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TABLE OF CONTENTSPage
SAFETY CONSIDERATIONS ...................................................2INTRODUCTION ........................................................................2UNIT IDENTIFICATION ...........................................................2PRODUCT OFFERING ..............................................................4FAN MOTOR SPEED TAPS .....................................................4FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4ACIRCUIT BOARD FUNCTION AND TROUBLESHOOTING— CES013003-00 and -01 PCB...............................................2-7• Printed Circuit Board Component Layout and Description.......2• Unit Functions ............................................................................2• Troubleshooting PCB ..................................................................5CIRCUIT BOARD FUNCTION AND TROUBLESHOOTING
— HK61GA001 and HK61GA003 PCB.........................8-19• Printed Circuit Board Component Layout and Description.......8• PCB Component Functions.........................................................9• Troubleshooting PCB ................................................................11ELECTRIC HEATER FUNCTION
AND TROUBLESHOOTING ..............................................19• Description of Electric Heater Components.............................19• Troubleshooting KFA, KFB, KFC, and KFD Series
Electric Heaters.......................................................................20FAN COIL DESCRIPTION
AND TROUBLESHOOTING — FK4B .......................20-27• Integrated Controls and Motor (ICM2) ....................................20• PCB Layout and Description ....................................................20• Sequence of Operation ..............................................................21• Easy Select Configuration Taps................................................22• Troubleshooting PCB ................................................................24• Troubleshooting ICM2 ..............................................................26• Condensed Version of Troubleshooting FK4B Motorand Controls ...............................................................................26
• Accessories ................................................................................27FAN COIL DESCRIPTION
AND TROUBLESHOOTING — FK4C, FV4A ...........28-34• Integrated Controls and Motor (ICM2) ....................................28• PCB Layout and Description ....................................................28• Sequence of Operation ..............................................................28• Easy Select Configuration Taps................................................30• Troubleshooting PCB ................................................................32• Troubleshooting ICM2 ..............................................................34• Condensed Version of Troubleshooting
FK4C, FV4A Motor and Controls .........................................34• Accessories ................................................................................34THERMOSTATIC EXPANSION VALVES (TXV) ..............35• Problems Affecting TXV ..........................................................36PISTON BODY CLEANING OR REPLACEMENT ............36LIQUID TUBE STRAINER .....................................................36FA, FB, FC, FK COIL/CONDENSATE PAN
REMOVAL AND REPLACEMENT ..................................36• A-Coil Units ..............................................................................36• Slope Coil Units ........................................................................37FX, FV COIL/CONDENSATE PAN REMOVAL
AND REPLACEMENT ........................................................38
CARE AND MAINTENANCE .................................................39• Filter Assembly .........................................................................39• Cooling Coil, Drain Pan, and Condensate Drain .....................39• Blower Motor and Wheel .........................................................39FF1A/FF1B/FF1C SERVICE AND
TROUBLESHOOTING ..................................................40-42• Fan Motor ..................................................................................40• Electric Heater Service..............................................................40• Cleaning or Replacing Refrigerant Flow-Control Device .......40• Liquid Tube Strainer .................................................................40• Sequence of Operation ..............................................................40• Care and Maintenance...............................................................40
FD3A SERVICE AND TROUBLESHOOTING ...............44-45• Fan Motor ..................................................................................44• Electric Heater Service..............................................................44• Cleaning or Replacing Refrigerant Flow-Control Device .......44• Liquid Tube Strainer .................................................................44• Care and Maintenance...............................................................45FG3A SERVICE AND TROUBLESHOOTING ...............45-46• Service .......................................................................................45• Maintenance...............................................................................46FA4A, FB4A, FC4B, FX4A SMART HEAT CIRCUIT
BOARD FUNCTION AND TROUBLESHOOTING ..46-50• PCB Component Layout, Description, and Function...............46• Unit Functions ...........................................................................46• Smart Heat Operation................................................................47• Electrical Operating Sequences and Troubleshooting..............48PURON® (R-410A) QUICK REFERENCE GUIDE .............50
Fig. 1—Typical Fan CoilA98023
Service Manual
RESIDENTIAL FAN COIL UNITS
Cancels: SM03-4 SM03-56-99
—1—
This symbol→ indicates a change since the last issue.
SAFETY CONSIDERATIONSImproper installation, adjustment, alteration, service, maintenance,or use can cause explosion, fire, electrical shock, or otherconditions which may cause personal injury or property damage.Consult a qualified installer, service agency, or your distributor orbranch for information or assistance. The qualified installer oragency must use factory-authorized kits or accessories whenmodifying this product. Refer to the individual installation instruc-tions packaged with the kits or accessories for detailed informa-tion.Follow all safety codes. Wear safety glasses and work gloves. Usequenching cloth for brazing operations. Have fire extinguisheravailable. Read these instructions thoroughly and follow allwarnings or cautions attached to the unit. Consult local buildingcodes and National Electrical Code (NEC) for special installationrequirements.It is important to recognize safety information. This is thesafety-alert symbol . When you see this symbol on the unit or ininstructions and manuals, be alert to the potential for personalinjury.Understand the signal words DANGER, WARNING, and CAU-TION. These words are used with the safety-alert symbol. DAN-GER identifies the most serious hazards whichwill result in severepersonal injury or death. WARNING signifies hazards whichcould result in personal injury or death. CAUTION is used toidentify unsafe practices whichwould result in minor personalinjury or product and property damage.
CAUTION: Puron (R-410A) systems operate at higherpressures than R-22 systems. Do not use R-22 serviceequipment or components on R-410A equipment. Ensureservice equipment is rated for R-410A.
INTRODUCTIONThe "F" series fan coil units are designed for flexibility in a varietyof applications, meeting upflow, horizontal, or downflow require-ments. Units are available in 1-1/2 through 5 ton nominal coolingcapacities. Factory-authorized, field-installed electric heater pack-ages are available in 3 through 30 kilowatts.
WARNING: Before installing or servicing fan coil,always turn off all power to unit. There may be more than1 disconnect switch. Turn off accessory heater power ifapplicable. Electrical shock can cause personal injury ordeath.
UNIT IDENTIFICATIONThe 16 position numbering chart allows identification of allavailable fan coil units. (See Fig. 2.)
FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4ACIRCUIT BOARD
FUNCTION AND TROUBLESHOOTINGCES0130003-00 and -01 PCBThis section of the service manual describes the CESO130003-00and -01 PCB by examining the functional operation of the PCBcomponents.
I. PRINTED CIRCUIT BOARD (PCB) COMPONENTLAYOUT AND DESCRIPTION
Layout of the actual PCB is depicted in Fig. 3A.
1. The low-voltage stripped leads are used to connect the 24-vside of transformer to indoor thermostat and outdoorsection.
2. A 5-amp fuse is used to protect the low-voltage transformersecondary.
3. The fan relay is controlled by thermostat and turns fan onand off.
4. A plug is used as the connection for PCB power and electricheaters. Note the pin numbers on plug.
5. A time-delay relay circuit keeps fan motor running forapproximately 90 sec after G is de-energized. The time-delay can be defeated by cutting jumper JW1.
II. UNIT FUNCTIONS
A. Transformer
1. Proper Wiring of Transformer Primary or High Side
Yellow wire from Molex plug is wired to C terminal ontransformer and black wire from PCB relay (normally-open) terminal is wired to 208v or 230v terminal ontransformer. Units are factory wired at 230v terminal.
2. Proper Wiring of Transformer Secondary or 24-v Side
Red wire of transformer is wired to T terminal on PCB andbrown wire of transformer is wired to C terminal on PCB.
NOTE: T terminal on PCB is used to protect transformer. Tterminal is connected through the fuse to R terminal on PCB.
B. Indoor Fan
1. Wiring (See Fig. 3B for FF1D typical wiring diagram.)
Indoor fan motor yellow lead is wired to C terminal ontransformer. The red, blue, or black speed lead is wired toSPT terminal on fan relay part of PCB. Units are factorywired on medium speed (blue lead connected).
NOTE: Unused fan speed leads must be capped or taped off toprevent direct short to cabinet surface.
