 162360


20.0 – 99.7(508 - 2532)

20.0 – 99.7(508 - 2532)

20.0 – 99.7(508 - 2532)

Evaporator R-22 Charge lbs (kg) 47 (21.3) 47 (21.3) 47 (21.3) 47 (21.3) 47 (21.3) 47 (21.3) 52 (23.6) 52 (23.6) 52 (23.6)Water Volume, gallons (liters) 98 (371) 98 (371) 94 (356)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068)


DATA 275C 295CCKT. 1 CKT. 2 CKT. 3 CKT. 1 CKT. 2 CKT. 3


(kW)263.1 (921) 275.3 (964)

Unit Operating Charge R-22, lbs (kg) 150 (68.1) 160 (72.6) 160 (72.6) 160 (72.6) 160 (72.6) 160 (72.6)Cabinet Dimensions, L x W x H, in.

(mm)355 x 83.4 x 94.5

(9017 x 2118 x 2400)355 x 83.4 x 94.5

(9017 x 2118 x 2400)Unit Operating Weight, lbs. (kg) 14890 (6745) 14900 (6750)Unit Shipping Weight, lbs (kg) 14100 (6390) 14110 (6390)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 80 (280) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft2. (m2) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7)


80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

160 x 104(4064 x 2642)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

160 x 104(4064 x 2642)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 18 - 28 (711) 18 - 28 (711)

No. of Motors -- hp (kW) 18 - 1.5 (1.1) 18 - 1.5 (1.1)Fan & Motor RPM, 60Hz 1140 1140

60 Hz Fan Tip Speed, fpm 8357 835760 Hz Total Unit Airflow, ft3/min 162360 162360


20.0 – 99.7(508 - 2532)

20.0 – 99.7(508 - 2532)

Evaporator R-22 Charge lbs (kg) 52 (23.6) 52 (23.6) 52 (23.6) 52 (23.6) 52 (23.6) 52 (23.6)Water Volume, gallons (liters) 94 (356) 94 (356)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068)

IOMM ALS-3 29

Table 18, Physical Date, ALS 325C – ALS 365CALS MODEL NUMBER

DATA 325C 335C 350C 365CCkt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4

BASIC DATAUnit Capacity @ ARIConditions, tons (kW)

296.5 (1038) 308.7 (1080) 322.8 (1130) 331.9 (1162)

Unit Operating ChargeR-22, lbs (kg)

155(70.3)

155(70.3)

160(72.6)

160(72.6)

155(70.3)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

160(72.6)

170(77.1)

Cabinet Dimensions,L x W x H, in. (mm)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

Operating Wt., lbs(kg)

19280 (8735) 19290 (8740) 19290 (8740) 19300 (8740)

Shipping Wt., lbs (kg) 18320 (8300) 18330 (8305) 18330 (8305) 18340 (8310)COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity,tons (kW)

65(230)

65(230)

80(280)

80(280)

65(230)

80(280)

80(280)

80(280)

80(280)

80(280)

80(280)

80(280)

80(280)

80(280)

80(280)

95(335))

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft2.

(m2)96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

96.3(8.9)

Finned Height xFinned Length ft.

(mm)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

80x173(2032x4394)

Fins Per Inch x Rows 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

Fan Qty., Dia. in.(mm)

20 – 28 (711) 20 - 28 (711) 20 – 28 (711) 20 - 28 (711)

No. of Motors, hp(kW)

20 - 2.0 (1.5) 20 - 2.0 (1.5) 20 - 2.0 (1.5) 20 - 2.0 (1.5)

Fan & Motor RPM 1140 1140 1140 1140Fan Tip Speed, fpm 8357 8357 8357 8357Unit Airflow, ft3/min 198440 198440 198440 198440

EVAPORATOR, DIRECT EXPANSIONShell Dia. Lengthin.(mm) - in. (mm)

22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

Evaporator R-22Charge lbs (kg)

49(22.2)

49(22.2)

49 (22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)49

(22.2)Water Volume, gallons

(liters)115 (435) 115 (435) 115 (435) 115 (435)

Max. Water Pressure,psi (kPa)

152 (1048) 152 (1048) 152 (1048) 152 (1048)

Max. RefrigerantPressure, psi (kPa)

300 (2068) 300 (2068) 300 (2068) 300 (2068)

30 IOMM ALS-3


DATA 375C 385C 400C 420CCkt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4 Ckt 1 Ckt 2 Ckt 3 Ckt 4

BASIC DATAUnit Capacity @ ARIConditions, tons (kW)

354.2 (1240) 364.3 (1275) 376.5 (1318) 405.8 (1420)

Unit Operating ChargeR-22, lbs (kg)

175(79.4)

175(79.4)

180(81.6)

180(81.6)

175(79.4)

180(81.6)

180(81.6)

180(81.6)

180(81.6)

180(81.6)

180(81.6)

180(81.6)

190(86.2)

190(86.2)

190(86.2)

190(86.2)

Cabinet Dimensions,L x W x H, in. (mm)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

458.5 x 83.4 x 94.5(11646 x 2118 x 2400)

Unit OperatingWeight, lbs (kg)

19360(8770)

19370(8775)

19370(8775)

19430(8800)

Unit Shipping Weight,lbs (kg)

18400(8335)

18410(8340)

18410(8340)

18510(8385)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity,

tons (kW)80

(280)80

(280)95

(335)95

(335)80

(280)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)95

(335)CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER

Coil Face Area, ft.(m2)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

115.6(10.7)

Finned Height xFinned Length, ft.

(mm)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

80x208(2032x5283)

Fins Per Inch x RowsDeep

16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPEFan Qty. Dia., in.

(mm)24 – 28 (711) 24 – 28 (711) 24 – 28 (711) 24 – 28 (711)

No. of Motors, hp(kW)

24 - 2.0 (1.5) 24 - 2.0 (1.5) 24 - 2.0 (1.5) 24 - 2.0 (1.5)

Fan RPM, 60Hz 1140 1140 1140 1140Fan Tip Speed, fpm 8357 8357 8357 8357Unit Airflow, ft3/min 238128 238128 238128 257180


22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

22.0 – 100.7(559 - 2558)

Evaporator R-22Charge lbs (kg)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

49(22.2)

56(25.4)

56(25.4)

56(25.4)

56(25.4)

Water Volume, gallons(liters)

115 (435) 115 (435) 115 (435) 110 (416)

Max. Water Pressure,psi (kPa)

152 (1048) 152 (1048) 152 (1048) 152 (1048)

Max. RefrigerantPressure, psi (kPa)

300 (2068) 300 (2068) 300 (2068) 300 (2068)

IOMM ALS-3 31

Compressor Staging

ALS 141-218

Table 20, Two Compressors Available

STAGE UP LEADCOMPRESSOR

LAG 1COMPRESSOR

UNITCAPACITY

STAGE DOWN LEADCOMPRESSOR

LAG 1COMPRESSOR

UNITCAPACITY

1 - - 0% 1 25% 0% 12.5%2 50% 0% 25.0% 2 50% 0% 25.0%3 75% 0% 37.5% 3 75% 0% 37.5%4 50% 50% 50.0% 4 50% 50% 50.0%5 75% 50% 62.5% 5 75% 50% 62.5%6 75% 75% 75.0% 6 75% 75% 75.0%7 100% 75% 87.5% 7 100% 75% 87.5%8 100% 100% 100.0% 8 100% 100% 100.0%

Table 21, One Compressor Available

STAGE UP LEADCOMPRESSOR

LAG 1COMPRESSOR

UNITCAPACITY

STAGE Down LEADCOMPRESSOR

LAG 1COMPRESSOR

UNITCAPACITY

1 - - 0% 1 25% 0% 12.5%2 50% 0% 25.0% 2 50% 0% 25.0%3 75% 0% 37.5% 3 75% 0% 37.5%4 50% 0% 50.0% 4 100% 0% 50.0%

ALS 245-295

Table 22, Three Compressors AvailableSTAGE

UPLEAD

COMP.LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

STAGEDOWN

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

1 - - - 0% 1 25% 0% 0% 8.3%2 50% 0% 0% 16.7% 2 50% 0% 0% 16.7%3 75% 0% 0% 25.0% 3 75% 0% 0% 25.0%4 50% 50% 0% 33.3% 4 50% 50% 0% 33.3%5 75% 50% 0% 41.7% 5 75% 50% 0% 41.7%6 75% 75% 0% 50.0% 6 50% 50% 50% 50.0%7 75% 50% 50% 58.3% 7 75% 50% 50% 58.3%8 75% 75% 50% 66.7% 8 75% 75% 50% 66.7%9 75% 75% 75% 75.0% 9 75% 75% 75% 75.0%10 100% 75% 75% 83.3% 10 100% 75% 75% 83.3%11 100% 100% 75% 91.6% 11 100% 100% 75% 91.6%12 100% 100% 100% 100.0% 12 100% 100% 100% 100.0%

Table 23, Two compressors availableSTAGE

UPLEAD

COMP.LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

STAGEDOWN

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

1 - - - 0% 1 25% 0% 0% 8.3%2 50% 0% 0% 16.7% 2 50% 0% 0% 16.7%3 75% 0% 0% 25.0% 3 75% 0% 0% 25.0%4 50% 50% 0% 33.3% 4 50% 50% 0% 33.3%5 75% 50% 0% 41.7% 5 75% 50% 0% 41.7%6 75% 75% 0% 50.0% 6 75% 75% 0% 50.0%7 100% 75% 0% 58.3% 7 100% 75% 0% 58.3%8 100% 100% 0% 66.7% 8 100% 100% 0% 66.7%

Table 24, One Compressor AvailableSTAGE

UPLEAD

COMP.LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

STAGEDOWN

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

UNITCAPACITY

1 - - - 0% 1 25% 0% 0% 8.3%2 50% 0% 0% 16.7% 2 50% 0% 0% 16.7%3 75% 0% 0% 25.0% 3 75% 0% 0% 25.0%4 100% 0% 0% 33.3% 4 100% 0% 0% 33.3%

32 IOMM ALS-3

ALS 325-420

Table 25, Four Compressors AvailableSTAGE UP LEAD

COMP.LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

STAGEDOWN

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

1 - - - - 0.0% 1 25% 0% 0% 0% 6.3%2 50% 0% 0% 0% 12.5% 2 50% 0% 0% 0% 12.5%3 75% 0% 0% 0% 18.8% 3 75% 0% 0% 0% 18.8%4 50% 50% 0% 0% 25.0% 4 50% 50% 0% 0% 25.0%5 75% 50% 0% 0% 31.3% 5 75% 50% 0% 0% 31.3%6 75% 75% 0% 0% 37.5% 6 50% 50% 50% 0% 37.5%7 75% 50% 50% 0% 43.8% 7 75% 50% 50% 0% 43.8%8 75% 75% 50% 0% 50.0% 8 50% 50% 50% 50% 50.0%9 75% 75% 75% 0% 56.3% 9 75% 50% 50% 50% 56.3%10 75% 75% 50% 50% 62.5% 10 75% 75% 50% 50% 62.5%11 75% 75% 75% 50% 68.8% 11 75% 75% 75% 50% 68.8%12 75% 75% 75% 75% 75.0% 12 75% 75% 75% 75% 75.0%13 100% 75% 75% 75% 81.3% 13 100% 75% 75% 75% 81.3%14 100% 100% 75% 75% 87.5% 14 100% 100% 75% 75% 87.5%15 100% 100% 100% 75% 93.8% 15 100% 100% 100% 75% 93.8%16 100% 100% 100% 100% 100.0% 16 100% 100% 100% 100% 100.0%

Table 26, Three Compressors Available

STAGE LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

1 - - - - 0.0% 25% 0% 0% 0% 6.3%2 50% 0% 0% 0% 12.5% 50% 0% 0% 0% 12.5%3 75% 0% 0% 0% 18.8% 75% 0% 0% 0% 18.8%4 50% 50% 0% 0% 25.0% 50% 50% 0% 0% 25.0%5 75% 50% 0% 0% 31.3% 75% 50% 0% 0% 31.3%6 75% 75% 0% 0% 37.5% 50% 50% 50% 0% 37.5%7 75% 50% 50% 0% 43.8% 75% 50% 50% 0% 43.8%8 75% 75% 50% 0% 50.0% 75% 75% 50% 0% 50.0%9 75% 75% 75% 0% 56.3% 75% 75% 75% 0% 56.3%10 100% 75% 75% 0% 62.5% 100% 75% 75% 0% 62.5%11 100% 100% 75% 0% 68.8% 100% 100% 75% 0% 68.8%12 100% 100% 100% 0% 75.0% 100% 100% 100% 0% 75.0%

Table 27, Two Compressors Available

STAGE LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

1 - - - - 0.0% 25% 0% 0% 0% 6.3%2 50% 0% 0% 0% 12.5% 50% 0% 0% 0% 12.5%3 75% 0% 0% 0% 18.8% 75% 0% 0% 0% 18.8%4 50% 50% 0% 0% 25.0% 50% 50% 0% 0% 25.0%5 75% 50% 0% 0% 31.3% 75% 50% 0% 0% 31.3%6 75% 75% 0% 0% 37.5% 75% 75% 0% 0% 37.5%7 100% 75% 0% 0% 43.8% 100% 75% 0% 0% 43.8%8 100% 100% 0% 0% 50.0% 100% 100% 0% 0% 50.0%

Table 28, One Compressor Available

STAGE LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

LEADCOMP.

LAG 1COMP.

LAG 2COMP.

LAG 3COMP.

UNITCAPACITY

1 - - - - 0.0% 25% 0% 0% 0% 6.3%2 50% 0% 0% 0% 12.5% 50% 0% 0% 0% 12.5%3 75% 0% 0% 0% 18.8% 75% 0% 0% 0% 18.8%4 100% 0% 0% 0% 25.0% 100% 0% 0% 0% 25.0%

IOMM ALS-3 33

Dimensional Data

Figure 20, Dimensions, ALS 141C – ALS 218CNote: See page 10 for lifting locations, mounting locations, weights and mounting loads.

No

tes:

1. A

ll di

men

sion

s in

inch

es (m

m).

2. O

nly

wat

er c

onne

ctio

ns a

s sh

own

are

avai

labl

e.

Vic

taul

ic C

onne

ctio

nsC

oupl

ings

by

Oth

ers.

Pow

erC

ente

r

Con

trol

Cen

ter

83.4

(211

8)

Con

trol

wiri

ngen

try k

nock

outs

for ½

(13)

cond

uit b

oth

side

s of

uni

t.

92.5

(235

0)

6.0

(152

) 48.6

(123

4)

8.1

(206

)

Pow

er e

ntry

loca

tion

this

sid

e on

ly.

2 ad

ditio

nal k

nock

outs

6.0

(152

)ab

ove

and

belo

w th

is o

peni

ngfo

r mul

tiple

pow

er s

uppl

y.

“A”

Sta

ndar

d C

oil G

uard

s

28.5

(724

)

6.50

(16

5)

“D”

“C”

“B”

Out

let

Inle

tC

ompr

esso

r#1

Com

pres

sor

#2

Air

Dis

char

ge

“E”

“Y”

141C

150C

171C

186C

190C

200C

206C

218C

Con

n. S

ize

In.

YX

ED

CB

AL

SS

ize

Eva

por

ato

rC

ente

r of

Gra

vity

No

te:

Rem

ote

evap

orat

orco

nnec

tions

in th

is lo

catio

n. “X

”

A

34 IOMM ALS-3

Figure 21, Dimensions, ALS 245C –295CNote: See page 11 for lifting locations, mounting locations, weights and mounting loads.

No

tes

:1.

All

dim

ensi

ons

in in

ches

(m

m).

2. O

nly

wat

er c

onne

ctio

ns a

s

s

how

n ar

e av

aila

ble.

8.0

(203

) Vi

ctau

lic C

onne

ctio

nsC

oupl

ings

by

Oth

ers.

Con

trol w

iring

entry

kno

ckou

tsfo

r ½

(13

)co

ndui

t bot

hsi

des

of u

nit.

94.5

(240

0)

6.0

(152

) 65.6

(166

6)

10.0

(256

)

Pow

er e

ntry

loca

tion

this

sid

e on

ly.

2 ad

ditio

nal k

nock

outs

6.0

(15

2)ab

ove

and

belo

w th

is o

peni

ngfo

r m

ultip

le p

ower

sup

ply.

Sta

ndar

d C

oil G

uard

s

28.5

(72

4)

6.50

(1

65)

27.8

(706

)

142.

7 (3

625)

220.

1 (5

590)

Out

let

Inle

tC

ompr

esso

r#1

Com

pres

sor

#2

No

te:

Rem

ote

evap

orat

orco

nnec

tions

in th

is lo

catio

n.

Com

pres

sor

#3

355.

0 (9

017)

Con

trol

Cen

ter

Pow

erC

ente

r

C/G

155

(39

17)

IOMM ALS-3 35

Figure 22, Dimensions, ALS 325C – 420CNote: See page 11 for lifting locations, mounting locations, weights and mounting loads.

36 IOMM ALS-3

Wind Baffles and Hail Guards

Wind Baffles/Hail Guards are a field installed option that is used to stabilize unit operation in high windareas and to assist in operation at low ambient temperatures. Figure 23 is a sketch of a typical panelassembly on an ALS unit. The actual number of panels and parts will vary by model size. The parts areshown in the table below and referenced by balloon numbers.

Figure 23, Installation Sequence

Rib Attachment

RIB FLANGES ON THE ENDMUST POINT TO CENTER

OF COIL TO HAVE A FINISHEDLOOK. INTERIOR RIB FLANGESCAN POINT IN ANY DIRECTION.

ATTACH ALL RIBS TO COIL VERTICAL CHANNELS.

UNIT VERTICAL COIL

Top Attachment

A

B

C

D

E

ATTACH TOP "A" AT HORIZONTALCOIL CHANNEL FIRST. THIS WILL

SQUARE THE PANEL.

ATTACH LEFT SIDE SECOND.LAP PANEL "B" OVER PANEL "A"AND REPEAT ATTACHMENT PROCEDURE.

UNIT VERTICAL COIL

Front Attachment

A

B

C

D

E

HANG FRONT "A" BY TOP FLANGEAND FASTEN AT TOP AND LEFT SIDE.

HANG FRONT "B" BY LAPPINGOVER "A" AND REPEAT ATTACHMENT PROCEDURE.

UNIT VERTICAL COIL

1 3

2

IOMM ALS-3 37

Table 29, Packing ListDescription Part

NumberApplies to Unit Models Bubble

Number

Vertical Support Rib 330228101 134" Top Cover 330228201 234" Front Panel 330228301

171-186, 190-218, 260-295,375-420 3

41" Top Cover 330228401 241" Front Panel 330228501

141-150, 245, 325-3653

¼ - 20 x ½” Screw (Place in Poly Bag) 046093807Packing List and Hail Guard Assembly Sht. 1 & 2 R330228601

Erection Sequence R330229301

Figure 24, Rib, Cover and Panel

VERTICAL SUPPORT RIB TOP COVER FRONT PANEL

38 IOMM ALS-3

Electrical Data

Field Wiring

GeneralWiring must comply with all applicable codes and ordinances. Warranty is voided if wiring is not inaccordance with specifications. An open fuse indicates a short, ground, or overload. Beforereplacing a fuse or restarting a compressor or fan motor, the trouble must be found and corrected.

Copper wire is required for all power lead terminations at the unit and copper must be used for all otherwiring to the unit.

ALS units may be ordered with main power wiring for either single or multiple point power connection.If single point power connection is ordered, a single large power terminal block is provided and wiringwithin the unit is sized in accordance with the National Electrical code. A disconnect is required andcan be furnished as a factory option. The 115 volt control transformer is factory mounted and wired.

If multiple point power wiring is ordered, two power connections (141 through 218 and 325 through420) or three power connections (245 through 295) are required and wiring within the unit is sized inaccordance with the National Electrical Code. A separate circuit is required for the 115 volt controlcircuit. Separate field supplied disconnects are required for each electrical circuit.

It may be desirable to have the unit evaporator heater on a separate disconnect switch from the mainunit power supply so that the unit may be shut down without defeating the freeze protection providedby the cooler heater.

CAUTION

ALS unit compressors are single direction rotation compressors. For this reason proper phasing ofelectrical power is important. Electrical phasing must be A, B, C for electrical phases 1, 2 and 3 (A=L1,B=L2, C=L3) for single or multiple point wiring arrangements. The solid-state starters contain thephase reversal protection. Do not alter the wiring to the starters.

CAUTION

Internal power wiring to the compressors for the single point versus the multiple point option aredifferent. It is imperative that the proper field wiring be installed according to the way the unit is built.

IOMM ALS-3 39

Wire Sizing AmpacitiesTable 30, ALS 141C – ALS 218C, Electrical Data, Single-Point

POWER SUPPLY

FIELD WIRE HUB(Conduit Connection)

FIELD FUSE SIZE orHACR BREAKER SIZE

WIRE NOMINAL RECOM-

ALSUNITSIZE

VOLTS HZ

MINIMUMCIRCUITAMPACITY

(MCA) QTYGAUGE

QTYSIZE MENDED

MAXIMUM

208 609 6 350 2 2.5 700 800230 558 6 300 2 2.5 700 700

141C 380 60 338 3 400 1 3.0 400 450460 278 3 300 1 2.5 350 350575 226 3 4/0 1 2.0 250 300208 686 6 500 2 3.0 800 800230 626 6 400 2 3.0 700 800

150C 380 60 379 3 500 1 3.0 450 500460 313 3 400 1 3.0 350 450575 252 3 250 1 2.5 300 350208 758 6 500 2 3.0 1000 1000230 693 6 500 2 3.0 800 800

171C 380 60 419 6 4/0 See Note 9 2 2.0 500 500460 346 3 500 1 3.0 400 450575 277 3 300 1 2.5 350 350208 813 6 600 2 3.0 1000 1000230 742 6 500 2 3.0 1000 1000

186C 380 60 449 6 4/0 See Note 9 2 2.0 500 600460 370 3 500 1 3.0 450 500575 296 3 350 1 2.5 350 400208 825 6 600 2 3.0 1000 1000230 753 6 500 2 3.0 1000 1000

190C 380 60 456 6 4/0 See Note 9 2 2.0 600 600460 376 3 500 1 3.0 450 500575 301 3 350 1 2.5 350 400208* 869* 6 600* 2 3.0 1000 1200230 792 6 600 2 3.0 1000 1000

200C 380 60 480 6 250 2 2.5 600 600460 395 6 4/0 See Note 9 2 2.0 450 500575 316 3 400 1 3.0 350 400208* 869* 6 600* 2 3.0 1000 1200230 792 6 600 2 3.0 1000 1000

206C 380 60 480 6 250 2 2.5 600 600460 395 6 4/0 See Note 9 2 2.0 450 500575 316 3 400 1 3.0 350 400208* 897* 6 600* 2 3.0 1000 1200230 812 6 600 2 3.0 1000 1000

218C 380 60 489 6 250 2 2.5 600 600460 406 6 4/0 See Note 9 2 2.0 450 500575 326 3 400 1 3.0 400 450

Notes1. Table based on 75°C field wire except (*) which require 90°C field wire.2. A “HACR” breaker is a circuit breaker designed for use on equipment with multiple motors. It stands for Heating, Air Conditioning, Refrigeration.3. Complete notes are on page 57.

40 IOMM ALS-3

Table 31, ALS 245C – ALS 420C, Electrical Data, Single-PointPOWER SUPPLY

FIELD WIRE HUB(Conduit Connection)

FIELD FUSE SIZE orHACR BREAKER SIZE

WIRE NOMINAL RECOM-

ALSUNITSIZE

VOLTSNote (1) HZ

MINIMUMCIRCUITAMPACITY

(MCA) QTYGAUGE

QTYSIZE MENDED

MAXIMUM

380 567 6 300 2 2.0 700 700

245C 460 60 469 6 250 2 2.0 600 600575 377 6 3/0 2 1.5 450 450

380 607 6 350 2 2.5 700 700

260C 460 60 502 6 250 2 2.0 600 600575 402 6 4/0 See Note 9 2 2.0 450 500

380 637 6 400 2 2.5 700 800

270C 460 60 526 6 300 2 2.0 600 600575 421 6 4/0 See Note 9 2 2.0 500 500

380 661 6 400 2 2.5 800 800

275C 460 60 545 6 300 2 2.0 600 700575 436 6 4/0 See Note 9 2 2.0 500 500

380 685 6 500 2 3.0 700 800

295C 460 60 564 6 300 2 2.0 700 700575 451 6 4/0 See Note 9 2 2.0 500 500

380 730 6 500 2 3.0 800 800

325C 460 60 607 6 350 2 2.5 700 700575 490 6 250 2 2.0 600 600

380 763 6 600 2 3.0 800 800

335C 460 60 635 6 400 2 2.5 700 700575 511 6 300 2 2.0 600 600

380 796 6 600 2 3.0 800 800

350C 460 60 663 6 400 2 2.5 700 800575 532 6 300 2 2.0 600 600

380 826 6 600 2 3.0 1000 1000

365C 460 60 687 6 500 2 3.0 800 800575 551 6 300 2 2.0 600 600

380* 866* 6 600* 2 3.0 1000 1000

375C 460 60 720 6 500 2 3.0 800 800575 578 6 350 2 2.5 700 700

380* 890* 6 600* 2 3.0 1000 1000

385C 460 60 739 6 500 2 3.0 800 800575 593 6 350 2 2.5 700 700

380* 914* 6 600* 2 3.0 1000 1000

400C 460 60 758 6 500 2 3.0 800 800575 608 6 350 2 2.5 700 700

380* 948* 6 600* 2 3.0 1000 1000

420C 460 60 782 6 600 2 3.0 800 800575 627 6 400 2 2.5 700 700

NOTES: 1. Table based on 75°C field wire except (*) which require 90°C field wire.2. Single point connections are not available with 208/230 volt power supply.3. A “HACR” breaker is a circuit breaker designed for use on equipment with multiple motors. It stands for Heating, Air Conditioning, Refrigeration.4. Complete notes are on page 57.

IOMM ALS-3 41

Table 32, ALS 141C – ALS 218C, Electrical Data, Multiple-Point

ELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)

POWER SUPPLY FIELD FUSING POWER SUPPLY FIELD FUSING

FIELD WIRE

HUB(Conduit

Connection)

FIELD WIREHUB

(ConduitConnection)

ALSUNITSIZE

VOLTS HZMINIMUMCIRCUIT

AMPS(MCA)

QTYWIRE

GAUGEQTY

HUBSIZE

RECFUSESIZE

MAXFUSESIZE

MINIMUMCIRCUIT

AMPS(MCA)

QTYWIRE

GAUGEQTY

HUBSIZE

RECFUSESIZE

MAXFUSESIZE

208 335 3 400 1 3.0 400 500 335 3 400 1 3.0 400 500

230 307 3 350 1 2.5 400 500 307 3 350 1 2.5 400 500

141C 380 60 186 3 3/0 1 2.0 225 300 186 3 3/0 1 2.0 225 300

460 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

575 124 3 1 1 1.5 150 200 124 3 1 1 1.5 150 200

208 335 6 4/0 2 2.0 400 500 412 6 4/0 2 2.0 500 700

230 307 3 350 1 2.5 400 500 375 3 500 1 3.0 450 600

150C 380 60 186 3 3/0 1 2.0 225 300 227 3 4/0 1 2.0 300 350

460 153 3 2/0 1 1.5 200 250 188 3 3/0 1 2.0 225 300

575 124 3 1 1 1.5 150 200 150 3 1/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600 381 6 3/0 2 2.0 450 600

171C 380 60 230 3 4/0 1 2.0 300 350 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 472 6 250 2 2.5 600 800

230 381 6 3/0 2 2.0 450 600 430 6 4/0 2 2.0 500 700

186C 380 60 230 3 4/0 1 2.0 300 350 260 3 300 1 2.5 350 450

460 191 3 3/0 1 2.0 225 300 214 3 4/0 1 2.0 300 350

575 153 3 2/0 1 1.5 200 250 171 3 2/0 1 1.5 225 250

208 423 6 4/0 2 2.0 500 700 478 6 250 2 2.5 600 800

230 387 6 3/0 2 2.0 500 600 436 6 4/0 SeeNote 9

2 2.0 600 700

190C 380 60 234 3 250 1 2.5 300 400 264 3 300 1 2.5 350 450

460 193 3 3/0 1 2.0 250 300 217 3 4/0 1 2.0 300 350

575 155 3 2/0 1 1.5 200 250 174 3 2/0 1 1.5 225 300

208 478 6 250 2 2.5 600 800 478 6 250 2 2.5 600 800

230 436 6 4/0 2 2.0 600 700 436 6 4/0 SeeNote 9

2 2.0 600 700

200C 380 60 264 3 300 1 2.5 350 450 264 3 300 1 2.5 350 450

460 217 3 4/0 1 2.0 300 350 217 3 4/0 1 2.0 300 350

575 174 3 2/0 1 1.5 225 300 174 3 2/0 1 1.5 225 300

208 478 6 250 2 2.5 600 800 478 6 250 2 2.5 600 800

230 436 6 4/0 SeeNote 9

2 2.0 600 700 436 6 4/0 SeeNote 9

2 2.0 600 700

206C 380 60 264 3 300 1 2.5 350 450 264 3 300 1 2.5 350 450

460 217 3 4/0 1 2.0 300 350 217 3 4/0 1 2.0 300 350

575 174 3 2/0 1 1.5 225 300 174 3 2/0 1 1.5 225 300

208 492 6 250 2 2.5 600 800 492 6 250 2 2.5 600 800

230 445 6 4/0 SeeNote 9

2 2.0 600 700 445 6 4/0 SeeNote 9

2 2.0 600 700

218C 380 60 269 3 300 1 2.5 350 450 269 3 300 1 2.5 350 450

460 223 3 4/0 1 2.0 300 350 223 3 4/0 1 2.0 300 350

575 179 3 3/0 1 2.0 225 300 179 3 3/0 1 2.0 225 300

NOTE:1. Table based on 75°C field wire2. Complete notes are on page 57.