2. Functional Control
a. Thermostat and Relay Control
When thermostat calls for the fan in cooling, heat pump,heating, or fan-only mode, a 24-vac signal is sent torelay. This causes the relay to close its normally-opencontacts, turning on fan. When thermostat no longer callsfor the fan, the signal sent to relay is turned off and relayopens causing fan to turn off after a 90-sec fan-off delay.
b. Sequencer/Electric Heat Relay Interlock
The fan will also operate whenever there is a call forelectric heat, even if fan relay is not energized. Thishappens because fan is interlocked with first stage ofelectric heat through the normally-closed contact of fanrelay.
NOTE: The fan interlock is only connected to first stage electricheat W2. W3 and E do not contain an interlock with fan. Seeoutdoor thermostat Installation Instructions when electric heatstaging is desired.
C. Electric Heat
NOTE: Models FF1A/FF1B/FF1C use sequencers for electricheat. Model FF1D uses DC rectified relays for electric heat.(See Fig. 3C.)
When thermostat calls for electric heat, a 24-vac signal is sent tosequencer/heat relay through W2, causing first stage to turn on.W3 and E also receive signal if wired in with W2. The signal sentto W2 causes first stage to turn on. If W3 and E are not wired toW2, the sequencers/heat relays can be controlled individually tostage additional electric heat. The sequence control is described inthe following section:
—2—
Fig
.2—
Fan
Coi
l16-
Pos
ition
Num
berin
gS
yste
mA
9811
4
2nd
Pos
ition
—F
an C
oil
A -
RN
CB
- S
tand
ard
C -
Del
uxe
D -
Fur
red
in, C
ased
E -
Fur
red
in, U
ncas
edF
- T
hrou
gh th
e W
all
G -
Com
mer
cial
H -
Sta
ndar
d E
lect
ric F
urna
ceJ
- S
tand
ard
Hot
Wat
erK
- IC
M M
otor
, Hig
h E
ffici
ency
V -
ICM
Mot
or, P
uron
R-4
10A
X -
Sta
ndar
d, P
uron
R-4
10A
Un
it S
pec
ific
s
1 -
Upf
low
2 -
Dow
nflo
w3
- H
oriz
onta
l4
- M
ultip
oise
5 -
Upf
low
/Dow
nflo
w
Air
flo
w
018
(11 ⁄
2 T
on)
024
(2 T
on)
001
(Mul
ti T
ons)
002
(Mul
ti T
ons)
Etc
.Co
olin
g S
ize
10th
, 11t
h, 1
2th
Pos
ition
s—F
an C
oil
005
010
Etc
.
Hea
tin
g S
ize
(KW
)
6th
Pos
ition
—F
an C
oil
A -
Sta
ndar
dB
- M
odul
arF
- S
ingl
e P
iece
Co
il T
ype
5th
Pos
ition
—F
an C
oil
A -
115
-1-6
0N
- 2
08/2
30-1
-60
S -
230
-1-5
0
Ele
ctri
cal
F -
Fan
Coi
l
Typ
e o
f U
nit
A -
Orig
inal
B -
Sec
ond
Ser
ies
Maj
or
Ser
ies
A -
Orig
inal
Min
or
Ser
ies
A -
Sta
ndar
d U
nit
Var
iati
on
s
A -
Com
mon
Uni
t
Var
iati
on
s
12
34
56
7 8
910
11
1213
1415
16
—3—
TABLE 1—PRODUCT OFFERING
MODEL UNIT SIZE DESCRIPTION CABINETFA4ANF 018-060 Multipoise Single PieceFB4ANB 042-070 Multipoise ModularFB4ANF 018-060 Multipoise Single Piece
FB4ASB 042-060 Multipoise50 Hz Modular
FB4ASF 018-060 Multipoise50 Hz Single Piece
FC4BNB 042-070 Multipoise ModularFC4BNF 024-060 Multipoise Single PieceFD3ANA 018-030 Horizontal Single Piece
FF1A/FF1B/FF1C/FF1D 018-030 Vertical Single PieceFG3ANA 024, 036, 048, 060 Horizontal/Small Commercial Single PieceFH4ANB 003, 004 Multipoise ModularFH4ANF 001-004 Multipoise Single PieceFK4CNB 006 Multipoise ModularFK4CNF 001-005 Multipoise Single PieceFX4ANF 030-048 Multipoise Single PieceFX4ANB 060 Multipoise ModularFV4ANF 002, 003, 005 Multipoise Single PieceFV4ANB 006 Multipose Modular
NOTE: Multipoise units are approved for upflow, downflow, and horizontal left and right applications.
TABLE 2—PSC FAN MOTOR SPEED TAPS
MODEL UNITSIZENUMBER OF
SPEEDSHIGH
SPEEDMEDIUMSPEED
LOWSPEED COMMON
FA4A 018-036 2 Black — Blue YellowFA4A 042-060 3 Black Blue Red YellowFB4A 018-070 3 Black Blue Red YellowFC4B 024-070 3 Black Blue Red YellowFD3A 018-030 2 Black — Red Yellow
FF1A/FF1B/FF1C/FF1D 018-030 2 Black — Red Violet**FG3A 024, 036, 048, 060 1* — — — —FH4A 001-004 3 Black Blue Red YellowFX4A 030-060 3 Black Blue Red Yellow
*Belt drive.→**Yellow on FF1D
Fig. 3A—Fan Coil Printed-Circuit BoardA97020
LOWVOLTAGEFUSE
FAN RELAY
FUSE
PCB BLOCK WIRING
TIMEDELAY
NO
G R T C
NC
SPT
®
®
1005
-83-
161A
CP
C-E
94
V-0
1005
-161
LR40061
CE
SO
1300
03-0
1
HS
CI
5 A
MP
TR
GC
C
T
G
R
SP
T
K1
U1
R7R9R10
C8
C7
R2R3C3R6
R11
C4
C6
C5R8
R5R4
Q1
C1C2
F1
JW1
R1Z1
D2
D1
NO
NC
FA
N
RE
LAY
—4—
1. W2
When thermostat sends a signal to W2, a 24-vac signal isapplied across sequencer/relay number 1, causing it toclose. When sequencer/relay number 1 closes, first stage ofelectric heat is energized. In straight electric heat, fan is alsoenergized through the normally-closed contacts of fan relay.In cooling, heat pump, or manual fan mode, fan will alreadybe running since fan relay would have been energized.When thermostat stops calling for electric heat, the 24-vacsignal to sequencer/relay number 1 turns off and sequenceropens after a delay of 60 to 90 sec. Heaters equipped withrelays will be de-energized immediately. Whensequencer/relay opens, first stage of heat turns off alongwith fan, providing thermostat is not calling for the fan.
2. W3
When a signal is sent to W3, a 24-vac signal tosequencer/relay number 2 causes it to close, with secondstage of electric heat turning on. The 24-vac signal appliedto sequencer/relay number 1 causes fan to operate. Timingis such that sequencer/relay number 1 will turn on beforesequencer/relay number 2. When signal to W3 is turned off,sequencer/relay number 2 opens. If W2 is also satisfied,first stage of electric heat and fan will also turn off,providing thermostat is not calling for the fan.
3. E
When thermostat sends a signal to E, a 24-vac signal is sentto sequencer/relay number 3. The 24-vac signal applied tosequencer/relay number 3 turns on third stage of electricheat. The 24-vac signal applied to sequencer/relay number1 turns on first stage of electric heat and fan. Whenthermostat stops calling for electric heat, the signal tosequencers/relays 1, 2, and 3 are turned off, andsequencers/relays open. This causes electric heat to turn offwith fan providing thermostat is not calling for the fan.
NOTE: Electric heaters are factory wired with all stages tiedtogether. If independent staging is desired, consult outdoor ther-mostat installation instructions, or corporate thermostat instruc-tions.
III. TROUBLESHOOTING THE PRINTED-CIRCUITBOARD
Use wiring schematics shown in Fig. 4 and 5 as a guide introubleshooting PCB unless otherwise noted.
A. If Fan Will Not Turn On from Thermostat:
IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:
1. Check plug/receptacle connection. This supplies powerfrom heaters to PCB Fan Relay. Be sure plug is connectedproperly.