42 IOMM ALS-3

Table 33, ALS 245C – ALS 295C, Circuits # 1 & 2, Electrical Data, Multiple-Point(Circuit #3 on following page)

ELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)


FIELD WIREHUB

(Conduit

Connection)

FIELD WIREHUB

(Conduit

Connection)

WIRE HUB WIRE HUB

ALSUNITSIZE


AMPS(MCA)

QTYGAUGE

QTYSIZE

RECFUSESIZE

MAXFUSESIZE

MINIMUMCIRCUIT

AMPS(MCA)

QTYGAUGE

QTYSIZE

RECFUSESIZE

MAXFUSESIZE

208 335 6 4/0 2 2.0 400 500 417 6 4/0 2 2.0 500 700

230 307 6 3/0 2 2.0 400 500 381 6 3/0 2 2.0 450 600

245C 380 60 186 3 3/0 1 2.0 225 300 230 3 4/0 1 2.0 300 350

460 153 3 2/0 1 1.5 200 250 191 3 3/0 1 2.0 225 300

575 124 3 1 1 1.5 150 200 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600 381 6 3/0 2 2.0 450 600

260C 380 60 230 3 4/0 1 2.0 300 350 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600 381 6 3/0 2 2.0 450 600

270C 380 60 230 3 4/0 1 2.0 300 350 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 472 6 250 2 2.5 600 800

230 381 6 3/0 2 2.0 450 600 430 64/0 SeeNote 9

2 2.0 500 700

275C 380 60 230 3 4/0 1 2.0 300 350 260 3 300 1 2.5 350 450

460 191 3 3/0 1 2.0 225 300 214 3 4/0 1 2.0 300 350

575 153 3 2/0 1 1.5 200 250 171 3 2/0 1 1.5 225 250

208 472 6 250 2 2.5 600 800 472 6 250 2 2.5 600 800

230 430 64/0 SeeNote 9

2 2.0 500 700 430 64/0 SeeNote 9

2 2.0 500 700

295C 380 60 260 3 300 1 2.5 350 450 260 3 300 1 2.5 350 450

460 214 3 4/0 1 2.0 300 350 214 3 4/0 1 2.0 300 350

575 171 3 2/0 1 1.5 225 250 171 3 2/0 1 1.5 225 250

NOTE:1. Table based on 75°C field wire2. Complete notes are on page 57.

IOMM ALS-3 43

Table 33, Electrical Data, ALS 245C – 295C, (Circuit #3)

ELECTRICAL CIRCUIT 3 (COMP 3)

POWER SUPPLY FIELD FUSING

FIELD WIREHUB

(Conduit

Connection)

WIRE HUB

ALSUNITSIZE


AMPS(MCA)

QTYGAUGE

QTYSIZE

RECFUSESIZE

MAXFUSESIZE

208 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600

245C 380 60 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600

260C 380 60 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250

208 472 6 250 2 2.5 600 800

230 430 64/0 SeeNote 9

2 2.0 500 700

270C 380 60 260 3 300 1 2.5 350 450

460 214 3 4/0 1 2.0 300 350

575 171 3 2/0 1 1.5 225 250

208 472 6 250 2 2.5 600 800

230 430 64/0 SeeNote 9

2 2.0 500 700

275C 380 60 260 3 300 1 2.5 350 450

460 214 3 4/0 1 2.0 300 350

575 171 3 2/0 1 1.5 225 250

208 472 6 250 2 2.5 600 800

230 430 64/0 SeeNote 9

2 2.0 500 700

295C 380 60 260 3 300 1 2.5 350 450

460 214 3 4/0 1 2.0 300 350

575 171 3 2/0 1 1.5 225 250

NOTES:1. Table based on 75°C field wire2. Complete notes are on page 57.

44 IOMM ALS-3

Table 34, ALS 325C – ALS 420C, Electrical Data, Multiple-PointELECTRICAL CIRCUIT 1 (COMP 1 & 3) ELECTRICAL CIRCUIT 2 (COMP 2 & 4)


FIELD WIREHUB

(Conduit

Connection)

FIELD WIREHUB

(Conduit

Connection)

WIRE HUB WIRE HUB

ALSUNITSIZE


AMPS(MCA)

QTYGAUGE

QTYSIZE

RECFUSESIZE

MAXFUSESIZE

MINIMUMCIRCUIT

AMPS(MCA)

QTYGAUGE

QTYSIZE

RECFUSESIZE

MAXFUSESIZE

208 706 6 500 2 3.0 800 1000 706 6 500 2 3.0 800 1000

230 640 6 400 2 2.5 800 800 640 6 400 2 2.5 800 800

325C 380 60 386 6 250 1 3.0 450 500 386 6 250 1 3.0 450 500

460 321 3 400 1 2.5 400 450 321 3 400 1 2.5 400 450

575 259 3 300 1 2.0 300 350 259 3 300 1 2.0 300 350

208 706 6 500 2 3.0 800 1000 767 6 600 2 3.0 1000 1000

230 640 6 500 2 3.0 800 800 695 6 500 2 3.0 800 800

335C 380 60 386 6 250 1 3.0 450 500 419 6 300 1 3.0 500 500

460 321 3 400 1 2.5 400 450 349 3 500 1 3.0 400 450

575 259 3 300 1 2.0 300 350 280 3 300 1 2.0 350 350

208 767 6 600 2 3.0 1000 1000 767 6 600 2 3.0 1000 1000

230 695 6 500 2 3.0 800 800 695 6 500 2 3.0 800 800

350C 380 60 419 6 300 1 3.0 500 500 419 6 300 1 3.0 500 500

460 349 3 500 1 3.0 400 450 349 3 500 1 3.0 400 450

575 280 3 300 1 2.0 350 350 280 3 300 1 2.0 350 350

208 767 6 600 2 3.0 1000 1000 822 6 600 2 3.0 1000 1000

230 695 6 500 2 3.0 800 800 744 6 500 2 3.0 1000 1000

365C 380 60 419 6 300 1 3.0 500 500 449 6 300 1 3.0 500 600

460 349 3 500 1 3.0 400 450 373 3 500 1 3.0 450 500

575 280 3 300 1 2.0 350 350 299 3 350 1 2.5 350 400

208 837 6 600 2 3.0 1000 1000 837 6 600 2 3.0 1000 1000

230 758 6 500 2 3.0 800 1000 758 6 500 2 3.0 800 1000

375C 380 60 457 6 350 1 3.5 600 600 457 6 350 1 3.5 600 600

460 380 3 500 1 3.0 450 500 380 3 500 1 3.0 450 500

575 305 3 350 1 2.5 350 400 305 3 350 1 2.5 350 400

208 837 6 600 2 3.0 1000 1000 881 6 600* 2 3.0 1000 1200

230 758 6 500 2 3.0 800 1000 797 6 600 2 3.0 1000 1000

385C 380 60 457 6 350 1 3.5 600 600 481 6 350 1 3.5 600 600

460 380 3 500 1 3.0 450 500 399 6 250 1 3.0 500 500

575 305 3 350 1 2.5 350 400 320 3 400 1 2.5 400 400

208* 881* 6 600* 2 3.0 1000 1200 881* 6 600* 2 3.0 1000 1200

230 797 6 600 2 3.0 1000 1000 797 6 600 2 3.0 1000 1000

400C 380 60 481 6 350 1 3.5 600 600 481 6 350 1 3.5 600 600

460 399 6 250 1 3.0 500 500 399 6 250 1 3.0 500 500

575 320 3 400 1 2.5 400 400 320 3 400 1 2.5 400 400

208* 908* 6 600* 2 3.0 1000 1200 908* 6 600* 2 3.0 1000 1200

230 821 6 600 2 3.0 1000 1000 821 6 600 2 3.0 1000 1000

420C 380 60 498 6 400 1 3.5 600 600 498 6 400 1 3.5 600 600

460 411 6 250 1 3.0 450 500 411 6 250 1 3.0 450 500

575 329 3 400 1 2.5 400 450 329 3 400 1 2.5 400 450

NOTES:1. Table based on 75°C field wire except (*) which require 90°C field wire.2. Complete notes are on page 57.

IOMM ALS-3 45

Table 35, ALS141C – ALS 218C, Compressor and Condenser Fan Motor Amp Draw

RATED LOAD AMPS L R A SOLID-STATE STARTING INRUSH

AMPS PER COMPRESSORALS

UNITSIZE

VOLTS HZCIRCUIT #1 CIRCUIT #2

FANMOTORS

FLA(EACH)

NO OFFAN

MOTORS

FANMOTORS(EACH) CIRCUIT #1 CIRCUIT #2

208 245 245 5.8 10 23.7 735 735230 222 222 5.8 10 21.4 666 666

141C 380 60 135 135 3.4 10 14.4 405 405460 111 111 2.8 10 10.7 333 333575 90 90 2.3 10 11.5 270 270208 245 306 5.8 10 23.7 735 918230 222 277 5.8 10 21.4 666 831

150C 380 60 135 168 3.4 10 14.4 405 504460 111 139 2.8 10 10.7 333 417575 90 111 2.3 10 11.5 270 333208 306 306 5.8 12 23.7 918 918230 277 277 5.8 12 21.4 831 831

171C 380 60 168 168 3.4 12 14.4 504 504460 139 139 2.8 12 10.7 417 417575 111 111 2.3 12 11.5 333 333208 306 350 5.8 12 23.7 918 1050230 277 316 5.8 12 21.4 831 948

186C 380 60 168 192 3.4 12 14.4 504 576460 139 158 2.8 12 10.7 417 474575 111 126 2.3 12 11.5 333 378208 306 350 5.8 14 23.7 918 1050230 277 316 5.8 14 21.4 831 948

190C 380 60 168 192 3.4 14 14.4 504 576460 139 158 2.8 14 10.7 417 474575 111 126 2.3 14 11.5 333 378208 350 350 5.8 14 23.7 1050 1050230 316 316 5.8 14 21.4 948 948

200C 380 60 192 192 3.4 14 14.4 576 576460 158 158 2.8 14 10.7 474 474575 126 126 2.3 14 11.5 378 378208 350 350 5.8 14 23.7 1050 1050230 316 316 5.8 14 21.4 948 948

206C 380 60 192 192 3.4 14 14.4 576 576460 158 158 2.8 14 10.7 474 474575 126 126 2.3 14 11.5 378 378208 350 350 7.8 14 30.5 1050 1050230 316 316 7.2 14 27.6 948 948

218C 380 60 192 192 4.1 14 20.0 576 576460 158 158 3.6 14 13.8 474 474575 126 126 3.0 14 11.5 378 378

NOTE: Complete notes are on page 57.

46 IOMM ALS-3

Table 36, ALS 245C – ALS 295C, Compressor and Condenser Fan Motor Amp Draw

RATED LOAD AMPS SOLID STATE STARTING INRUSH

COMPRESSORS AMPS PER COMPRESSORALS

UNITSIZE

VOLTS HZ

NO. 1 NO. 2 NO. 3

FANMOTORS

FLA(EACH)

NO OFFAN

MOTORS

L R AFAN

MOTORS(EACH) NO. 1 NO. 2 NO. 3

208 245 306 306 5.8 16 23.7 735 918 918

230 222 277 277 5.8 16 21.4 666 831 831245C 380 60 135 168 168 3.4 16 14.4 405 504 504

460 111 139 139 2.8 16 10.7 333 417 417575 90 111 111 2.3 16 11.5 270 333 333

208 306 306 306 5.8 18 23.7 918 918 918230 277 277 277 5.8 18 21.4 831 831 831

260C 380 60 168 168 168 3.4 18 14.4 504 504 504460 139 139 139 2.8 18 10.7 417 417 417

575 111 111 111 2.3 18 11.5 333 333 333

208 306 306 350 5.8 18 23.7 918 918 1050

230 277 277 316 5.8 18 21.4 831 831 948270C 380 60 168 168 192 3.4 18 14.4 504 504 576

460 139 139 158 2.8 18 10.7 417 417 474575 111 111 126 2.3 18 11.5 333 333 378

208 306 350 350 5.8 18 23.7 918 1050 1050230 277 316 316 5.8 18 21.4 831 948 948

275C 380 60 168 192 192 3.4 18 14.4 504 576 576460 139 158 158 2.8 18 10.7 417 474 474

575 111 126 126 2.3 18 11.5 333 378 378

208 350 350 350 5.8 18 23.7 1050 1050 1050

230 316 316 316 5.8 18 21.4 948 948 948295C 380 60 192 192 192 3.4 18 14.4 576 576 576

460 158 158 158 2.8 18 10.7 474 474 474575 126 126 126 2.3 18 11.5 378 378 378


IOMM ALS-3 47

Table 37, ALS 325C – ALS 420C, Compressor and Condenser Fan Motor Amp DrawRATED LOAD AMPS SOLID STATE STARTING INRUSH

COMPRESSORS AMPS PER COMPRESSORALS

UNITSIZE

VOLTS HZ

NO 1 NO 2 NO 3 NO 4

FANMOTORS

FLA(EACH)

NO OFFAN

MOTORS

L R AFAN

MOTORS(EACH) NO 1 NO 2 NO 3 NO 4

208 245 245 306 306 7.8 20 30.5 735 735 918 918230 222 222 277 277 7.2 20 27.6 666 666 831 831

325C 380 60 135 135 168 168 4.1 20 20.0 405 405 504 504460 111 111 139 139 3.6 20 13.8 333 333 417 417

575 90 90 111 111 3 20 11.5 270 270 333 333

208 245 306 306 306 7.8 20 30.5 735 918 918 918

230 222 277 277 277 7.2 20 27.6 666 831 831 831335C 380 60 135 168 168 168 4.1 20 20.0 405 504 504 504

460 111 139 139 139 3.6 20 13.8 333 417 417 417575 90 111 111 111 3 20 11.5 270 333 333 333

208 306 306 306 306 7.8 20 30.5 918 918 918 918230 277 277 277 277 7.2 20 27.6 831 831 831 831

350C 380 60 168 168 168 168 4.1 20 20.0 504 504 504 504460 139 139 139 139 3.6 20 13.8 417 417 417 417

575 111 111 111 111 3 20 11.5 333 333 333 333

208 306 306 306 350 7.8 20 30.5 918 918 918 1050

230 277 277 277 316 7.2 20 27.6 831 831 831 948365C 380 60 168 168 168 192 4.1 20 20.0 504 504 504 576

460 139 139 139 158 3.6 20 13.8 417 417 417 474575 111 111 111 126 3 20 11.5 333 333 333 378

208 306 306 350 350 7.8 24 30.5 918 918 1050 1050230 277 277 316 316 7.2 24 27.6 831 831 948 948

375C 380 60 168 168 192 192 4.1 24 20.0 504 504 576 576460 139 139 158 158 3.6 24 13.8 417 417 474 474

575 111 111 126 126 3 24 11.5 333 333 378 378

208 306 350 350 350 7.8 24 30.5 918 1050 1050 1050

230 277 316 316 316 7.2 24 27.6 831 948 948 948385C 380 60 168 192 192 192 4.1 24 20.0 504 576 576 576

460 139 158 158 158 3.6 24 13.8 417 474 474 474575 111 126 126 126 3 24 11.5 333 378 378 378

208 350 350 350 350 7.8 24 30.5 1050 1050 1050 1050230 316 316 316 316 7.2 24 27.6 948 948 948 948

400C 380 60 192 192 192 192 4.1 24 20.0 576 576 576 576460 158 158 158 158 3.6 24 13.8 474 474 474 474

575 126 126 126 126 3 24 11.5 378 378 378 378

208 350 350 350 350 10.0 24 48.1 1050 1050 1050 1050230 316 316 316 316 9.2 24 43.5 948 948 948 948

420C 380 60 192 192 192 192 5.5 24 26.4 576 576 576 576460 158 158 158 158 4.6 24 21.8 474 474 474 474575 126 126 126 126 3.8 24 17.4 378 378 378 378


48 IOMM ALS-3

Table 38, ALS 141C – ALS 218C, Customer Wiring Information With Single-Point Power

WIRING TO STANDARD UNIT POWER BLOCK WIRING TO OPTIONAL NONFUSEDDISCONNECT SWITCH IN UNITALS

UNITSIZE

VOLTS HZTERMINAL SIZE

AMPS

CONNECTOR WIRE RANGEPER PHASE

(COPPER WIRE ONLY)SIZE


(COPPER WIRE ONLY)

208 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM230 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM

141C 380 60 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM460 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM575 840 (2) 2 to 600 MCM 250 (1) 4 to 350 MCM208 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM230 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM

150C 380 60 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM460 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM575 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM208 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM230 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM






218C 380 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM460 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM575 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM

NOTE:1. Terminal size amps are the maximum amps that the power block is rated for.2. Complete notes are on page 57.

IOMM ALS-3 49

Table 39, ALS 245C – ALS 420C, Customer Wiring Information, Single-Point Power

WIRING TO STANDARD UNIT POWER BLOCK WIRING TO OPTIONAL NONFUSEDDISCONNECT SWITCH IN UNITALS

UNITSIZE

VOLTS HZTERMINAL SIZE

AMPS


(COPPER WIRE ONLY)SIZE


(COPPER WIRE ONLY)

380 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM245C 460 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM

575 840 (2) 2 to 600 MCM 400 (2) 3/0 to 250 MCM380 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM

260C 460 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM575 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM380 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM

270C 460 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM575 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM380 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM


295C 460 60 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM575 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM380 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM





375C 460 60 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM575 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM380 950 (2) 2 to 750 MCM 1200 (3) 500 to 750 MCM



420C 460 60 840 (2) 2 to 600 MCM 1200 (3) 500 to 750 MCM575 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM

NOTE:1. Terminal size amps are the maximum amps that the power block is rated for.2. Complete notes are on page 57.

50 IOMM ALS-3

Table 40, ALS 141C – ALS 218C, Wiring Information with Multiple-Point Power w/o DisconnectWIRING TO UNIT POWER BLOCK

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)ALSUNITSIZE

VOLTS HZCKT 1 CKT 2 CKT 1 CKT 2

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

141C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM


208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM150C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

171C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

186C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

190C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

200C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

206C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

218C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM


NOTES:1. Terminal size amps are the maximum amps that the power block is rated for.2. See Table 43 for multiple point with Disconnect Switch connections3. Complete notes are on page 57.

IOMM ALS-3 51

Table 41, ALS 245C – ALS 295C, Customer Wiring Information, Multiple-Point Power w/o DisconnectWIRING TO UNIT POWER BLOCK

TERMINBAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)ALS UNIT

SIZEVOLTS HZ

CKT 1 CKT 2 CKT 3 CKT 1 CKT 2 CKT 3

208 840 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM (2) #2 to 600 MCM


245C 380 60 840 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM (2) #2 to 600 MCM
























52 IOMM ALS-3

Table 42, ALS 325C – 420C, Customer Wiring Information, Multiple-Point Power w/o DisconnectWIRING TO UNIT POWER BLOCK

POWER BLOCK

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)UNITSIZE

VOLTS HZELEC CIRC #1 ELEC CIRC #2 ELEC CIRC #1 ELEC CIRC #2

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

325C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM








375C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM



385C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 950 950 (2) #2 to 750 MCM (2) #2 to 750 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

400C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 950 950 (2) #2 to 750 MCM (2) #2 to 750 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

420C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM


IOMM ALS-3 53

Table 43, ALS 141C –218C, Wiring Data with Multiple-Point Power w/ Disconnect SwitchWIRING TO UNIT DISCONNECT SWITCH

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)ALSUNITSIZE

VOLTS HZCKT 1 CKT 2 CKT 1 CKT 2

208 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM230 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

141C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0

460 150 150 (1) 4 to 4/0 (1) 4 to 4/0575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM

230 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM150C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0

460 150 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM

230 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM

171C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

230 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

186C 380 60 225 250 (1) 4 to 4/0 (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 225 (1) 4 to 4/0 (1) 4 to 4/0

208 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

230 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

190C 380 60 225 250 (1) 4 to 4/0 (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

200C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

206C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

218C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

NOTE:1. Terminal size amps are the maximum amps that the disconnect switch is rated for.2. Complete notes are on page 57.

54 IOMM ALS-3

Table 44, ALS 245C – 295C, Customer Wiring, Multiple-Point Power w/ Disconnect SwitchWIRING TO UNIT DISCONNECT SWITCH

TERMINBAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)ALS UNIT

SIZEVOLTS HZ

CKT 1 CKT 2 CKT 3 CKT 1 CKT 2 CKT 3

208 400 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM


245C 380 60 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

460 150 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 150 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0



260C 380 60 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

460 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 150 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

208 400 400 600 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM (2) 250 to 350 MCM

230 400 400 600 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM (2) 250 to 350 MCM

270C 380 60 225 225 250 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 350 MCM

460 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

208 400 600 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM (2) 250 to 350 MCM

230 400 600 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM (2) 250 to 350 MCM

275C 380 60 225 250 250 (1) 4 to 4/0 (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

575 150 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM (2) 250 to 350 MCM

295C 380 60 250 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

575 225 225 225 (1) 4 to 4/0 (1) 4 to 4/0 (1) 4 to 4/0

NOTES:1. Terminal size amps are the maximum amps that the disconnect switch is rated for.2. Complete notes are on page 57.

IOMM ALS-3 55

Table 45, ALS 315C – 420C, Customer Wiring Data, Multiple-Point Power w/Disconnect SwitchWIRING TO UNIT DISCONNECT SWITCH

POWER BLOCK

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)UNITSIZE VOLTS HZ

ELEC CIRC 1 ELEC CIRC 2 ELEC CIRC 1 ELEC CIRC 2

208 800 800 (2) 500 to 700 MCM (2) 500 to 700 MCM

230 800 800 (3) 3/0 to 400 MCM (3) 3/0 to 400 MCM

325C 380 60 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM460 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM


335C 380 60 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM460 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM


350C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM460 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM


365C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM460 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM


375C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM



385C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM460 400 600 (1) 250 to 500 MCM (2) 250 to 350 MCM

575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

208 1200 1200 (3) 500 to 750 MCM (3) 500 to 750 MCM

230 1200 1200 (3) 500 to 750 MCM (3) 500 to 750 MCM

400C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

460 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

208 1200 1200 (3) 500 to 750 MCM (3) 500 to 750 MCM

230 1200 1200 (3) 500 to 750 MCM (3) 500 to 750 MCM

420C 380 60 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

460 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

575 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

NOTES:1. Terminal size amps are the maximum amps that the disconnect switch is rated for.2. Complete notes are on page 57.

56 IOMM ALS-3

Electrical Data Notes1. Allowable voltage limits

Unit nameplate 208V/60Hz/3PH: 187V to 229VUnit nameplate 230V/60Hz/3Ph: 207V to 253VUnit nameplate 380V/60Hz/3Ph: 342V to 418VUnit nameplate 460V/60Hz/3Ph: 414V to 506VUnit nameplate 575V/60Hz/3Ph: 517V to 633V

2. Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100% of RLA of allother loads in the circuit including control transformer. Wire size ampacity for separate 115V control circuitpower is 15 amps for ALS 141C through ALS 295C.

3. Compressor RLA values are for wire sizing purposes only but do reflect normal operating current draw at unitrated capacity. If unit is equipped with SpeedTrol condenser fan motors, the first motor on each refrigerantcircuit is a single phase, 1 hp motor, with a FLA of 2.8 amps at 460 volts (5.6 amps at 208/230 volts). If the unitis not equipped with SpeedTrol, the standard fan motor will be 1 1/2 hp, 3-phase ODP (for ALS 141C-295Cexcept ALS 218C which will be 2 hp, 3-phase TEFC ) with FLA as shown in the electrical tables. For ALS 325C-400C the standard TEFC fan motor will be 2 hp, 3-phase and for ALS 420C fan motor will be 2.5 hp, 3-phase.

4. Single point power supply requires a single disconnect to supply electrical power to the unit. The disconnectdevice may be in the unit as an option or supplied and installed in the field within sight of the unit. Thepower supply must be fused or have a HACR Type breaker.

5. Multiple point power supply requires two independent power circuits on ALS 141C-ALS 218C, ALS 325C-ALS420C and three independent power circuits on ALS 245C-ALS 295C. The disconnect devices may be in theunit as an option or supplied and installed in the field within sight of the unit. The power supplies must befused or have a HACR Type breaker.

6. All field wiring to unit power block or optional nonfused disconnect switch must be copper.

7. Field wire size values given in tables apply to 75°C rated wire per NEC except for ALS 200C-ALS 218C for 208Vsingle point, ALS 375C-ALS 420C for 380V single point, and ALS 400C-ALS420C for 208V multi-pointapplication which require 90°C rated wire or as noted.

8. If unit is to be factory supplied with the optional non-fused disconnect switch, the recommended field wiresize needs to be (6) 250MCM wire in place of the standard (6) 4/0 wire to match the disconnect switch terminallug size which is approved for 250MCM minimum.

9. External disconnect switch(s) or HACR breakers must be field supplied. Note: On single point power units anon-fused disconnect switch in the cabinet is available as an option.

10. All wiring must be done in accordance with applicable local and national codes.

11. Recommended time delay fuse size or HACR circuit breakers is equal to 150% of the largest compressor motorRLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

12. Maximum time delay fuse size or HACR circuit breakers is equal to 225% of the largest compressor-motor RLAplus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

13. MCA may vary slightly due to fan motor options such as Speedtrol, TEFC.

IOMM ALS-3 57

Table 46, Electrical Legend

58 IOMM ALS-3

Field Wiring Diagram

Figure 25, Typical Field Wiring Diagram

IOMM ALS-3 59

Solid State Starters

Solid state starters are standard on all "C" Vintage ALS units. A solid state starter, by definition, is aunit that by the use of a silicon controlled rectifier (SCR) power section allows a motor to be broughtto full speed by way of a reduced initial voltage that increases to full line voltage over a given time.The McQuay motor starter, custom designed for this specific application, is a microprocessor-controlled solid state starter. Along with this starting technique, the motor starter also providesprotection for the motor and monitors its load conditions.

The starter offers:

• Solid state design.

• Closed-loop motor current control.

• Programmable motor protection.

• Programmable operating parameters.

• Programmable metering options.

The three-phase starter contains a six SCR power section with two SCRs per phase connected ininverse parallel. This power section is capable of providing maximum torque per amp throughout themotor’s speed-torque curve with minimal motor and starter heating. At the same time, the startercontinually monitors the amount of current being delivered to the motor, thus protecting the motorfrom overheating or drawing excessive current. The starter will automatically stop the motor if theline-to-line current is not within acceptable ranges or if the current is lost in a line. The motor currentscaling is set according to the motor size and the specific application. The starter circuitry iscontained on a single printed circuit board, which contains all the logic and SCR gate drive circuitry.

Operating messages are displayed on the three-character LED display on the control card. The LEDdisplay on the control card displays:

• Operating messages that indicate the status of the motor and/or starter.

• Operating parameters that are programmed into the starter.

• Fault codes that indicate a problem with the motor application or starter.

Operating MessagesPossible operating messages are as follows:

Message MeaningnoL Line voltage is not present.

rdy Line voltage is present and starter is ready.

acc Motor is accelerating after a start command has been received.

uts The motor has achieved full speed.

run Motor is operating at full speed, and ramp time has expired.

dCL A Stop command was received and the motor is decelerating with the setdeceleration profile.

OL OL will alternately blink with the normal display on the LED display whenmotor thermal overload content has reached 90% to 99% of its capacity.

60 IOMM ALS-3

OLL The motor thermal overload content has reached 100%, and the motor hasstopped. The motor cannot be restarted until the overloaded motor hascooled and OLt is displayed.

OLt The motor thermal overload content has been reduced to 60% or less, andthe motor may be restarted.

ena Passcode protection is enabled.

dis Passcode is disabled.

oxx xx = overload thermal content in percentage. Press the Down button totoggle to this display.

cxx xx = pending fault.

no Attempted to change a passcode protected parameter.

… Three decimal places blink when remote display is active.

Fault CodesFault codes will be displayed on the red, three-character LED display. Fault codes indicate a problemwith the starter or motor application.

CODE FAULT

F1 Power line phase sensitivity parameter set to ABC for CBA line sequence.

F2 Power line phase sensitivity parameter set to CBA for ABC line sequence.

F3 System power is not three phase.

F4 System power is not single phase.

F5 Line frequency is less than 25hz.

F6 Line frequency is greater than 72 hz.

F11 Line sequence has changed since last start.

F16 Excessive line noise.

F17 Extreme line noise.

F23 Line current imbalance is greater than set current imbalance level.

F24 Line current became very unbalanced while the motor was running.

F29 Operating parameters have been lost.

F30 Three phase default parameters have been loaded.

F31 Single phase default parameters have been loaded.

F52 A motor current greater than 12.5% was detected while the motor was stopped.

F53 No current detected after “Run” command was given.

IOMM ALS-3 61

F54 An undercurrent trip has occurred.

F55 An overcurrent trip has occurred.

F70 Control power is too low.

F71 Motor current transformer scaling switches were changed while the motor was running.

F73 Bypass failed to operate when unit came up to speed.

F74 The motor stalled while accelerating.

F75 External fault.

F77 Control card fault.


F90 Incorrect set-up.

F92 A shorted SCR was detected during acceleration.


F98 Line power was missing when Start command was given or while starter was operatingthe motor.

F99 Load current very high.

Preventative MaintenanceDuring Commissioning;• Torque all power connections during commissioning. This includes factory wired components.• Check all of the control wiring in the package for loose connections.

During the first month after the starter has been put in operation;• Re-torque all power connections every two weeks. This includes factory-wired components.• Inspect cooling fans (if applicable) after two weeks to ensure proper operation.

After the first month of operation;• Re-torque all power connections every year.• Clean any accumulated dust from the starter using a clean source of compressed air.• Inspect the cooling fans (if applicable) every three months to ensure proper operation.• Clean or replace any air vent filters on the starter every three months.

NOTE: If mechanical vibrations are present at the installation site, inspect the connections morefrequently.

62 IOMM ALS-3

Figure 26, Trouble Shooting Guide

L o w or M is sin gL in e ?

P h a s e O rd e rFa u lt

Therma l Trip?

InterlockOpen?

Wiring OK?High

Ambient?

In-Line OK?

CircuitBreaker OK?

Fuses OK?

Does ProblemSti ll Exis t

Bad AirCirculation?

MotorOverloaded?

Wiring OK?

Swap Any2 PowerLeads

Correct andWait to Cool

ReplaceControl Card

Lower MotorLoad

Correct andWait to Cool

CorrectWir ing

Return ToService

ReplaceCircuitBreaker

ReplaceFuses

Correc tInline Fault

CorrectInterlock

State

Correct PowerSource

Problem

CorrectWiring

No

Yes

Yes

No

No

No

No

No

No

No

Yes

Yes

Yes

No

NoYes

Yes No

NoYes

Yes Yes

Yes

Yes

Yes

No

Return ToService

3

4

Start

5

6

7 8

9

10

7

1

2

Goto Page 2

IOMM ALS-3 63

CurrentImbalance Fault?

Wiring Good?

SCRs OK?

MotorWinding Short?

All GatePulses Present?

ReplaceControl Card

Return to Normal

Operation

Yes

Yes Yes

No

Yes Yes

No Yes

Yes

No

No

No

Yes

Yes

No

No

No

No

Motor Problem?

Repair orReplace Motor

ContactBenshaw

For Assistance

ReplaceControl Card

Check JumpersParameters

and CTs

Correct Wiring

ReplaceDefective SCRs

Does ProblemStill Exist?

ContactBenshaw

For Assistance

CT BurdenSwitches SetCorrectly?

Fuses Blown orBreaker Tripped?

Replace Fuse or Reset Breaker

From Page 1

11

7

12

13

14

12

15

64 IOMM ALS-3

FLOWCHART DETAILS:

1. Fuses Determine if power line fuses have been installed, and if they areoperating properly.

2. Circuit Breaker Determine if the circuit breaker is off, or has tripped anddisconnected the line from the starter.

3. Power Line Voltage Verify that line voltage is present, and is the correct voltage.

4. Phase Order Fault If Fault Codes F1 or F2 are displayed on the control card LED

display exchange any two incoming power line cableconnections.