Fig. 3B—FF1D Typical Wiring DiagramA98229
SEE NOTE #7
F1
NONCSPT
OUTDOORUNIT
G
PCB BLK
C
INDOOR THERMOSTAT
BARRIER
CT
RFR
NOTES:
SEE RATING PLATE FOR VOLTS & HERTZ
DISCONNECT PER NEC
FIELD POWER WIRINGCOOLING CONTROLS
ELECTRIC HEAT
230V208V
BRN
REDTRAN
COM
GRN/YELGND
YEL
LO
HI
COM
RED
YELBLK FM
BRN BRN
CAP
RELAY 122 VDC COIL
R E C
SCHEMATIC DIAGRAM
COMPONENT ARRANGEMENT
CAUTION:
ATTENTION:NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND
NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150 V A LA TERRE
COM
208 V230 V
TRANRED
24 V
BRN
GND
NCNO
SPTFR
TC
1RG
PCB
F
L2 L1DISC
60A 60A
RED-LOW
BLK-HI
GRN/YEL-GND
FM BRNBRN
YEL-COM
FAN MOTOR THERMALLY PROTECTED
CAPGND
SEE NOTE #5
LEGEND
RED
ORNVIO
GND
2
HTR2 BLK8
LS26
HTR1 BLK 4LS1
RELAY 1YEL BLK
SEE NOTE #1
BLK
SYSTEM TRANSFORMER: 40.0VAFAN COIL/HEATER: 8.4VA
REMAINING VA AVAILABLE: 31.6VA
REC0 1
28 64
RELAY 1
CAP CAPACITORCOM COMMON
F FUSEFM FAN MOTOR
FIELD POWER WIRINGFR PCB FAN RELAY
EQUIPMENT GROUNDGND
SPT FAN SPEED TAP LOCATION
HTR HEATERLS LIMIT SWITCH
MARKED TERMINALPLUG AND RECEPTACLE
PCB PRINTED CIRCUIT BOARDREC RECTIFIER
TRAN TRANSFORMERUNMARKED TERMINAL
R W G
324494-101 REV. A
1. Use copper wire (75¡c min) only between disconnect switch and unit.2. To be wired in accordance with nec and local codes.3. If any of the original wire, as supplied, must be replaced, use the same or
equivalent type wire.4. Replace low voltage fuse with no greater than 5 AMP fuse.5. (2) Speed Motor uses HI (BLK) and LOW (RED).6. Smaller heaters will have fewer components.7. Connect R to R, G to G, etc., see outdoor instructions for details.8. Cooling controls wiring not used with electric heaters.
HTR HTR
LS LS
DISC DISCONNECT
YEL
YEL
BLUBLK
BRNRED
GRY
GRY
ORN
YEL BLK
DIS
C
DIS
CBLU
BLK
DIS
C
YEL
DIS
C
VIO
BLK
SEE
NO
TE #
8
SEE
NO
TE #
8
YEL
L1
SEE NOTE #6
L1 L2 L2
MINIMUM MOTOR SPEED SELECTIONFAN COIL SIZE
MOTOR SPEED ONE HTRMOTOR SPEED TWO HTR
LOLO LO
LO LOLO
018 024 030
ROTATION
This compartment must be closed except when servicing.
—5—
2. Check sequencer/relay number 1 and plug wiring. Yellowwire should be connected to pin number 9 of plug and tolimit switch. Black wire should be connected to pin number7 of plug and to sequencer/relay number 1.
3. Check field power leads L1 and L2. If these are notreceiving power, system cannot function.
IF TRANSFORMER HAS HIGH VOLTAGE APPLIED TO IT:
1. Check low-voltage transformer leads R (red) and C(brown). Be sure they are wired to correct locations.
2. Check output voltage of transformer secondary side R (red)and C (brown). Be sure transformer output is between 18and 30 vac. If transformer output is incorrect and trans-former is receiving correct input voltage (208v or 230v),then transformer needs to be replaced with recommendedtransformer. If no problem exists with transformer second-ary, proceed to items 3 and 4.
3. Check low-voltage fuse shown in Fig. 3A. If fuse is blown,replace it with an identical 5-amp fuse. The transformercannot supply power to board with fuse blown or loose. Iffuse blows when unit has power applied to it, the systemmost likely has 1 of the following problems:
a. Check all 24-v wiring for an electrical short.
b. The maximum load on transformer is 40 VA. If load ontransformer is excessive, the low-voltage 5-amp fusewill blow to protect transformer. If load exceeds VArating of transformer, a larger VA rated transformerneeds to be installed. Check sequencers/relays for exces-sive current draw.
c. Check wiring of heaters. If a heater is miswired, fusemay blow. If a heater is miswired, correct miswiring bycomparing it to heater wiring label.
4. Check connections on primary side of transformer. If theyare not connected properly, the transformer secondary
cannot supply the 24-v signal to energize fan relay. Iftransformer is receiving correct primary voltage but is notputting out correct secondary voltage, transformer needs tobe replaced.
B. If Electric Heat Stages Will Not Turn On But Fan WillTurn On:
IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:
1. Check plug connection between heaters and board. Thissupplies power to transformer and fan. Be sure plug isconnected properly.
2. Check sequencer/relay number 1 and plug wiring. Yellowwire should be connected to pin number 9 of plug and tolimit switch. Black wire should be connected to pin number7 of plug and to sequencer/relay number 1.
3. Check incoming high-voltage power leads. If these are notreceiving power, system cannot function.
IF TRANSFORMER HAS HIGH VOLTAGE APPLIED TO IT:
1. Check low-voltage transformer leads R (red) and C(brown). Make sure they are wired to correct location. Theunit will not function without proper connections.
2. Check output voltage of transformer secondary side R (red)and C (brown). If transformer output is low (less than 18vac), refer to items 3 and 4 of previous "If Transformer HasHigh Voltage Applied To It" section.
IF TRACES ARE OVERHEATED ON BACK OF PCB:
Usually whenever a trace is blown on PCB, it means either therehas been a high-voltage short or high voltage has been applied tolow-voltage circuit. This can be prevented by making sure PCB iswired correctly before PCB has power applied to it.
C. If Transformer Fuse Keeps Blowing:
When low-voltage fuse blows, it means transformer would haveblown if fuse had not been in circuit to protect it. The fuse usuallyblows when there is a high current draw on transformer, high
Fig. 3C—Electric Heater Control BoxesA98184
3127
53T-
O-D
60T
X11
HH
19Z
A94
5
C97
25L1
45-5
5F
3127
53T-
O-D
60T
X11
HH
19Z
A94
5
C97
25L1
45-5
5F
SPT
FANRELAY
NO
NC
5 PULL TO OPEN
WARNING
ELECTRIC SHOCKHAZARD
DISCONNECTREMOTE POWERSUPPLY BEFOREOPENING PANEL.
322861-101 REV. A
PULL TO OPEN
WARNING
ELECTRIC SHOCKHAZARD
DISCONNECTREMOTE POWERSUPPLY BEFOREOPENING PANEL.
322861-101 REV. A
3127
53T-
O-D
60T
X11
HH
19Z
A94
5
C97
01L1
45-5
5F
3127
53T-
O-D
60T
X11
HH
19Z
A94
5
C97
01L1
45-5
5F
FF1D CONTROL BOX
FF1A/FF1B/FF1C CONTROL BOX
—6—
voltage applied to low-voltage circuit, or a direct secondary short.When there is a high current draw on transformer, it is most likelybecause transformer has been shorted or system is trying to drawmore VA than transformer rating allows. When fuse blows becauseof high voltage, the system has mixed high- and low-voltagesignals.
1. Check wiring of sequencers/relays as shown in Fig. 4 and 5.Be sure transformer is not shorting out because thermostatwires are miswired.
2. Check wiring of sequencers/relays as shown in Fig. 4 and 5.Be sure low-voltage and high-voltage wiring is correct.
3. Check VA draw on transformer. If VA draw is more thanVA rating of transformer, fuse will blow. If this is the case,replace transformer with one that has a higher VA ratingand meets system specifications.