5. Heat Sink Switch Investigate whether heat sink thermal switch is open.

6. Safety Device Determine if a equipment protection device attached to thestarter is disabling the start command.

7. Wiring Connections Verify that the wiring connections are correct and theterminations are tightened.

8. Air Temperature Investigate whether the air temperature surrounding the heatsink is hot.

9. Air Circulation Determine if the airflow around the heat sink fins is beingrestricted, or if a fan has failed.

10. Motor Overload Determine if the motor’s load is too large for the motor size.

11. Current Imbalance Fault If Fault Codes F23 or F24 are displayed on the control card LEDdisplay, diagnose and correct the cause of the current imbalanceparameter P16.

12. Motor Winding Problem Conducting a megger test of the motor may identify an internalmotor winding problem. NOTE: To avoid damaging the starterisolate the motor before conducting the megger test.

CAUTION:

Hazardous voltages exist at the starter terminals. LOCK OUT ALL OF THE POWER SOURCES beforemaking resistance measurements to avoid personal injury

13. SCRs This step may help determine if a problem exists with the SCRs.Using a multi-meter or similar device, measure the resistancebetween:

• L1 terminal and T1 terminal



The resistance should be more than 50k ohms. Measure the gateresistance between the white and red of each twisted pair (6total). The gate resistance should be between 8 and 50 ohms .

14. Gate Pulses This step may help to determine if the control card is functioningproperly. Check for gate firing voltage between 0.3 and 1.5 voltswhen the card is operating.

15. Motor Current Determine if motor current signal scaling is correct.

IOMM ALS-3 65

Solid State Starter Settings

Operating ParametersParameter Description Default Programmed

P1.....................Motor Full Load Amps............... .......................1 Amp................

P2.....................Motor Service Factor.................. ......................... 1.25..................

P3.....................Motor Thermal Overload ........... ......................Class 10..............

P4.....................Initial Motor Starting Current.... ........................225%.................

P6.....................Motor Ramp Time ....................... ....................7 seconds ............

P7.....................Motor Stall Time.......................... ...................10 seconds ...........

P8.....................Deceleration Level 1 ................... ........................100%.................

P9.....................Deceleration Level 2 ................... ..........................0%...................

P10...................Deceleration Time ....................... ....................2 seconds ............

P11...................Overcurrent Trip Level............... ........................140%.................

P12...................Overcurrent Trip Time ................ ....................2 seconds ............

P13...................Undercurrent Trip Level............. .........................25%..................

P14...................Undercurrent Trip Time.............. ..........................Off...................

P15...................Line Phasing Sensitivity ............ .........................ABC.................

P16...................Motor Current Imbalance........... .........................10%..................

P17...................Current Transformer Ratio .........(460Volt)...........864 .................. (208Volt) ........ 2.64

P18...................Meter Mode................................. ...........................10 ...................

P19...................Meter Dwell Time ........................ ..........................Off...................

P20...................Passcode ...................................... ..........................Off...................

P21...................Auto Reset Capability................ ..........................Off...................

66 IOMM ALS-3

Unit Layout and Principles of Operation

Major Component LocationFigure 27, ALS 141-218

OutletInletCompressor#1

Compressor#2

Con

trol C

ente

rC

ontro

l Cen

ter

CondFan11

CondFan12

CondFan13

CondFan14

CondFan15

CondFan16

CondFan17

CondFan21

CondFan22

CondFan23

CondFan24

CondFan25

CondFan26

CondFan27

10 Fans ALS 141-150C



Figure 28, ALS 245-295

Condenser Circuit #1

OutletInletCompressor#1

Compressor#2

Compressor#3

Con

trol C

ente

r CondFan11

CondFan12

CondFan13

CondFan14

CondFan15

CondFan31

CondFan33

CondFan21

CondFan22

CondFan23

CondFan24

CondFan25

CondFan32

CondFan34

CondFan35

CondFan36

Con

trol C

ente

r




10 Fans ALS 245C


6 Fans ALS 245C

6 Fans ALS 260-295C

IOMM ALS-3 67

Figure 29, ALS 325-420


CondFan11

CondFan12

CondFan13

CondFan14

CondFan15

CondFan16

CondFan21

CondFan22

CondFan23

CondFan24

CondFan25

CondFan26

CondFan31

CondFan32

CondFan33

CondFan34

CondFan35

CondFan36

CondFan41

CondFan42

CondFan43

CondFan44

CondFan45

CondFan46


Condenser Circuit #2 Condenser Circuit #4





Control CenterAll electrical controls are enclosed in a weather resistant control center with keylocked, hinged accessdoors. The control center is composed of two separate compartments, high voltage and low voltage.All of the high voltage components are located in the compartment on the right side of the unit.

The low voltage components are located on the left side with the 115 VAC terminals located behindthe deadfront panel. This protects service personnel from 115 VAC terminals when accessing theadjustable and resettable controls.

68 IOMM ALS-3

Figure 30, Control Center Layout, ALS 141C-218C

K E Y P A D

A O X E X V

L O W V O L T A G E W I R E W A Y

M C B 1 A01

MO

DEM

T B 4 T B 5



LOW

VO

LTA

GE W

IREW

AY

F1 C0 F2

MECH. RELAYS

SC

T 4

T 8

T 2

T 7

NB

RE

SI


M32

M11 M13 M14 M15 M25

M21 M23 M24

M31

M12

M22

M35

T10

M33 M34

FB12

FB7

FB6

FB8

FB9

FB10

FB11

FB13

FB14

CB1 CB2 CB3

CT1

PB1

GRD

KEYPAD

HIGH VOLTAGE WIREWAY

082

EXX01 EXX02

AOX OIOX

LOW VOLTAGE WIREWAY

MCB 280 A01

MO

DE

M

TB4 TB5

LOW VOLTAGE WIREWAY

SC1 SC2 SC3

RES

1

RES

2

RE

S3

LOW VOLTAGE WIREWAY

LOW

VO

LTA

GE

WIR

EW

AY

TB6

F1 C0 F2

MECH. RELAYS

OUTPUTBOARD

TB

3TB

2

T4

T8

T6

T2

T7

NB

CT3CT2

FB5

T1

IOMM ALS-3 69


FB12

FB13

FB14

FB15

FB17

M31 M41 M32 M42 M33 M35 M45

FB7

FB8

FB9

FB10

FB11 M34

M11 M12 M13 M14 M15 M44

M21 M22 M23 M24 M25

CB1 CB3 CB2 CB4

PVM

CT1 CT2

FBT1

PB1

C31

C41

SC31

SC41

TB6

AOX DIOX DIC

CB

NB

RELAYS

RELAYS

MCB280

MO

DE

M

ADI

TB2

TB3

TB4 TB5

RE

S1

RE

S2

SC SC

T4

T8

T6

T2

T7

WIREWAY

WIREWAY

WIREWAYWIREWAY

WIREWAY

WIR

EW

AY

WIR

EW

AY

EXVB1 EXVB2

OUTPUT BOARD 2

OU

TPU

T B

OAR

D 1

SpeedTrol Optional

MHP

R1

MH

PR2

MH

PR3

MH

PR4

T10

M45

70 IOMM ALS-3

Sequence of OperationThe following sequence of operation is typical for McQuay models ALS chillers. The sequence mayvary depending on the software revision or various options which may be installed on the chiller.

Off conditionsWith power supplied to the unit, 115 VAC power is applied through the control fuse F1 to thecompressor heaters (HTR1, HTR2, HTR3, HTR4 and evaporator heater) and the primary of the 24Vcontrol circuit transformer. Note: Compressor heaters must be on for at least 12 hours prior to start-up. The 24V transformer provides power to the MicroTech controller and related components. With24V power applied, the controller will check the position of the front panel system switch. If theswitch is in the "stop" position the chiller will remain off and the display will indicate the operatingmode to be OFF: System Sw. The controller will then check the pumpdown switches. If any of theswitches are in the "stop" position, that circuit’s operating mode will be displayed as OFF:PumpDwnSw. If the switches for both circuits are in the "Stop" position the unit status will displayOFF: PumpdownSw’s. If the remote start/stop switch is open the chiller will be OFF: RemoteSw. Thechiller may also be commanded off via communications from a separate communicating panel such asthe Remote Monitoring and Sequencing Panel or an Open Protocol interface. The display will showOFF: RemoteComm if this operating mode is in effect. If an alarm condition exists which preventsnormal operation of both refrigerant circuits, the chiller will be disabled and the display will indicateOFF: Alarm. If the control mode on the keypad is set to "Manual Unit Off," the chiller will bedisabled and the unit status will display OFF: ManualMode. Assuming none of the above stopconditions are true, the controller will examine the internal time schedule to determine whether thechiller should be permitted to start. The operating mode will be OFF: TimeClock if the time scheduleindicates time remaining in an "off" time period.

AlarmThe alarm light on the front panel will be illuminated when one or more of the cooling circuits has anactive alarm condition which results in the circuit being locked out. Unless the alarm condition affectsall circuits the remaining circuits will operate as required. Refer to IM ALSMICRO for details.

Start-upIf none of the above "off" conditions are true, the MicroTech controller will initiate a start sequenceand energize the chiller water pump output relay. The chiller will remain in the WaitForFlow mode untilthe field installed flow switch indicates the presence of chilled water flow. If flow is not proven within30 seconds, the alarm output will be turned on, the keypad display will be WaitForFlow and the chillerwill continue to wait for proof of chilled water flow. Once flow is established, the controller will samplethe chilled water temperature and compare it against the Leaving Chilled Water Set Point, the ControlBand, and the Start-up Delta Temperature, which have been programmed into the controller’s memory.If the leaving chilled water temperature is above the Leaving Chilled Water Set Point plus ½ the ControlBand plus the adjustable Start-up Delta Temperature, the controller will select the refrigerant circuitwith the lowest number of starts as the lead circuit and energize the first stage of the Cool Stagingmode. The controller will start the compressor and energize the compressor liquid injection solenoidalong with the main liquid line solenoid. The controller will delay the opening of the electronicexpansion valve until the evaporator pressure decreases to a preset value. This is the evaporatorprepurge mode and the display will show Pre-Purge. The valve will then open allowing refrigerant toflow through the expansion valve and into the evaporator and the display will show Opened EXV. Ifadditional cooling capacity is required, the controller will energize the additional cooling capacity byactivating the first compressor’s capacity control solenoids. As the system load increases, thecontroller will start the lag refrigerant circuit in the same manner after interstage timers are satisfied.The compressors and capacity control solenoids will automatically be controlled as required to meetthe cooling needs of the system. The electronic expansion valves are operated by the MicroTechcontroller to maintain precise refrigerant control to the evaporator at all conditions.

IOMM ALS-3 71

Condenser ControlThe first condenser fan stage will be started along with the first compressor to provide initialcondenser head pressure control. The MicroTech controller will activate the remaining condenserfans as needed to maintain proper condenser pressure. The MicroTech controller continuouslymonitors the condenser minus evaporator lift pressure and will adjust the number of operatingcondenser fans as required. The number of condenser fans operating will vary with outdoortemperature and system load. The condenser fans are matched to the operating compressors so thatwhen a compressor is off all fans for that circuit will also be off. On units with the fan speed controloption (SpeedTrol) the lead fan on each circuit will vary in speed to maintain condenser pressure atlower outdoor temperatures.

PumpdownAs the system chilled water requirements diminish. The compressors will be unloaded. As the systemload continues to drop, the electronic expansion valves will be stepped closed and the refrigerantcircuits will go through a pumpdown sequence. As the evaporator pressure falls below thepumpdown pressure set point while pumping down, the compressor(s) and condenser fans will stop.The unit has a one time pumpdown control logic; therefore, if the evaporator pressure rises while therefrigerant circuit is in a pumpdown mode, the controller will not initiate another pumpdown sequence.The controller will keep the unit off until a call for cooling occurs. Refer to the pumpdown controlsection in the current version of OM ALSMICRO for additional details. The chilled water pumpoutput relay will remain energized until the time schedule’s "on" time expires, the remote stop switch isopened, the system switch is moved to the stop position, or a separate communications panel such asthe Remote Monitoring and Sequencing Panel or an Open Protocol interface deactivates the chilledwater pump output.

WARNING

The screw compressor must not be used as a pump out compressor for service work involvingremoval of refrigerant from the compressor or evaporator. That is, the compressor must not be runwith the liquid line valve (king valve) closed. Portable recovery equipment must be used to removethe refrigerant.

Figure 33, ALS Piping Schematic

72 IOMM ALS-3

Start-up and Shutdown

NOTICE

McQuayService personnel or authorized service agencymust perform initial start-up.

CAUTION

Most relays and terminals in the unit control center are powered when S1 is closed and the controlcircuit disconnect is on. Therefore do not close S1 until ready for start-up.

Seasonal Start-upNote: PS1, PS2, PS3, and PS4 will vary depending on the number of circuits.

1. Double check that the compressor suction and discharge shutoff valves are backseated. Alwaysreplace valve seal caps.

2. Insure that the ball valves are open on the lines entering the evaporator.

3. Insure that the manual liquid line shutoff valve at the outlet of the subcooler is open.

4. Adjust the leaving chilled water temperature set point on the MicroTech controller to the desiredchilled water temperature. The control band is preset for 10 degrees Delta-T between the enteringand leaving evaporator water temperature at full load. If the Delta-T is outside an 8°-12°F range,at full load, reset the control band as per the instructions found in the MicroTech Manual IMALSMICRO.

5. Start the auxiliary equipment for the installation by turning on the time clock, and/or remote on/offswitch, and chilled water pump.

6. Check to see that pumpdown switches PS1, PS2, PS3 and PS4 are in the "Pumpdown and Stop"(open) position. Throw the S1 switch to the "auto" position.

7. Under the "Control Mode" menu of the keypad place the unit into the automatic cool mode.

8. Start the system by moving pumpdown switch PS1 to the "auto" position.

9. After running circuit #1 for a short time, check for flashing in the refrigerant sightglass understable conditions.

10. Repeat steps 8 and 9 for PS2, PS3 and PS4 and the second, third and fourth refrigerant circuits.

11. Superheat is factory adjusted to maintain between 6° and 12°F.

CAUTION

The superheat should be between 6°F and 12°F, with the liquid line sightglass full, once the systemtemperatures have stabilized at the MicroTech set point temperatures.

Temporary ShutdownMove pumpdown switches PS1, PS2, PS3 and PS4 to the "Pumpdown and Stop" position. After thecompressors have pumped down, turn off the chilled water pump. Caution: Do not turn the unit offusing the "S1" switch, without first moving PS1, PS2, PS3 and PS4 to the "Stop" position, unless it isan emergency as this will prevent the unit from going through a pumpdown.

IOMM ALS-3 73

IMPORTANT

The unit has one time pumpdown operation. When PS1, PS2, PS3 and PS4 are in the "Pumpdown andStop" position the unit will pumpdown once and not run again until the PS1, PS2, PS3 and PS4switches are moved to the auto position. If PS1, PS2, PS3 and PS4 are in the auto position and theload has been satisfied the unit will go into one time pumpdown and will remain off until MicroTechsenses a call for cooling and starts the unit. Under no circumstance use the compressors forpumpdown with the liquid line valves closed.

CAUTION

The unit must not be cycled off by using the evaporator pump or the disconnect switch.

It is important that the water flow to the unit is not interrupted before the compressors pumpdown toavoid freeze-up in the evaporator.

If all power is turned off to the unit the compressor heaters will become inoperable. Once power isresumed to the unit it is important that the compressor heaters are energized a minimum of 12 hoursbefore attempting to start the unit. Failure to do so could damage the compressors due to excessiveaccumulation of liquid in the compressor.

Start-up After Temporary Shutdown1. Insure that the compressor heaters have been energized for at least 12 hours prior to starting the

unit.

2. Start the chilled water pump.

3. With System switch S1 in the "on" position, move pumpdown switches PS1, PS2, PS3 and PS4 tothe "auto" position.

4. Observe the unit operation until the system has stabilized.

WARNING

If shutdown occurs or will continue through periods below freezing ambient temperatures, protect thechiller vessel from freezing.

Extended (Seasonal) Shutdown1. Move the PS1, PS2, PS3 and PS4 switches to the manual pumpdown position.

2. After the compressors have pumped down, turn off the chilled water pump.

3. Turn off all power to the unit and to the chilled water pump.

4. Move the emergency stop switch S1 to the "off" position.

5. Close the compressor suction and discharge valves as well as the liquid line shutoff valves.

6. Tag all opened disconnect switches to warn against start-up before opening the compressorsuction and discharge valves and liquid line shutoff valves.

7. If glycol is not used in the system, drain all water from the unit evaporator and chilled waterpiping if the unit is to be shutdown during winter. Do not leave the vessels or piping open to theatmosphere over the shutdown period.

8. Leave power applied to the evaporator heating cable if a separate disconnect is used.

74 IOMM ALS-3

Start-up After Extended (Seasonal) Shutdown1. With all electrical disconnects open, check all screw or lug type electrical connections to be sure

they are tight for good electrical contact.

2. Check the voltage of the unit power supply and see that it is within the ±10% tolerance that isallowed. Voltage unbalance between phases must be within ±3%.

3. See that all auxiliary control equipment is operative and that an adequate cooling load is availablefor start-up.

4. Check all compressor valve connections for tightness to avoid refrigerant loss. Always replacevalve seal caps.

5. Make sure system switch S1 is in the "Stop" position and pumpdown switches PS1, (PS2, PS3and PS4) are set to "Pumpdown and Stop," throw the main power and control disconnectswitches to "on." This will energize crankcase heaters. Wait a minimum of 12 hours beforestarting up unit. Turn compressor circuit breakers to "off" position until ready to start unit.

6. Open the compressor suction and discharge valves as well as the liquid line shutoff valves.

7. Vent the air from the evaporator water side as well as from the system piping. Open all water flowvalves and start the chilled water pump. Check all piping for leaks.

IOMM ALS-3 75

System Maintenance

GeneralOn initial start-up and periodically during operation, it will be necessary to perform certain routineservice checks. Among these are checking the liquid line sightglasses and taking condensing andsection pressure readings. Through the MicroTech keypad, check to see that the unit has normalsuperheat and subcooling readings. A recommended maintenance schedule is located at the end ofthis section.

A Periodic Maintenance Log is located at the end of this manual. It is suggested that the report becompleted on a weekly basis. The log will serve as a useful tool for a service technician in the eventservice is required.

Compressor MaintenanceSince the compressor is semi-hermetic no yearly compressor maintenance is normally required.However, vibration is an excellent check for proper mechanical operation. Compressor vibration is anindicator of the requirement for maintenance and contributes to a decrease in unit performance andefficiency. It is recommended that the compressor be checked with a vibration analyzer at or shortlyafter start-up and again on an annual basis. When performing the test the load should be maintainedas closely as possible to the load of the original test. The initial vibration analyzer test provides abenchmark of the compressor and when performed routinely can give a warning of impendingproblems.

LubricationNo routine lubrication is required on ALS units. The fan motor bearings are permanently lubricated.No further lubrication is required. Excessive fan motor bearing noise is an indication of a potentialbearing failure.

Compressor oil must be Planetelf ACD68AW. McQuay Part Number 735030439 in a 5 galloncontainer, 735030438 in 1 gallon size. This is synthetic polyolester oil with anti-wear additives and ishighly hygroscopic. Care must be taken to minimize exposure of the oil to air when charging oil intothe system.

An oil filter is located in the oil return line from the oil separator to the compressor. This filter shouldbe replaced if the pressure drop exceeds 25 psi as measured at Schrader fittings up and down streamfrom the filter.

Electrical TerminalsWARNING

Electric shock hazard. Turn off all power before continuing with following service.

Periodically check electrical terminals for tightness and tighten as required.

CondensersThe condensers are air-cooled and constructed of 3/8" (9.5mm) O.D. internally finned copper tubesbonded in a staggered pattern into louvered aluminum fins. No maintenance is ordinarily requiredexcept the routine removal of dirt and debris from the outside surface of the fins. McQuayrecommends the use of foaming coil cleaners available at most air conditioning supply outlets. Usecaution when applying such cleaners as they may contain potentially harmful chemicals. Care shouldbe taken not to damage the fins during cleaning.

76 IOMM ALS-3

If the service technician has reason to believe that the refrigerant circuit contains noncondensables,purging may be required strictly following Clean Air Act regulations governing refrigerant dischargeto the atmosphere. The purge Schrader valve is located on the vertical coil header on both sides ofthe unit at the control box end of the coil. Access panels are located at the end of the condenser coildirectly behind the control panel. Purge with the unit off, after shutdown of 15 minutes or longer, toallow air to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shutunit off and repeat the procedure. Follow accepted environmentally sound practices when removingrefrigerant from the unit.

Refrigerant SightglassThe refrigerant sightglasses should be observed periodically. (A weekly observation should beadequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system toinsure proper feed through the expansion valve. Bubbling refrigerant in the liquid line sightglass,during stable run conditions, indicates that the system may be short of refrigerant charge. Refrigerantgas flashing in the sightglass could also indicate an excessive pressure drop in the liquid line,possibly due to a clogged filter-drier or a restriction elsewhere in the liquid line (see Table 48 formaximum allowable pressure drops). If subcooling is low add charge to clear the sightglass. Ifsubcooling is normal (10°-15°F) and flashing is visible in the sightglass check the pressure dropacross the filter-drier. Subcooling should be checked at full load with 70°F (21.1°C) outdoor airtemperature and all fans running.

An element inside the sightglass indicates the moisture condition corresponding to a given elementcolor. If the sightglass does not indicate a dry condition after about 12 hours of operation, the circuitshould be pumped down and the filter-drier changed.

Lead-LagA feature on all McQuay ALS air-cooled chillers is a system for alternating the sequence in which thecompressors start to balance the number of starts and run hours. Lead-Lag of the refrigerant circuitsis accomplished automatically through the MicroTech Controller. When in the auto mode the circuitwith the fewest number of starts will be started first. If all circuits are operating and a stage down inthe number of operating compressors is required, the circuit with the most operating hours will cycleoff first. The operator may override the MicroTech controller, and manually select the lead circuit ascircuit #1, #2, #3 or circuit #4.

IOMM ALS-3 77

Preventative Maintenance SchedulePREVENTATIVE MAINTENANCE SCHEDULE

OPERATION WEEKLYMONTHLY

(Note 1)ANNUAL(Note 2)

General Complete unit log and review (Note 3) X Visually inspect unit for loose or damaged components X Inspect thermal insulation for integrity X Clean and paint as required X

Electrical Check terminals for tightness, tighten as necessary X Clean control panel interior X Visually inspect components for signs of overheating X Verify compressor heater operation X Megger compressor motor every five years

Refrigeration Leak test X Check sight glasses for clear flow X Check filter-drier pressure drop (see manual for spec) X Perform compressor vibration test X

Condenser (air-cooled) Clean condenser coils (Note 4) X Check fan blades for tightness on shaft (Note 5) X Check fans for loose rivets and cracks X Check coil fins for damage X

Notes:

1. Monthly operations include all weekly operations.

2. Annual (or spring start-up) operations includes all weekly and monthly operations.

3. Log readings may be taken daily for a higher level of unit observation.

4. Coil cleaning may be required more frequently in areas with a high level of airborne particles.

5. Be sure fan motors are electrically locked out.

78 IOMM ALS-3

Service

CAUTION

1. Service on this equipment is to be performed by qualified refrigeration personnel familiar withequipment operation, maintenance, correct servicing procedures, and the safety hazards inherentin this work. Causes for repeated tripping of equipment protection controls must be investigatedand corrected.

2. Disconnect all power before doing any service inside the unit.

3. Anyone servicing this equipment shall comply with the requirements set forth by the EPA inregards to refrigerant reclamation and venting.

Compressor SolenoidsThe ALS unit screw compressors are equipped with 3 solenoids to control compressor unloading.The solenoids are controlled by MicroTech outputs. See unit wiring diagrams. The solenoids areenergized at various compressor load conditions as indicated in the table below.

Table 47, Compressor UnloadingCOMPRESSOR UNLOADING SOLENOID STATUSTOP BOTTOM FRONT BOTTOM REAR

COMPRESSORLOADING %

SOLENOID SOLENOID SOLENOID100% Energized Off Energized75% Energized Energized Off50% Off Of f Energized25% Off Energized Off

Location of the solenoids is as follows:

The top solenoid is on top of the compressor near the discharge end.

The bottom solenoids are on the lower side of the compressor on the opposite side from the terminalbox. The bottom front solenoid is the one closest to the discharge end of the compressor. Thebottom rear solenoid is the one closest to the motor end of the compressor.

If the compressor is not loading properly check the solenoids to see if they are energized per theabove chart. A complete check will include a check of the MicroTech output, the wiring to thesolenoid and the solenoid coil itself.

Filter-DriersA replacement of the filter-drier is recommended any time excessive pressure drop is read across thefilter-drier and/or when bubbles occur in the sightglass with normal subcooling. The maximumrecommended pressure drop across the filter-drier is as follows:

Table 48, Filter-Drier Pressure DropPERCENT CIRCUIT MAXIMUM RECOMMENDED PRESSURE

LOADING (%) DROP ACROSS FILTER DRIER PSIG (KPA)

100% 7 (48.3)

75% 5 (34.5)

50% 3 (20.7)

25% 3 (20.7)

The filter-drier should also be changed if the moisture indicating liquid line sightglass indicates excessmoisture in the system.

IOMM ALS-3 79

During the first few months of operation the filter-drier replacement may be necessary if the pressuredrop across the filter-drier exceeds the values listed in the paragraph above. Any residual particlesfrom the condenser tubing, compressor and miscellaneous components are swept by the refrigerantinto the liquid line and are caught by the filter-drier.

The following is the procedure for changing the filter-drier core:

This procedure is slightly different from a typical reciprocating compressor unit due to the use of aliquid injection feature on the ALS screw compressor unit. Anytime the compressor contactor isclosed, liquid from the liquid line is injected into the screw for cooling and sealing the rotor. Thisliquid injection also occurs during normal pumpdown and limits how low a pumpdown pressure can beachieved.

The standard unit pumpdown is set to stop pumpdown when 34 psig (235 kPa) suction pressure isreached. To fully pump down a circuit beyond 34 psig (235kPa) for service purposes a "FullPumpdown" service mode can be activated using the keypad. Go to the "Alarm Spts" Menu on theMicroTech keypad, step through the menu items until "FullPumpDwn" is displayed. Change thesetting from "No" to "Yes".

The next time either circuit is pumped down, the pumpdown will continue until the evaporatorpressure reaches 2 psig (14 kPa) or 60 seconds have elapsed, whichever occurs first. Uponcompleting the pumpdown, the "FullPumpDwn" set point is automatically changed back to "No".

The procedure to perform a full service pumpdown for changing the filter-drier core is as follows:

1. Perform a normal pumpdown to 34 psig (235 kPa) by moving the pumpdown switch to the"Pumpdown" position. This step will pump down the evaporator with compressor liquid injectionstill active.

2. Under the "Alarm Spts", change the "FullPumpDwn" set point from "No" to "Yes".

3. The circuit status should be "Off:PumpDwnSw". Move the circuit pumpdown switch from"Pumpdown and Stop" to "Auto". Also clear the anticycle timers through the MicroTechkeypad.

4. The compressor should pump down the circuit until the evaporator pressure reaches 2 psig (14kPa) or 60 seconds has elapsed, whichever occurs first.

5. Upon completing the full pumpdown per step 4, the "FullPumpDwn" set point is automaticallychanged back to "No" which reverts back to standard 34 psig (235 kPa) stop pumpdown pressure.

6. If the pumpdown does not go to 2 psig (14 kPa) on the first attempt, one more attempt can bemade by repeating steps 3, 4 and 5 above. Do not repeat "FullPumpDwn" more than once toavoid excessive screw temperature rise under this abnormal condition.

7. The circuit is now in the deepest pumpdown which can equipment protection be achieved by theuse of the compressor. Close the liquid line shutoff valve upstream of the filter-drier, on thecircuit to be serviced plus the suction shutoff valve and the liquid/vapor shutoff valve. Anyremaining refrigerant must be removed from the circuit by the use of a refrigerant recovery unit.

8. Loosen the cover bolts, remove the cap and remove the filter.

9. Evacuate and open valves.

Remove and replace the filter-drier(s). If the refrigerant circuit is opened for more than 10 minutesevacuate the lines through the liquid line manual shutoff valve(s) to remove noncondensables thatmay have entered during filter replacement. A leak check is recommended before returning the unit tooperation.

80 IOMM ALS-3

Liquid Line Solenoid ValveThe liquid line solenoid valves that shut off refrigerant flow in the event of a power failure does notnormally require any maintenance. (On a sudden power failure the electronic expansion valveremains open at the position it was at when the power failure occurred. During normal operationthe EEV closes for automatic pumpdown and the liquid line solenoid valve closes only when thecompressor stops.) The solenoids may, however, require replacement of the solenoid coil or of theentire valve assembly.

The solenoid coil can be checked to see that the stem is magnetized when energized by touching ascrewdriver to the top of the stem. If there is no magnetization either the coil is bad or there is nopower to the coil.

The solenoid coil may be removed from the valve body without opening the refrigerant piping afterfirst moving pumpdown switches PS1, PS2, and PS3 to the "manual pumpdown" position and openingthe S1 switch. For personal safety shut off and lock out the unit power.

The coil can then be removed from the valve body by simply removing a nut or snap-ring located atthe top of the coil. The coil can then be slipped off its mounting stud for replacement. Be sure toreplace the coil on its mounting stud before returning pumpdown switches PS1, PS2 and PS3 to the"auto pumpdown" position. Failure to do so will lead to solenoid coil failure.

To replace the entire solenoid valve follow the steps involved when changing a filter-drier.

Electronic Expansion ValveThe electronic expansion valve is located adjacent to the compressor. The refrigerant is piped to firstpass through the electronic expansion valve, then through the motor housing cooling the motorbefore going into the evaporator. Refer to the Figure 33, ALS Piping Schematic.

The expansion valve meters the amount of refrigerant entering the evaporator to match the coolingload. It does this by maintaining a constant superheat. (Superheat is the difference between theactual refrigerant temperature of the vapor as it leaves the evaporator and the saturation temperaturecorresponding to the evaporator pressure.) All ALS chillers are factory set between 8°F (4.5°C) and12°F (6.6°C) superheat at 75% to 100% load and between 6°F (3.3°C) and 10°F (5.6°C) below 75% load.The superheat is controlled by the microprocessor and is not adjustable.

The expansion valve, like the solenoid valve, should not normally require maintenance, but if itrequires replacement, the unit must be pumped down by following the steps involved when changinga filter-drier.

If the problem can be traced to the electric motor only, it can be unscrewed from the valve bodywithout removing the valve but only after pumping the unit down. Disassemble valve at the brass hexnut. Do not disassemble valve at the aluminum housing.