D. If Fan Runs Continuously:
1. If PCB has no low-voltage power, check blue and black fanleads. These may be switched at sequencer/relay.
2. If PCB has low-voltage power, check fan relay to see if it isopening and closing. It may be stuck in the normally-closedposition due to debris in relay.
Fig. 4—Wiring Diagram of Sequencer HeaterA94346
1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED,
USE THE SAME OR EQUIVALENT TYPE WIRE.5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.6. 20KW HEATER USES ONE DOUBLE POLE LS ON MIDDLE TOP ELEMENT.7. 18, 24 AND 30KW HEATERS USE DOUBLE POLE LIMIT SWITCHES.8. LARGEST HEATERS ARE SHOWN, SMALLER HEATERS WILL HAVE FEWER ELEMENTS AND
COMPONENTS.9. 1 PHASE HEATERS ARE SHOWN WIRED FOR SINGLE SUPPLY CIRCUIT.10. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.11. (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR USES HI (BLK) AND LOW
(BLU OR RED).12. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUCTION FOR DETAILS.13. IF WIRE CRIMP IS REMOVED AN EMERGENCY HEAT RELAY IS REQUIRED.
(SEE OUTDOOR-THERMOSTAT INSTRUCTIONS)
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING CAUTION:
ATTENTION:
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING150V TO GROUNDBLOWER MOTOR
ROTATION
CAPCOMFFM
FRFUGNDHVTBHTR
CAPACITORCOMMONLOW VOLTAGE FUSEFAN MOTORFIELD POWER WIRINGPCB FAN RELAYLINE FUSEEQUIPMENT GROUNDHIGH VOLTAGE TERM BLOCKHEATER
LS
PCBSEQTRAN
RECPCB
LEGEND
321214-101 REV. C
30KW 1PH SCHEMATIC DIAGRAM
FIELD POWER WIRING DISCONNECT PER NEC
SEE RATING PLATEFOR VOLTS & HERTZ
GND
HTR6 BLK12
LS6
YEL
FU6BLK
FU5 11YEL BLK
L2L1
HTR5 BLK10
LS59
SEQ 3BLK
HTR4 BLK8YEL LS4
YEL
BLK7YEL
BLK
HTR3 BLK6
LS35
SEQ 2
BLK
HTR2 BLK4
YEL
LS2YEL BLK3
YEL
BLK
HTR1 BLK2
LS11
SEQ 1
BLK
LIMIT SWITCHMARKED TERMINALPLUG AND RECEPTACLEPRINTED CIRCUIT BOARDSEQUENCERTRANSFORMERUNMARKED TERMINALRECEPTACLECIRCUIT BREAKER
BLKBLU
YEL
YEL
SEE NOTE #1
NOTES:
799
11 711 3 2 6 1
23 1644
GRY
OUTDOORUNIT
WHT
GR
Y
G
RED
BRN EW3W2
W2C
BRN
INDOORTHERMOSTAT
RE
D
WH
T
VIO
BR
N
RECP
PLUG
F1
SPT G
PCB BLK
CT
RFR
BLU BLK
230V208VYEL
BRNYEL
YEL
YEL-COM
CA
P
BRN
FMBRN
GRN/YEL-GND
BLK-HI
BLU-MEDRED-LO
BRN
REDTRAN
CO
M
RED
GRAYVIOORN
BRN
BLU BLK
SEQ1SEQ3
SEQ2
CB/FU3
CB/FU1
CB/FU4
CB/FU2
HVTB
NO
NC
9 11 7 23 16 4208/240VAC 24VAC 24VAC
PLUG
23 16 49 11 7
L1 L2
FIELD POWER WIRING
FIELDPOWERWIRING
BLKYEL
HTR6 BLK12
LS6
YEL
FU6FU5 11
YEL
BLK
HTR5 BLK10
LS59
SEQ 3BLK
HTR4 BLK8
YEL LS4
YEL
7BLK
HTR3 BLK6
LS35
SEQ 2
BLK
HTR2 BLK4
YEL
LS2YEL3
BLK
HTR1 BLK2
LS11
SEQ 1
BLK
YEL
YEL
CB/FU3
CB/FU1
CB/FU4
CB/FU2
FIELD POWER WIRING DISCONNECT PER NECSEE RATING PLATE FOR VOLTS & HERTZ
GND
BLKL2L1
SEE NOTE #1
HVTB
L3
VIOORNSEQ1
9 11 7 23
RED
PLUG
BRNGRAY
BRN
SEQ3
SEQ2
16 4208/240VAC 24VAC 24VAC
30KW 3PH SCHEMATIC DIAGRAM
RESP
YEL
BLK
BLK
COOLING CONTROL ONLY
SEE NOTE #13R
BARRIER SEE NOTE #12
BLU
—7—
E. Transformer Failure:
1. Check 208-v and 230-v transformer connections. They maybe miswired.
CIRCUIT BOARD FUNCTION AND TROUBLESHOOTINGHK61GA001 and HK61GA003 Circuit BoardsThis section of the service manual describes the HK61GA001 andHK61GA003 printed-circuit boards (PCB) by examining thefunctional operation of the printed-circuit board’s components.I. PCB COMPONENT LAYOUT AND DESCRIPTION
Layout of the actual printed-circuit boards are depicted inFig. 6 and Fig. 7.
1. The low-voltage terminal board is used to connect theindoor thermostat to the low, 24-v side of the transformer,and to serve as a junction between the indoor thermostat andthe outdoor section.
2. Break off the tabs.a. W2-3 — Used to control (stage) the second stage of
electric heat. The first stage controlling electric heat andthe indoor fan are interlocked through diodes.
b. W2-E — Used to control (stage) the third stage ofelectric heat.
3. A fuse is used to protect the low-voltage transformer.4. AUX 1 and AUX 2 are connections for the latent capacity
control, delay off kit, 2-speed kit and air conditioningaccessories.
5. F1, F2, F3, and F4 are connections for the indoor fan.6. EAC1 and EAC2 are 240-v connections, which parallel fan
lead connections, for the electronic air cleaner.7. L1 and L2 are 240-v connections which parallel power
input.
→ Fig. 5—Wiring Diagram of Relay HeaterA99121E
COMPONENT ARRANGEMENT
HTR1 HTR3 HTR2
COM
208 V230 V
TRANRED
24 V
BRN
SYSTEM TRANSFORMER: 40.0VAFAN COIL/HEATER: 11.8VA
REMAINING VA AVAILABLE: 28.2VA
LEGEND
1.Use copper wire (75 ̊C min.) only between disconnect switch and unit.2.To be wired in accordance with N.E.C. and local codes.3. If any of the original wire, as supplied, must be replaced, use the same or
equivalent type wire.4.Replace low voltage fuse with no greater than 5 amp fuse.5.Use 60 amp class K fuses only, for replacement.6.(3) speed motor shown. Optional (2) speed motor uses HI (BLK) and LOW
(BLU or RED).7.Connect R to R, G to G, etc., see outdoor instruction for details.8.Smaller heaters will have fewer components.
SEE NOTE #6
GND
RED-LOWBLU-MEDBLK-HI
GRN/YEL-GND
FM BRNBRNYEL-COM
FAN MOTOR THERMALLY PROTECTED
CAPGND
324984-101 REV. A
FIELD POWER WIRING DISCONNECT PER NECSEE RATING PLATEFOR VOLTS & HERTZ
GND L4 L2L1 L3
HTR4 BLK 4YEL LS4
YEL
2 BLK
HTR3 BLK 8LS3 6RELAY 2
BLK
HTR2 BLK
4
YEL
LS2
YEL
2
YEL
BLK
HTR1 BLK
4
LS12
RELAY 1
BLK
YEL
HTR
4
FU4
FU2
L2
CB1
L4
CB2
FU1
FU3
L3
CB1
L1
CB2
LS1 LS2
INTERNAL PROTECTION MAY BE EITHER FUSES OR CIRCUIT BREAKERS
L4 L3CB1
60A 60A
L2 L1CB2
60A 60A
NOTES:
MINIMUM MOTOR SPEED SELECTIONFAN COIL SIZE
LO LOMOTOR SPEED AT 20 KW -- MED LO LO
018 024 030 036 042 048 060 070
-- LO
PLUG44
6 116
RECP
VIO
BLU
99
BARRIER
YEL
BRN
WG
GR
Y
OUTDOORUNIT
SEE NOTE #8
SEE NOTE #1
NCNO
SPTFR
TC
1RG
PCB
F
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING CAUTION:
ATTENTION:
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND
NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150 V A LA TERRE
BLOWER MOTORROTATION
SCHEMATIC DIAGRAM
F1
SPT GRY
BLU BLK
WHT
REDG
PCB BLKBRN
RC
INDOOR THERMOSTAT
RED
WH
T
BRNC
T
RFR
711 711 3 2
23
VIOORNBLU BLK
NCNO
LS 3& 4
230V208V
BRN
REDTRAN
COM
GRNYELGND
YEL
LOMED
HI
COM
REDBLU
YELBLK
FM
BRN BRN
CAP
BLK
R E C
RELAY 122 VDC COIL
TDR
HEATERLIMIT SWITCHMARKED TERMINALPLUG AND RECEPTACLEPRINTED CIRCUIT BOARDRECTIFIERTRANSFORMERUNMARKED TERMINALTIME DELAYRECTIFIER
CIRCUIT BREAKERCAPACITORCOMMONLOW VOLTAGE FUSEFAN MOTORFIELD POWER WIRINGPCB FAN RELAYLINE FUSEEQUIPMENT GROUNDFAN SPEED TAP LOCATION
REC
HTRLS
PCB
TRAN
CBCAPCOM
FFM
FRFU
GNDSPT
BLU
W2
RELAY 3
RELAY 2
RELAY 322 VDC COIL
R E C
RELAY 222 VDC COIL
T D R
BRN
BRN
GRY
RED
R1 R2
R3
FU3FU1
FU4FU2
L3L1
L4L2
RELAY 1
RELAY 2
REC
TDRRELAY 3
8
6
4
2
1 0
8
6
4
2
1 0
8
6
4
2
1 0TDR
—8—
8. T1, T2 and T3 are connections for the primary, high-voltageside of the transformer.
9. The fan relay is controlled by the thermostat and turns thefan on and off.
10. A plug is used as the connection for the PCB power andelectric heaters. Note the pin numbers on the plug.
11. Diodes provide DC power for the fan relay and the firststage of electric heat: W2, W3 or E.
II. PCB COMPONENT FUNCTIONS
A. Low-Voltage Terminal Board
The low-voltage terminal board connects the indoor thermostat tothe outdoor unit as shown in Fig. 8. The terminals are listed asfollows along with their functional control.
1. R is used to connect the secondary side of the transformer.The red wire provides low voltage (24v) to the PCB and thethermostat. R is fused on the HK61GA003 board.
Fig. 6—HK61GA001 Printed-Circuit BoardA97025
2FC-1
AUX1
AUX2
DUMMY
DUMMY
DUMMY
COMMON
COMMON
240 VAC 240 VAC
TRANSFORMERAC LINE
FANRELAY
24VDC
FANEAC2L2T3T2T1
EAC1L1
F4
F3
F2
F1
123
456
789
101112
C
HK61GA001A
W2-
3W
2-E
5 A
MP
F
US
E
MA
XFA
N
TD
B
LOW VOLTAGETERMINAL BOARD
2ND STAGE
3RD STAGE
NOT USED
FUSE(LOW VOLTAGE)
CONNECTIONSFOR VARIOUSACCESSORIES
FAN CONNECTIONS
ELECTRONIC AIRCLEANER CONNECTIONS
ELECTRIC HEATBREAKOFF TABSFOR STAGING
HK61GA001
PLUG
INTERLOCKDIODES
TRANSFORMERCONNECTIONS
—9—
2. C is used to connect the brown wire of the thermostat toprovide a return path to ground through the fuse whichprotects the transformer. C is fused on the HK61GA001board.
3. G is used to control the switching of the relay to turn the fanon through the normally open contact of the relay.
4. Y on the HK61GA001 is used as the junction for theoutdoor section’s Y connection which controls the compres-
sor contactor for heat pump and cooling modes. TheHK61GA003 board contains a 90-sec fan-off delay whichbegins timing when the Y is de-energized.
5. O is used as a junction for a heat pump reversing valvecircuit.
Fig. 7—HK61GA003 Printed-Circuit BoardA97026
36912
25811
14710
LOW VOLTAGETERMINAL BOARD
2ND STAGE
3RD STAGE
FUSE(LOW VOLTAGE)
CONNECTIONSFOR VARIOUSACCESSORIES
FAN CONNECTIONS
ELECTRIC HEATBREAKOFF TABSFOR STAGING
HK61GA003
PLUG
TRANSFORMERCONNECTIONS
ELECTRONIC AIRCLEANER CONNECTIONS
FAN INTERLOCKDIODES AND FANTIME DELAY OFF
CIRCUIT
AUX1
W3
L
W2
O
E
Y
G
R
C
AUX2
DUMMY
DUMMY
DUMMY
COMMON
COMMON
240 VAC 240 VACTRANSFORMER
AC LINE
FANRELAY
24VDC
FANEAC2L2T3T2T1
EAC1L1
F4
F3
F2
F1
HK61GA003
Y
R
W2-
3
5 A
MP
F
US
E
MA
X2F
D-1
W2-
E
—10—
6. W2 is used to turn on the first stage of electric heat whichis interlocked with the fan through the normally closed fanrelay. Unless the tabs are broken off, all stages of electricheat will turn on when W2 receives a signal from thethermostat.
7. W3 is used to turn on the second stage of electric heat. Notethe W2 and W3 tab must be broken off for individualstaging to take place. Energizing W3 will always turn on thefirst stage through the diodes even if the tabs are broken off.
8. E is used to turn on the third stage of electric heat. Note thatthe W3 and E tab must be broken for this individual staging.Energizing E will always turn on the first stage through thediodes even if the tab is broken off.
9. L is used as a junction to wire a diagnostic light (LED) onselected thermostats.
B. Transformer
The proper wiring of the transformer on the HK61GA001 board isillustrated in Fig. 8. Note that T1, T2, and T3 are wired to theprimary or high side of the transformer. The blue wire is connectedto T3 for 208-v applications. The red wire is connected to T3 for230-v applications. Units are factory wired at 230v. The T2terminal is a dummy.
C. Indoor Fan
1. Wiring--The fan connects to F1, F2, F3, and F4 as shown inFig. 8. Note that F2 and F3 are dummy terminals. Thedesired fan speed is connected to F4 and the common isconnected to F1. Units are factory wired at medium speed.
2. Functional Controla. Thermostat and Relay Control--When the thermostat
calls for the fan in cooling, heat pump, electric heat, orfan-only mode, a24-v dcsignal is sent to the relay. Thiscauses the relay to close its normally open contacts, thusturning on the fan. When the thermostat no longer callsfor the fan, the signal sent to the relay is turned off andthe relay opens causing the fan to turn off. TheHK61GA003 board contains a 90-sec fan-off delay whenY is de-energized.
b. Sequencer Interlock--The fan will also turn on wheneverthere is any call for electric heat, even if the fan relay isnot energized. This happens because the fan is inter-locked with the first stage of electric heat through thenormally closed contact of the fan relay.
D. Electric Heat
When the thermostat calls for electric heat, a 24-v signal is sent tothe PCB through W2, causing the first stage to turn on. W3 and Ealso receive the signal if the tabs are not broken off the PCB. Thesignal sent to W2 causes the first stage to turn on. If the tabs arebroken off the PCB, the sequencers can be controlled individuallyto stage the electric heat. The sequence control is described in thefollowing section:
1. W2--When the thermostat sends a signal to W2, a 24-v dcsignal is applied across sequencer number 1, causing it toclose. When sequencer number 1 closes, the first stage ofelectric heat energizes after a short delay. In straight electricheat, the fan is also energized through the normally closedcontacts of the fan relay. In cooling, heat pump, or manualfan mode, the fan will already be running since the fan relaywould have been energized. When the thermostat stopscalling for electric heat, the 24-v dc signal to sequencernumber 1 turns off and the sequencer opens after a delay of60 to 90 sec. When the sequencer opens, the first stage ofheat turns off along with the fan, providing that thethermostat is not calling for the fan. Note that the electricheat cannot be turned on without the fan being turned on atthe same time. This is a fan interlock system.