IOMM ALS-3 81

Figure 34, Electronic Expansion Valve

Electronic Expansion Valve OperationThere are three colored indicator LEDs (green, red, yellow) located in the control panel on theelectronic expansion valve (EXV) board. When the control panel is first powered the microprocessorwill automatically step the valve to the fully closed (shut) position and the indicator lights on the EXVwill blink in sequence. The valve can also be heard closing as it goes through the steps. The valvewill take approximately 14 seconds to go from a full open position to a full closed position.

The position of the valve can be viewed at any time by using the MicroTech keypad through thecircuit pressure menus. There are a total of 760 steps between closed and full open.

A feature of the electronic expansion valve is a maximum operating pressure setting (MOP). Thissetting limits the load on the compressor during start-up periods where high return evaporator watertemperatures may be present. The valve will limit the maximum suction pressure at start-up toapproximately 85 psig (586 kPa). The valve will close to a point necessary to maintain the 85 psig (586kPa). During this time the superheat will rise above 12°F (6.6°C) and not drop below 12°F (6.6°C) untilthe suction pressure drops below 85 psig (586 kPa). The valve will maintain evaporator pressure closeto 85 psig (586 kPa) until the evaporator water temperature decreases to approximately 55°F to 60°F(12.7°C to 15.6°C).

When the circuit starts the valve opens as soon as the evaporator pressure decreases to 40 psig (275kPa). At the end of the cooling cycle the valve closes causing the system to pump down. The valvecloses at the rate of approximately 55 steps per second, or from full open to full closed inapproximately 14 seconds. The valve closing during pumpdown will occur in approximately 20-30seconds after the pumpdown switch is moved to the "Pumpdown and Stop" position.

EvaporatorThe evaporator is the direct expansion, shell-and-tube type with refrigerant flowing through the tubesand water flowing through the shell over the tubes. The tubes are internally finned to provide

82 IOMM ALS-3

extended surface as well as turbulent flow of refrigeration through the tubes. Normally no servicework is required on the evaporator.

Charging RefrigerantALS air-cooled screw chillers are shipped factory charged with a full operating charge of refrigerantbut there may be times that a unit must be recharged at the job site. Follow these recommendationswhen field charging. Refer to the unit operating charge found in the Physical Data Tables, Table 14through Table 19.

Unit charging can be done at any steady load condition (preferably at 75 to 100% load) and at anyoutdoor temperature (preferably higher than 70°F (21.1°C). Unit must be allowed to run 5 minutes orlonger so that the condenser fan staging is stabilized at normal operating discharge pressure. For bestresults charge with two or more condenser fans operating on each refrigerant circuit.

The ALS units have a condenser coil design with approximately 15% of the coil tubes located in asubcooler section of the coil to achieve liquid cooling to within 5°F (3°C) of the outdoor airtemperature when all condenser fans are operating. This is equal to about 15°F-20°F (8.3°C-11.1°C)subcooling below the saturated condensing temperature when the pressure is read at the liquid valvebetween the condenser coil and the liquid line filter drier. Once the subcooler is filled, extra charge willnot lower the liquid temperature and does not help system capacity or efficiency. However, a littleextra (10-15 lbs) will make the system less sensitive.

Note: As the unit changes load or fans cycle on and off, the subcooling will vary but should recoverwithin several minutes and should never be below 6°F (3.3°C) subcooling at any steady statecondition. Subcooling will vary somewhat with evaporator leaving water temperature and suctionsuperheat. As the evaporator superheat decreases the subcooling will drop slightly.

One of the following two scenarios will be experienced with an undercharged unit:1. If the unit is slightly undercharged the unit will show bubbles in the liquid line sightglass.

Recharge the unit as described in the charging procedure below.

2. If the unit is moderately undercharged it will normally trip on freeze protection. Recharge the unitas described in the charging procedure below.

Procedure to charge a moderately undercharged ALS unit:1. If a unit is low on refrigerant you must first determine the cause before attempting to recharge the

unit. Locate and repair any refrigerant leak. Evidence of oil is a good indicator of leakage,however oil may not be visible at all leaks. Liquid leak detector fluids work well to show bubblesat medium size leaks but electronic leak detectors may be needed to locate small leaks.

2. Add the charge to the system through the suction shutoff valve or through the Schrader fittingon the tube entering the evaporator between the compressor and the evaporator head.

3. The charge can be added at any load condition between 25-100% load per circuit but at least twofans should be operating per refrigerant circuit if possible. The suction superheat should be inthe 6°F-12°F (3.3°C-6.6°C) range.

4. Add sufficient charge to clear the liquid line sightglass and until all flashing stops in thesightglass. Add an extra 15-20 lbs. of reserve to fill the subcooler if the compressor is operatingat 50-100% load.

5. Check the unit subcooling value by reading the liquid line pressure and temperature at the liquidline near the king valve. The subcooling values should be between 6°F-20°F (6.6°C-11.1°C). Thesubcooling values will be lowest at 75-100% load, approximately 10°F-15°F (5.5°C-8.2°C) andhighest at 50% load, approximately 28°F-32°F (15.4°C-17.6°C at 25% load).

6. With outdoor temperatures above 60°F (15.6°C) all condenser fans should be operating and theliquid line temperature should be within 5°F-10°F (2.8°C-5.6°C) of the outdoor air temperature. At25-50% load the liquid line temperature should be within 5°F (2.8°C) of outdoor air temperaturewith all fans on. At 75-100% load the liquid line temperature should be within 10°F (5.6°C) ofoutdoor air temperature with all fans on.

IOMM ALS-3 83

7. Overcharging of refrigerant will raise the compressor discharge pressure due to excessivecovering of the condenser tubes with refrigerant.

Charging OilThe oil separator is equipped with two sightglasses that are used to determine the oil level.Each sight glass has a ball float retained in it thatfloats on the oil. A ball located in the top of theglass signifies that the oil level is somewhereabove the top of the glass. A ball located at thebottom signifies that the oil level is somewherebelow the bottom of the glass.

1. If the bottom sight glass ball is not at the top,oil should be added. This condition can alsocause NoOil NoRun alarms.

2. Pump oil into the system per instruction #2above. It is preferable to add oil at 100%circuit operation.

3. Add oil during operation until the top sightglass ball begins to float.

Notes:

• At part load operation oil will not be visible in the top sight glass, i.e. the ball will be at thebottom of the glass.

• Under any operating condition, the bottom glass should be full of oil, i.e. the ball should beat the top of the glass.

• The only acceptable oil is Planetelf ACD68AW.

BallFloat

BallFloat

UpperSight Glass

LowerSight Glass

OilSeparator

84 IOMM ALS-3

In-Warranty Return Material Procedure

In the U.S. and CanadaCompressor: In the event of a failure contact the nearest McQuayService office for assistance.

Components Other Than Compressors: Material may be returned only with permission fromauthorized factory service personnel of McQuay International in Staunton, Virginia. A "returngoods" tag will be sent and is to be shipped with the returned material. Enter the requiredinformation on the tag in order to expedite handling at our factories.

The return of the part does not constitute an order for replacement. Therefore, a purchase order mustbe entered through your nearest McQuay representative. The order should include part name, partnumber, model number and serial number of the unit involved.

Following McQuay's inspection of the returned part, and if it is determined that the failure is due tofaulty material or workmanship, and it is within the warranty period, credit will be issued against thecustomer’s purchase order.

All parts shall be returned to the designated McQuay factory with transportation charges prepaid.

IOMM ALS-3 85

Standard Controls

Thermistor sensorsNote: Refer to the current version of OM ALSMICRO-x for a more complete description of thecontrols application, settings, adjustments, and checkout procedures.

All sensors are premounted and connected to the MicroTech field wiring strip with shielded cable. Adescription of each sensor is listed here.

Evaporator leaving water temperature - This sensor is located on the evaporator water outletconnection and is used for capacity control of the chiller and low water temperature freeze protection.

Evaporator entering water temperature - This sensor is located on the evaporator water inletconnection and is used for monitoring purposes and return water temperature control.

Evaporator pressure transducer circuit #1 - This sensor is located on the suction side of compressor#1 and is used to determine saturated suction refrigerant pressure and temperature. It also provideslow pressure freeze protection for circuit #1.

Evaporator pressure transducer circuit #2 - This sensor is located on the section side of compressor#2 and is used to determine saturated suction refrigerant pressure and temperature. It also provideslow pressure freeze protection for circuit #2.



Condenser pressure transducer circuit #1 - the sensor is located on the discharge of compressor #1and is used to read saturated refrigerant pressure and temperature. The transducer will unload thecompressor should a rise in head pressure occur which is outside the MicroTech set point limits. Thesignal is also used in the calculation of circuit #1 subcooling.

Condenser pressure transducer circuit #2 - The sensor is located on the discharge of compressor #2and is used to read saturated refrigerant pressure and temperature. The transducer will unload thecompressor should a rise in head pressure occur which is outside the MicroTech set point limits. Thesignal is also used in the calculation of circuit #2 subcooling.

Condenser pressure transducer circuit #3 - the sensor is located on the discharge of compressor #3and is used to read saturated refrigerant pressure and temperature. The transducer will unload thecompressor should a rise in head pressure occur which is outside the MicroTech set point limits. Thesignal is also used in the calculation of circuit #3 subcooling.

Condenser pressure transducer circuit #4 - The sensor is located on the discharge of compressor #4and is used to read saturated refrigerant pressure and temperature. The transducer will unload thecompressor should a rise in head pressure occur which is outside the MicroTech set point limits. Thesignal is also used in the calculation of circuit #4 subcooling.

Outside air - This sensor is located on the back of the control box on compressor #1 side. It measuresthe outside air temperature, is used to determine if low ambient start logic is necessary and can be thereference for low ambient temperature lockout.

Suction temperature circuit #1 - The sensor is located in a well brazed to circuit #1 suction line. Thepurpose of the sensor is to measure refrigerant temperature to control and maintain proper superheat.

86 IOMM ALS-3




Discharge line temperature circuit #1 - The sensor is located in a well brazed to circuit #1 dischargeline. It measures the refrigerant temperature and is used to calculate discharge superheat.




Demand limit - This requires a field connection of a 4-20 milliamp DC signal from a buildingautomation system. It will determine the maximum number of cooling stages which may be energized.

Evaporator water temperature reset - This requires a 4-20 milliamp DC signal from a buildingautomation system or temperature transmitter to reset the leaving chilled water set point.

Percent total unit amps - (optional) this is located in the power side of the control panel. Anadjustable voltage resistor and a signal converter board sends a DC signal proportional to the totalcompressor motor current to the microprocessor.

High condenser pressure controlMicroTech is also supplied with high pressure transducers on each refrigerant circuit. The mainpurpose of the high pressure transducer is to maintain proper head pressure control. Anotherpurpose is to convey a signal to the MicroTech control to unload the compressor in the event of anexcessive rise in discharge pressure to within 20 psi (138 kPa) of the condenser pressure controlsetpoint of 380 psig (2620 kPa). Also, a MicroTech control setting will not allow additional circuitloading at approximately 40 psi (276 kPa) below the high pressure switch trip setting. The highpressure alarm is in response to the signal sent by the pressure transducer. The high pressuretransducer can be checked by elevating discharge pressure (see Mechanical High Pressure EquipmentProtection Control) and observing the MicroTech display (or a pressure gage), and unit operation asthe pressures pass the rising high pressure values noted. After the test reset the High CondenserPressure alarm set point to 380 psig (2620 kPa).

Mechanical high pressure equipment protection controlThe high pressure equipment protection control is a single pole pressure activated switch that openson a pressure rise. When the switch opens, the control circuit is de-energized dropping power to thecompressor and fan motor contactors. The switch is factory made to open at 400 psig (2760 kPa) (+10psig) and reclose at 300 psig (2070 kPa). Although the high pressure switch will close again at 300psig (2070 kPa), the control circuit will remain locked out and it must be reset through MicroTech.

The control is mounted on the compressor attached to a fitting ahead of the discharge shut off valve.

IOMM ALS-3 87

Remove wire 133 from terminal 20 of the MicroTech controller. This will disable all but one fan.Observe the cut out point of the control through the MicroTech keypad display, or by means of aservice gauge on the back seat port on the discharge service valve. Important: Closely monitor theHigh Pressure Control and stay within reach of the emergency stop switch. Do not let the pressureexceed 420 psig (2900 kPa) during the test. If the condenser pressure reaches 420 psig (2900 kPa)open the emergency stop switch. The MicroTech keypad display may read slightly lower than aservice gauge. Upon completion of the test reset the High Pressure Control back to 380 psig (2620kPa).

To check the control on circuit #2 repeat the same procedure after removing wire 233 from terminal 30.

Compressor motor protectionThe compressors are supplied with two types of motor protection. Solid state electronic overloadsmounted in the control box sense motor current to within 2% of the operating amps. The MUST TRIPamps are equal to 140% of unit nameplate compressor RLA. The MUST HOLD amps are equal to125% of unit nameplate RLA. A trip of these overloads can result from the unit operating outside ofnormal conditions. Repeat overload trips under normal operation may indicate wiring or compressormotor problems. The overloads are manual reset and must be reset at the overload as well as throughMicroTech.

The compressors also have a solid state Guardister circuit that provides motor over temperatureprotection. The Guardister circuit has automatic reset but must also be reset through MicroTech.

FanTrol head pressure controlFanTrol is a method of head pressure control that automatically cycles the condenser fans in responseto condenser pressure. This maintains head pressure and allows the unit to run at all ambient airtemperatures within the control design parameters.

All ALS units have independent circuits with the fans being controlled independently by thecondensing pressure of each circuit. If one circuit is off all fans on that circuit will also be off. Theuse of multiple fans enables the unit to have excellent head pressure control at low outside ambienttemperatures by cycling the fans to maintain the compressor discharge pressure within the desiredoperating band.

At outdoor temperatures above approximately 65°F (18.3°C) all of the fans for a circuit will beoperating to achieve the most efficient unit operation. At any compressor load condition of 50% orabove the unit has the highest overall efficiency with all fans operating. When the compressorunloads below 50% the last fan stage is cut off because the fan energy saved is more than theincrease of compressor power at this light loading. Below approximately 65°F (18.3°C) outdoortemperature the fans are cycled off as needed on each refrigerant circuit by the MicroTech control tomaintain the compressor discharge pressure in the optimum range for best unit operation and highestoverall efficiency.

MicroTech controls fans in response to the system discharge pressure. The use of MicroTech tostage on the fans as needed allows more precise control and prevents undesirable cycling of fans.

One fan always operates with the compressor and other fans are activated one at a time as needed.The control uses 6 stages of fan control with four outputs to activate up to six additional fans percircuit. MicroTech logic sequences fan contactors to stage one fan at a time. On units with six orseven fans per circuit, a single fan is cut off when two fans are started to achieve adding oneoperating fan. See Table 49.