2. W3--When a signal is sent to W3, 2 control signals are sentout to the sequencers; a 24-v dc signal to sequencer number1 through the diode interlock, and a 24-v ac signal tosequencer number 2. The 24-v ac signal applied to sequencenumber 2 causes the sequencer to close, with the secondstage of electric heat turning on after a short delay.
The 24-v dc signal applied to sequencer number 1 causes the firststage of electric heat to turn on in the same manner as described inW2 above. Note that W3 is interlocked with the fan, sincesequencer number 1 is turned on whenever W3 has a signal sent toit. Timing is such that sequencer number 1 will turn on beforesequencer number 2. When the signal to W3 is turned off,sequencer number 2 opens after a short delay. If W2 is alsosatisfied, the first stage of electric heat and the fan will also turnoff, providing the thermostat is not calling for the fan to be on.E--When the thermostat sends a signal to E 2 signals are sent outto the sequencers. A 24-v ac signal is sent to sequencer number 3and a 24-v dc signal is sent to sequencer number 1. The 24-v acsignal applied to sequencer number 3 turns on the third stage ofelectric heat. The 24-v dc signal applied to sequencer 1 turns on thefirst stage of electric heat and the fan in the same manner as W3.Note that E is also interlocked with the fan.When the thermostat stops calling for electric heat, the signals tosequencers 1 and 3 are turned off and the sequencers open. Thiscauses the electric heat to turn off with the fan if the thermostat isnot calling for the fan.E. Accessories
1. EAC1 and EAC2 for Electronic Air Cleanersa. There are 240-v electronic air cleaner contacts provided
at EAC1 and EAC2. The electronic air cleaner isconnected in parallel with the fan so that it is onwhenever the fan is on. A 120-v installation is similar infunction but connected between EAC2 and neutral of230-v: 120-v transformer connected to EAC1 and EAC2.Refer to electronic air cleaner literature for furtherinformation.
2. AUX1 and AUX2 for 2-Speed Fan Relay Kita. Use to control fan speed operation, high speed for
cooling, heat pump, and fan-only modes. Low speed isused for electric heat. Fig. 9 shows proper connection for24-v dc 2-speed fan relay kit. Note that kit’s relay coil isin parallel with fan relay coil on PCB connected toAUX1 and AUX2. Make sure the normally closedcontact is connected to the lower speed.
b. The latent capacity control kit is used to control fanspeed operation when the relative humidity is above a setpoint on humidistat. Humidistat opens and 2-speed fanrelay remains in normally closed position with fan motorrunning at a lower speed for maximum humidity control.Fig. 10 shows proper connection for latent capacitycontrol kit. Note that it is connected in the same manneras 2-speed fan relay kit but with relay connected tohumidistat (orange wires).
c. Time delay-off relay kit is used to increase the efficiencyof the system by delaying the fan from turning off afterthe thermostat is satisfied on the HK61GA001 board.The HK61GA003 board has this feature as standard. Theproper wiring and mounting of the time delay-off relaykit is shown in Fig. 11.
d. Latent capacity control and time delay-off connectionsare shown in Fig. 12, for the HK61GA001 board only.
III. TROUBLESHOOTING THE PRINTED-CIRCUITBOARD
Use Fig. 13 wiring schematic as a guide in troubleshooting thePCB unless otherwise noted.
—11—
Fig. 8—10kw to 20kw CircuitsA97027
2FC-1
W3
L
W2
O
E
Y
G
R
C
AUX1
AUX2
DUMMY
DUMMY
DUMMY
COMMON
COMMON
240 VAC 240 VAC
TRANSFORMERAC LINE
RELAY
24VDC
FANEAC2L2T3T2T1
EAC1L1
F4
F3
F2
F1
123
456
789
101112
C
HK61GA001A
TOINDOOR
THERMOSTAT
W2-
3W
2-E
5 A
MP
F
US
E
MA
XFA
N
TD
B
YEL LS 5 HTR5 BLK BLK10 9
YELFU5 FU6
SEQ 3
LS 6 HTR6 BLK BLK12 11
YEL LS 5 HTR5 BLK BLK6 5
YELFU3 FU4
SEQ 2
LS 4 HTR4 BLK BLK8 7
YEL LS 1 HTR1 BLK BLK
BLU-MED
BLU-MED
RED-LO
RED-LO
BRN
BRNCAP
2 1
YELFU1 FU2
SEQ 1
LS 2 HTR2 BLK BLK4 3
SEQ1
GRAY
YEL
BLU
BLK
GRAY
BRNBRN
BLK
BLKCOMM
TRAN BRN (24V)
RED (24V)
BLU
YEL
VIO
ORG
REDSEQ2SEQ3
BLK-HI
BLK-HI
GRN/YEL-GND
YEL-COM
FM
BLU(208V) RED
(230V)
LOW VOLTAGETERMINAL BOARD
CONNECT E TO EC TO C ETC.
—12—
Fig
.9—
Tw
o-S
peed
Fan
Rel
ayK
itA
9702
8
W3
W2
EG
CC
B
2-05
868-
2A
TW
O S
PE
ED
FA
N
RE
LAY
WIR
ING
LOW
VO
LTA
GE
BO
AR
D
L
FR
CB
FA
N R
ELA
YC
IRC
UIT
BO
AR
D
MA
RK
ED
TE
RM
INA
LU
NM
AR
KE
D T
ER
MIN
AL
FIE
LD C
TR
L W
IRIN
GF
AC
TO
RY
PO
WE
R W
IRIN
GF
IELD
PO
WE
R W
IRIN
G
AU
X
1A
UX
2
F4
24 V
DC
OR
G
RE
D
FR
LOW
MT
R S
PD
HI M
TR
SP
DF
AN
CO
MM
ON
UN
US
ED
LE
AD
BLK
208/
240
VA
C
CO
M
NO
NC
F3
F2
L2
F1
OY
RTRA
NSFORM
ER ACLINE
T1T2
COMMON
COMMON
DUMMYT3L2
L1F1
F2
F3
F4
2SD-1
C
AUX1
AUX2 VA
C
EAC2
FANEAC
1
LO
YR
CG
EW
2W
3
AU
X 1
AU
X 2
OR
G
RE
D
BLK
YE
L
NO
TO
�H
IGH
ER
F
AN
SP
EE
D
LOW
-VO
LTA
GE
C
OIL
TE
RM
INA
LS
NC
TO
�LO
WE
R
FA
N S
PE
ED
DU
MM
Y T
ER
MIN
ALS
FO
R
UN
US
ED
FA
N M
OT
OR
S
PE
ED
-TA
P
LEA
DS
FA
N M
OT
OR
C
OM
MO
N L
EA
D
—13—
Fig
.10
—La
tent
Cap
acity
Con
trol
Kit
A97
029
VAC
W3
W2
EG
CC
B
2-05
868-
1A
LAT
EN
T C
AP
AC
ITY
C
ON
TR
OL
WIR
ING
LOW
VO
LTA
GE
BO
AR
D
L
FR
CB
FA
N R
ELA
YC
IRC
UIT
BO
AR
DH
ST
HU
MID
IST
AT
MA
RK
ED
TE
RM
INA
LU
NM
AR
KE
D T
ER
MIN
AL
FIE
LD C
TR
L W
IRIN
GF
AC
TO
RY
PO
WE
R W
IRIN
GF
IELD
PO
WE
R W
IRIN
G
AU
X
1A
UX
2
F4
24 V
DC
RE
D
FR
LOW
MT
R S
PD
HI M
TR
SP
DF
AN
CO
MM
ON
UN
US
ED
LE
AD
BLK
208/
240
VA
C
NO C
HS
T
OR
G
OR
G
CO
M
NO
NC
F3
F2
L2
F1
OY
R
TRANSF
ORMER AC
LINET1
T2COM
MON
COMMON
DUMMYT3L2
L1F1
F2
F3
F4
2SD-1
C
AUX1
AUX2
EAC2
FANEAC
1
LO
YR
CG
EW
2W
3
AU
X 1
AU
X 2
RE
D
BLK
YE
L
NO
TO
�H
IGH
ER
F
AN
SP
EE
DO
RA
NG
E W
IRE
S
TO
HU
MID
IST
AT
NC
TO
�LO
WE
R
FA
N S
PE
ED
FA
N M
OT
OR
C
OM
MO
N L
EA
D
—14—
Fig
.11
—T
ime
Del
ay-O
ffR
elay
Kit
A97
030
W3
W2
EG
CC
B
1
23
2-05
868-
3A
TIM
E D
ELA
Y
RE
LAY
WIR
ING
LOW
VO
LTA
GE
BO
AR
D
L
FR
CB
FA
N R
ELA
YC
IRC
UIT
BO
AR
DT
DR
TIM
E D
ELA
Y R
ELA
Y
MA
RK
ED
TE
RM
INA
LU
NM
AR
KE
D T
ER
MIN
AL
FIE
LD C
TR
L W
IRIN
GF
AC
TO
RY
PO
WE
R W
IRIN
GF
IELD
PO
WE
R W
IRIN
G
AU
X
1A
UX
2
F4
24 V
DC
TD
RY
EL
FA
N C
OM
MO
NU
NU
SE
D L
EA
DU
NU
SE
D L
EA
D
BLK
208/
240
VA
C
CO
M
NO
NC
F3
F2
L2
F1
OY
R
TRANSF
ORMER AC
LINET1
T2COM
MON
COMMON
DUMMYT3L2
L1F1
F2
F3
F4
2FC-1
HK61GA
001
G
C
C
AUX1
AUX2
EAC2
FANEAC
1
LO
YR
CG
EW
2W
3
TO
FA
N M
TR
S
PE
ED
TA
PV
IOB
RN
YE
L
YE
L
BLK
BR
N
VIO
FA
N
MO
TO
R
CO
MM
ON
LE
AD
FA
N
MO
TO
R
SP
EE
D-T
AP
LE
AD
—15—
Fig
.12
—La
tent
Cap
acity
Con
trol
and
Tim
eD
elay
-Off
Rel
ayK
itsA
9703
1
W3
W2
EG
CC
B
1
23
2-05
868-
4A
TIM
E D
ELA
Y R
ELA
Y
TW
O S
PE
ED
FA
N R
ELA
Y
(LA
TE
NT
CA
PA
CIT
Y)
LOW
VO
LTA
GE
BO
AR
D
L
FR
CB
FA
N R
ELA
YC
IRC
UIT
BO
AR
DH
ST
HU
MID
ST
AT
TD
RT
IME
DE
LAY
RE
LAY
MA
RK
ED
TE
RM
INA
LU
NM
AR
KE
D T
ER
MIN
AL
FIE
LD C
TR
L W
IRIN
GF
AC
TO
RY
PO
WE
R W
IRIN
GF
IELD
PO
WE
R W
IRIN
G
AU
X
1A
UX
2
F4
24 V
DC
TD
RF
R OR
G
OR
GR
ED
YE
L
FA
N C
OM
MO
NU
NU
SE
D L
EA
DLO
W M
TR
SP
DH
I MT
R S
PD
BLK
208/
240
VA
C
CO
M
NO
NC
F3
F2
L2
F1
OY
R
CO
M
NO
NC
TRANSF
ORMER AC
LINET1
T2COM
MON
COMMON
DUMMYT3L2
L1F1
F2
F3
F4
2SD-1
G
C
VAC
EAC2
FANEAC
1
LO
YR
CG
EW
2W
3
VIO
BR
N
YE
L
VIO
FA
N
MO
TO
R
CO
MM
ON
LE
AD
RE
DO
RG
BLK
BR
N
YE
L
AU
X 2
AU
X 1
OR
G
OR
G
BLU
LOW
-VO
LTA
GE
C
OIL
TE
RM
INA
LS
TO
HU
MID
IST
AT
(O
PT
ION
AL,
SH
OW
N
WIT
H D
AS
HE
D L
INE
S)
NO
TO
�H
IGH
ER
F
AN
SP
EE
D
NC
TO
�LO
WE
R
FA
N S
PE
ED
NO C
HS
T
—16—
Fig. 13—Wiring SchematicA97032
DUMMY
DUMMY
F4
F3
F2
F1
DUMMY
240 VAC 240 VAC COMMON
240 VDC
COMMON
T2
AC LINE
T1
123
W3
W2
E
L
O
Y
C
R
G
456
789
1011
PLUG
RELAY
12
T3L2 EAC2
AUX1
C 5 AMPFUSEMAX
AUX2
L1 EAC1
FAN
RL
GE
CO
YW
2
IND
OO
R T
HE
RM
OS
TA
T
YELYEL BLK
LS 3 HTR3 BLK BLK6 5
YELFU1 FU2FU3 FU4
SEQ 2
LS 4 HTR4 BLK BLK8 7
YEL LS 1 HTR1 BLK BLK2 1
YEL
SEQ 1
LS 2 HTR2 BLK BLK4 3
SEQ1
SEQ2
BLU
BLK
YEL
YEL
BLU
BLK
BRN
RED
VIO
ORG
TERM BOARD
BLU-MED
RED-LO
BRN
BRNCAP
BLK-HI
GRN/YEL-GND
YEL-COMMON
RED(230V)
BLU(208V)
RED(24V)
BLKCOMM
BRNCOMM
TRAN
FM
C
CR
ON TERMINAL BOARD ABOVE
—17—
A. If the fan will not turn on from the thermostat:
IF THERE IS NO HIGH VOLTAGE TO THE PCB:
1. Check the plug/receptacle connection; this brings power tothe PCB. Make sure the plug is connected properly.
2. Check sequencer number 1 and the plug’s wiring; theyellow wire should be connected to pin number 9 of theplug and the limit switch. A black wire should be connectedto pin number 7 of the plug and to sequencer number 1.
3. Check power leads L1 and L2. If these are not receivingpower, the system cannot function.
IF THE PCB HAS HIGH VOLTAGE APPLIED TO IT:
1. Check the low-voltage transformer leads, R and C. Makesure they are wired to the correct locations. Note thatFig. 13 shows wiring of the HK61GA001 board.
2. Check the output voltage of the secondary side, R and C, ofthe transformer. If the circuit board is a HK61GA003, makesure the ground strap is in place from C to the bracket. Thisstrap must be in place to complete the 24-v circuit. Makesure the transformer output is around 24-v ac. If thetransformer output is zero-v ac and the transformer isreceiving the correct input voltage (208-v or 240-v), thenthe transformer needs to be replaced with the recommendedtransformer. If the transformer output is 24-v ac, thenproceed to 3 and 4.
3. Check the low-voltage fuse shown in Fig. 6 and Fig. 7. Ifthe fuse is blown, replace it. The transformer cannot supplypower to the board with the fuse blown or loose. If the fuseblows when the unit has power applied to it, the systemmost likely has 1 of the following problems:a. If the transformer is shorting out, check the wiring of the
transformer.
b. The maximum load on the transformer is 40 VA. If theload on the transformer is excessive, the low-voltage,5-amp fuse will blow to protect the transformer. If theload exceeds the VA rating of the transformer, a largerVA rated transformer needs to be installed. Check thesequencers for excessive current draw.
c. Check the wiring of the heaters. If the heater is miswired,the fuse may blow. Check the diodes shown in Fig. 14for signs of overheating. If the heater is miswired,correct the miswiring.
4. Check the T1, T2, and T3 connections on the primary sideof the transformer. If they are not connected properly, thelow-voltage terminal board cannot supply the 24-v signal toenergize the fan relay. If the transformer is receiving thecorrect primary voltage but is not outputting the correctsecondary voltage, the transformer needs to be replaced.
B. If the electric heat stages will not turn on but the fanwill turn on:
1. Check the wiring of the sequencer. Pay particular attentionto the high and low-voltage wiring of the sequencers.
2. Check the plug wiring to make sure that it is wiredcorrectly.
3. Check the voltage to the sequencer; sequencer number 1receives a 24-vac signal. If it is receiving the correctvoltage, check to see if the sequencer is closing. If thesequencer is not closing but is receiving the correct voltage,replace the sequencer. If the sequencer is closing, check thehigh-voltage wiring as discussed in 1 and 2.