88 IOMM ALS-3

Table 49, Fan StagingALS 141C THRU ALS 150C (FANS PER CKT=5)

MicroTech fan stage 0 1 2 3 4Fan output relay on - 1 1,2 1,2,3 1,2,3,4Total fans operating 1 2 3 4 5

ALS 171C THRU ALS 186C (FANS PER CKT=6) (Note 1)MicroTech fan stage 0 1 2 3 4 5Fan output relay on - 1 1,2 1,2,3 1,2,4 1,2,3,4Total fans operating 1 2 3 4 5 6

ALS 190C THRU 218C (FANS PER CKT=7) (Note 2)MicroTech fan stage 0 1 2 3 4 5 6Fan output relay on - 1 1,2 1,3 1,2,3 1,3,4 1,2,3,4Total fans operating 1 2 3 4 5 6 7

ALS 220C THRU ALS 245C (FANS PER CKT=5)MicroTech fan stage 0 1 2 3 4Fan output relay on - 1 1,2 1,2,3 1,2,3,4Total fans operating 1 2 3 4 5

ALS 220C THRU ALS 245C (FANS PER CKT=6) (Note 3)MicroTech fan stage 0 1 2 3 4 5Fan output relay on - 1 1,2 1,2,3 1,2,4 1,2,3,4Total fans operating 1 2 3 4 5 6

ALS 260C THRU ALS 295C (FANS PER CKT=7)MicroTech fan stage 0 1 2 3 4 5Fan output relay on - 1 1,2 1,2,3 1,2,4 1,2,3,4Total fans operating 1 2 3 4 5 6

ALS 325C THRU ALS 365C (FANS PER CKT=5)MicroTech fan stage 0 1 2 3 4Fan output relay on - 1 1,2 1,2,3 1,2,3,4Total fans operating 1 2 3 4 5

ALS 375C THRU ALS 420C (FANS PER CKT=6)MicroTech fan stage 0 1 2 3 4 5Fan output relay on - 1 1,2 1,2,3 1,2,4 1,2,3,4Total fans operating 1 2 3 4 5 6

Notes:1. On ALS 171C thru 186C, two fans are controlled by fan output #4.2. On ALS 190C thru 218C, two fans each are controlled by fan outputs #3 and #4.3. On ALS 245C thru 245C Ckt #3 only and ALS 260 thru 295C two fans are controlled by fan output #4. Each output relay

controls one fan except output relay #4 that controls two fans.

MicroTech evaluates several factors to determine the number of fans to be operated. These include:

1. The compressor loading as percent of full load.2. The minimum lift pressure required at this load (The lift pressure equals the discharge pressure

minus the suction pressure.)3. The addition of a control pressure band to the minimum lift pressure to prevent fan cycling.4. A target discharge pressure is determined by adding the minimum lift pressure to the suction

pressure.At any operating condition the MicroTech controller will determine the minimum lift pressure and atarget discharge pressure, and will add or remove operating fans in sequence until the dischargepressure reaches the target value or falls within the control band of pressure set just above the targetpressure value.

Each fan added has a decreasing percentage effect so the control pressure band is smaller when morefans are on and largest with only one or two fans on.

Unit operation, with FanTrol, is satisfactory down to outdoor temperatures of 30°F (-1.1°C). Belowthis temperature the SpeedTrol option is required to regulate the speed of the first fan on the systemto adequately control the discharge pressure. SpeedTrol option allows unit operation to 0°F (-17.8°C)outdoor temperature assuming that no greater than 5 mph wind. If SpeedTrol is used in conjunctionwith wind baffles and hail guards, the unit can operate down to -10°F (-23°C).

For windy locations operating below 40°F (-1.1°C) outdoor air temperature, wind gusts must beprevented from blowing into the unit coils by either locating the unit in a protected area or by theaddition of field supplied wind barriers or by mounting optional factory supplied wind barriers.

IOMM ALS-3 89

FanTrol operation example:

Unit operating at 100% load on both circuits

Suction Pressure = 65 psig (448 kPa)

Minimum lift pressure at 100% load = 12- psig (828 kPa)

Minimum dis charge pressure = 65 + 120 psig = 185 psig (1276 kPa)

Discharge pressure control band = 35 psig (241 kPa)

Maximum discharge pressure = 185 + 35 = 220 psig (1517 kPa)

If the discharge pressure is between the minimum of 185 psig (1276 kPa) and maximum of 220 psig(1517 kPa) the fan stages in operation are correct and if the pressure falls outside this range theMicroTech controller will stage fans on or off to bring it within range.

CAUTION

SpeedTrol and FanTrol will provide reasonable operating refrigerant discharge pressures at theambient temperatures listed for them provided the coil is not affected by the existence of wind. Windbaffles must be utilized for low ambient operation below 40°F if the unit is subjected to winds greaterthan 5 mph.

Low ambient startLow ambient start is incorporated into the MicroTech logic. The MicroTech will measure thedifference between freezestat and evaporator pressure and determine the length of time thecompressor will be allowed to run (to build up evaporator pressure) before taking the compressor offline. The danger of allowing the compressor to run for to long before building up evaporator pressureis that the evaporator could freeze. The low ambient timer setting is determined by the pressureshown in Table 50. If the low ambient timer is greater than the maximum time allowed the MicroTechwill shut off the compressor and display an alarm.

Table 50, Pressure Difference vs. Time to Alarm

PRESSURE DIFFERENCE BETWEEN TIME

FREEZESTAT AND EVAPORATOR (SECONDS)

12 psig (84 kPa) 180

8 psig (56 kPa) 240

4 psig (28 kPa) 300

0 psig (0 kPa) 360

Phase/voltage monitorThe phase/voltage monitor is a device that provides protection against three-phase electrical motorloss due to power failure conditions, phase loss, and phase reversal. Whenever any of theseconditions occur, a contact opens to the MicroTech controller (PVR Input) which then de-energizes allinputs.

When proper power is restored, contacts close and MicroTech enables compressors for operation.

When three-phase power has been applied, the output relay should close and the "run light" shouldcome on. If the output relay does not close, perform the following tests.

1. Check the voltages between L1-L2, L1-L3 and L2-L3. These voltages should be approximatelyequal and within +10% of the rated three-phase line-to-line voltage.

2. If these voltages are extremely low or widely unbalanced check the power system to determine thecause of the problem.

90 IOMM ALS-3

3. If the voltages are within range, use a phase tester to verify that phases are in A, B, C sequencefor L1, L2 and L3. Correct rotation is required for compressor operation. If incorrect phasesequence is indicated, turn off the power and interchange any two of the supply power leads atthe disconnect switch.

This may be necessary as the phase/voltage monitor is sensitive to phase reversal. Turn on thepower. The output relay should now close after the appropriate delay.

Compressor short cycling protectionMicroTech contains logic to prevent rapid compressor restarting. Excessive compressor starts can behard on starting components and create excessive motor winding temperatures. The anti-cycle timersare set for a five-minute stop-to-start cycle and a 15-minute start-to-start cycle. Both are adjustablethrough MicroTech.

Optional ControlsSpeedTrol head pressure control (optional)The SpeedTrol system of head pressure control operates in conjunction with MicroTech’s standardhead pressure control by modulating the motor speed on fans 11, 21, 31, and 41 in response tocondensing temperature. By reducing the speed of the last fan as the condensing pressure falls, theunit can operate at lower ambient temperatures. Start-up with low ambient temperature is improvedbecause the SpeedTrol fans 11, 21,31, and 41 do not start until the condenser pressure builds up.

The SpeedTrol fan motor is a single phase, 208-230/460 volt, thermally protected motor speciallydesigned for variable speed application. The solid-state speed controls SC11, SC21, SC31, and SC41are accessible through the panel directly above the control box. Units with 575 volt power have atransformer mounted inside the condenser fan compartment to step the voltage down to 230 volts forthe SpeedTrol motor.

The SpeedTrol control starts to modulate the motor speed at less than 65°F (18.3°C) and maintains aminimum condensing pressure of 170 to 180 psig (1172 to 1241 kPa) at full circuit load. For part loadoperation the condensing pressure is allowed to fall below this level.

IOMM ALS-3 91

Controls, Settings and FunctionsTable 51, Controls

DESCRIPTION FUNCTION SYMBOL SETTING RESET LOCATION

Compressor Heaters To provide heat to drive off liquid refrigerant when

compressor is off.

HTR1,2,3,4 On, when compressor

is off .

N/A On the Compressor

Compressor

Solenoid - Top

In circuit 1,2,3 and 4 energizes to load 50% of

compressor capacity.

CS11,21,

31,41

N/A N/A On the Compressor

Compressor

Solenoid - Bottom

In circuit 1,2,3 and 4 energizes to unload 25% of


CS12,22,

32,42


Compressor

Solenoid - Bottom

In circuit 1,2,3 and 4 energizes to load 25% of


CS13,23,

33,43


Evaporator Heater Coiled around the evaporator to prevent freezing

the water inside.

HTR5 38oF (3.3oC) N/A On the Cooler

Electronic Expansion

Valve Board

To provide power and step control to the EXV

stepper motors commanded by the MCB250.

EXV (Bd) N/A N/A Control Box

Electronic Expansion

Valve

To provide efficient unit refrigerant flow and control

superheat.

EXV In Controller Code N/A On the Compressor

main liquid line

Solid State Starter

Thermister Card

To provide motor temperature protection at about

220oF (104oC).

K2 Fault None,

Inherent in design

Auto Starter Box

Mechanical High

High Pressure Switch

For UL, ETL, etc…safety code to prevent high

pressure above the relief valve.

MHPR1,2,3,4 Refer to

OM ALSMICRO

Auto Control Box

MicroTech Unit

Controller

To control unit and all safeties. Refer to OM

ALSMICRO.

MCB250 N/A Refer to

OM

ALSMICR

Control Box

Solid State Starter K2 Protects the compressor motor from over heating

due to high amps.

K2 Fault Solid State Starter

Parameter #1

Manual Starter Box

Phase Voltage Monitor to prevent reverse rotation of the motor and

protect it from under/over voltage.

PVM1,2,3,4 N/A Auto Control Box

Reduced Inrush

Time Delay

To provide 1 sec delay for reduced inrush. TD5,6,7,8 Set 4Vdc

for full load amps

N/A Control Box

Signal Converter To convert AC current signal volts to DC volts. SIG.Con

V (SC)

0-75 psig

(0-517 kPa)

N/A Control Box

Solenoid Valve

Liquid Line

To provide a positive shut off of liquid refrigerant

when power is lost.

SVLIQ N/A N/A Liquid Line

Solenoid Valve

Interstage Injection

To allow liquid injection into the screw for cooling SVINT N/A N/A On compressor

oil Injection

SpeedTrol Head

Pressure Control

To provide more uniform head pressure control. SC11,21,

31,41

N/A N/A Above Control Box

Surge Capacitor To protect from high voltage spikes and surges. C1,2,3,4 N/A N/A Control Box

Power Side

Oil Separator Heaters Provide heat to maintain viscosity at low

temperatures

HTR 6-13 On when compressor

is off

N/A Oil Separator

Notes: Symbol column shows application components for four-compressor units. For two and three compressor units, not all components are applicable

92 IOMM ALS-3

Troubleshooting ChartTable 52, Troubleshooting

PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS

Compressor will notrun.

1. Main power switch open.2. Unit S1 system switch open.3. Circuit switch PS1, PS2, PS3, PS4 in pumpdown position.4. Evap flow switch not closed.5. Circuit breakers open.6. Fuse blown or circuit breakers tripped.

7. Unit phase voltage monitor not satisfied.8. Compressor overload tripped.

9. Defective compressor contactor or contactor coil.10. System shut down by protection devices.

11. No cooling required.12. Motor electrical trouble.13. Loose wiring.

1. Close switch.2. Check unit status on MicroTech display. Close switch.3. Check circuit status on MicroTech display. Close switch.4. Check unit status on MicroTech display. Close switch.5. Close circuit breakers.6. Check electrical circuits and motor windings for shorts or grounds.

Investigate for possible overloading. Check for loose or corrodedconnections. Reset breakers or replace fuses after fault iscorrected.

7. Check unit power wiring to unit for correct phasing. Check voltage.8. Overloads are manual reset. Reset overload at button on overload.

Clear alarm on MicroTech.9. Check wiring. Repair or replace contactor.10. Determine type and cause of shutdown and correct problem before

attempting to restart.11. Check control settings. Wait until unit calls for cooling.12. See 6,7,8 above.13. Check circuits for voltage at required points. Tighten all power wiring

terminals

Compressor Noisyor Vibrating

1. Compr. Internal problem.2. Liquid injection not adequate.

1. Contact McQuayService.2. Check to assure liquid line sightglass is full during steady operation.

CompressorOverload RelayTripped or CircuitBreaker Trip orFuses Blown

1. Low voltage during high load condition.2. Loose power wiring.3. Power line fault causing unbalanced voltage.4. Defective or grounded wiring in the motor.5. High discharge pressure.

1. Check supply voltage for excessive voltage drop.2. Check and tighten all connections.3. Check supply voltage.4. Check motor and replace if defective.5. See corrective steps for high discharge pressure.

Compressor WillNot Load or Unload

1. Defective capacity control solenoids.2. Unloader mechanism defective.

1. Check solenoids for proper operation. See capacity control section.2. Replace.

Compressor LiquidInjection ProtectionTrip

1. Liquid injection solenoid did not open at start.2. Inadequate liquid to liquid injection at start due to a clogged

filter drier or low charge.3. Inadequate liquid to liquid injection during run.

1. Check and replace liquid injection solenoid.2. Check liquid injection line sight glass. If flashing check filter drier

and unit charge.3. Check liquid injection line sightglass. If flashing check filter-drier and

unit charge. Discharge pressure too low. Protect condenser coil fromwind.

High DischargePressure

1. Discharge shutoff valve partially closed.2. Noncondensables in the system.3. Fans not running.4. Fan control out of adjustment.

5. System overcharged with refrigerant.

6. Dirty condenser coil.7. Air recirculation from outlet into unit coils.8. Air restriction into unit.

1. Open shutoff valve.2. Purge the noncondensables from the condenser coil after shutdown.3. Check fan fuses and electrical circuits.4. Check that unit setup in MicroTech matches the unit model number.

Check MicroTech condenser pressure sensor for proper operation.5. Check for excessive subcooling above 30°F (-1.1°C). Remove the

excess charge.6. Clean the condenser coil.7. Remove the cause of recirculation.8. Remove obstructions near unit.

Low DischargePressure

1. Wind effect a low ambient temperature.2. Condenser fan control not correct.

3. Low section pressure.4. Compressor operating unloaded.

1. Protect unit against excessive wind into vertical coils.2. Check that unit setup in MicroTech matches the unit model number.

Check SpeedTrol fan on units with SpeedTrol option.3. See corrective steps for low suction pressure.4. See corrective steps for failure to load.

Low SuctionPressure

1. Inadequate refrigerant charge quantity.

2. Inadequate liquid to liquid injection at start. Clogged liquidline filter-drier.

3. Expansion valve malfunctioning.

4. Insufficient water flow to evaporator.5. Water temperature leaving evaporator is too low.6. Evaporator tubes fouled.7. Evaporator head ring gasket slippage.

8. Glycol in chilled water system

1. Check liquid line sightglass. Check unit for leaks. Repair andrecharge to clear sightglass.

2. Check pressure drop across filter-drier. Replace cores.

3. Check expansion valve superheat and valve opening position.Replace valve only if certain valve is not working.

4. Check water pressure drop across the evaporator and adjust gpm.5. Adjust water temperature to higher value.6. Inspect by removing water piping. Clean chemically.7. Low suction pressure and low superheat both present may indicate

an internal problem. Consult factory.8. Check glycol concentration

High SuctionPressure

1. Excessive load - high water temperature.2. Compressor unloaders not loading compressor.3. Superheat is too low.

1. Reduce load or add additional equipment.2. See corrective steps below for failure of compressor to load.3. Check superheat on MicroTech display. Check suction line sensor

installation and sensor.

IOMM ALS-3 93

Periodic Maintenance Log

94 IOMM ALS-3

IOMM ALS-3 95

Post Office Box 2510, Staunton, Virginia 24402 USA • (800) 432-1342 • www.mcquay.com

Documents

Air-Cooled Screw Compressor Chiller · 2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit unless extra clearance is provided