C. If the electric heat and the fan will not turn on:
IF THERE IS NO HIGH VOLTAGE TO THE PCB:
1. Check the plug connection. This brings power to the PCBtransformer and the fan. Make sure the plug is connectedproperly.
2. Check sequencer number 1 and the plug wiring. The yellowwire should be connected to pin number 9 of the plug andthe limit switch. The black wire should be connected to pinnumber 7 of the plug and to sequencer number 1.
3. Check incoming high-voltage power leads. If these are notreceiving power, the system cannot function.
IF THE PCB HAS HIGH-VOLTAGE APPLIED TO IT:
1. Check the low-voltage transformer leads, R and C. Makesure they are wired to the correct location. The unit will notfunction without proper connections.
2. Check the output voltage of the secondary side, R and C, ofthe transformer. If the circuit board is an HK61GA003,make sure the ground strap is in place from C to the bracket.This strap must be in place to complete the 24-v circuit. Ifthe transformer output is zero-v ac, refer to "If the PCB hashigh voltage applied to it" in column 1, numbers 3 and 4.
D. If the traces are burnt off the back of the PCB:
Usually whenever there is a trace blown on the PCB it meanseither there has been a high-voltage short or high voltage has beenapplied to the low-voltage circuit. This can be prevented bymaking sure the PCB is wired correctly before the PCB has powerapplied to it.
E. If there are blown diodes:
1. If diodes a and b are blown, it is probable the electric heaterplug was miswired. Correct the miswiring. It should benoted the board will need to be replaced if the diodeindicated is bad.
2. If any of the c diodes are blown, the fan is miswired to 1 ofthe low-voltage terminals, AUX1 or AUX2. Check to makesure that the fan leads are connected to the proper terminalsas shown in Fig. 13. If the fan is connected properly, makesure that no other high voltage is applied to the AUXterminals.
F. The PCB fuse keeps blowing:
When the low-voltage fuse blows, it means the transformer wouldhave just blown if the fuse had not been in the circuit to protect it.The fuse usually blows when there is a high current draw on thetransformer, high voltage applied to the low-voltage circuit, or adirect secondary short. When there is a high current draw on thetransformer, it is most likely because the transformer has beenshorted or the system is trying to draw more VA than thetransformer is rated for. When the fuse blows because of highvoltage, the system has mixed high- and low-voltage signals.
1. Check the transformer and thermostat wiring as shown inFig. 11. Make sure the transformer is not shorting out by thethermostat wires being miswired.
2. Check the wiring of the sequencers as shown in Fig. 13.Make sure the low-voltage and the high-voltage wiring areconnected to the proper sequencers.
3. Check the VA draw on the transformer. If the VA draw ismore than the VA rating of the transformer, the fuse willblow. If this is the case, replace the transformer with 1 thathas a higher VA rating and meets system specifications.
G. The fan runs continuously:
1. If the PCB has no low-voltage power, check the blue andblack fan leads. These may be switched at the sequencer.
2. If the PCB has low-voltage power, check the fan relay tosee if it is opening and closing. It may be stuck in thenormally closed position due to debris in the relay.
3. See Service Manager Bulletin (SMB) 92-3.H. Transformer failure:
1. Check the 208-v and 240-v taps connected to T1, and T3.They may be miswired.
—18—
ELECTRIC HEATER FUNCTION ANDTROUBLESHOOTING
This section describes KFA, KFB, KFC, and KFD series electricheaters in exclusion of Smart Heat by examining the functionaloperation of these heaters.
I. DESCRIPTION OF ELECTRIC HEATERCOMPONENTS
A. Limit Switch
The limit switch is a temperature-sensitive control whose functionis to prevent system from overheating in abnormal conditions. Thetemperature settings often vary from heater to heater due tovariations in airflow patterns and element radiant heat conditions.The devices are sized to remain on-line under heat pump condi-tions (115°F air off coil) and minimum CFM, but trip to preventoutlet air conditions above 200°F or excessive component or ducttemperatures.
The device itself consists of a bimetallic disc, which whenoverheated "snaps through" to open a normally-closed high-voltage, high-current switch. When system temperatures coolsufficiently, the switch will automatically reset to its closedposition. Normal failure mode for this switch is open.
If a limit switch has been determined to be defective, NEVERBYPASS THE LIMIT SWITCH. When replacing limit switch,ensure that it is replaced with a limit switch of identical openingtemperature and closing differential. Limits switches are typicallycolor coded to identify their range.
B. KFA and KFB Sequencer
The sequencer is essentially a thermally activated time-delay relaynormally activated by low-voltage control signals from thermostat.The typical sequencer is a 1- or 2-pole normally-open devicewhich energizes within 10 to 30 sec after application of controlsignal and de-energizes 60 to 90 sec after control signal isremoved.
Fig. 14—Control Board Noting DiodesA97033
123
456
789
101112
2FC-1
AUX1
AUX2
DUMMY
DUMMY
DUMMY
COMMON
COMMON
240 VAC 240 VAC
TRANSFORMERAC LINE
RELAY
24VDC
FANEAC2L2T3T2T1
EAC1L1
F4
F3
F2
F1
C
HK61GA001A
W2-
3W
2-E
5 A
MP
F
US
E
MA
XFA
N
TD
B
BLOWNDIODE
(c)
BLOWNDIODE
(a)
BLOWNDIODE
(b)
—19—
In simplistic terms, the sequencers which we use are nothing morethan normally-open limit switches which sit on top of a smallresistive heater. When voltage is applied to this heater, a positivetemperature coefficient resistor (PTC), heat is supplied to abimetallic disc which "snaps through" and closes switch.The time required for PTC to heat to a sufficient point controls ONtiming of device. The time required for disc to cool down whenpower is removed controls OFF time of device. The PTC can bevaried to provide varied timing. Typically a short ON equates to along OFF.Because this is a thermally-activated device, ambient conditionsaffect the ON/OFF cycle. Higher ambient temperature meansshorter ON times and longer OFF times.These sequencers may be "ganged up" to 3 on a common mountingplate to control up to 6 heater elements. In this situation, PTCs aredifferent in each sequencer to provide a staged ON of a minimumof 10 sec between each sequencer — 3 stages of 2 elements sincethe KFA and KFB series heaters use sequencers in which bothswitches of the 2-pole sequencer close simultaneously. Oldermodels used sequencers which had a minimum delay of 10 secbetween each switch.Application of these devices is such that the first switch ON notonly turns on first heater element, but also ensures that indoor fanis energized, because first ON is last OFF. This ensures fanremains ON until the last heater de-energizes.
C. KFC and KFD Electric Heat Relay
KFC and KFD electric heater packages have relays controlling theheater elements instead of sequencers. A small rectifier PCB ismounted to each relay which converts the incoming 24-vac controlsignal to dc. In addition to the rectifier circuit, the second and thirdstage relays contain a time-on delay circuit of 5 seconds for secondstage, and 8 seconds for third stage. When the control signal isremoved from the relays, all relays will open with no time-offdelay.
II. TROUBLESHOOTING KFA, KFB, KFC, AND KFDSERIES ELECTRIC HEATERS
A. Discolored Wire Insulation at Terminal
Check quick-connect terminal at discoloration. Connection may beloose, creating a high resistance through connection point.
B. Fuse Failure
1. Check for shorted wire. Replace wire. Never try to fix wireusing electrical tape.
2. Check shorted element. If element is shorted, replaceheater.
C. No Heat
1. Check fuse for failure. If fuse has failed, refer to FuseFailure section.
2. Check for faulty transformer. Check output voltage oftransformer secondary side R (red) and C (brown). Makesure output is between 18 and 30 vac. If output voltage islow and input voltage tests normal, replace transformer.
3. Check for miswired heater plug harness.
4. Check limit switch or sequencer failure. These switchesshould have failed in open position. If output voltage is zerovolts, replace switch.
5. Check heater relay and PCB (KFC and KFD heaters only).Control voltage input to PCB should be 24-vac. Output torelay should be 18-vdc minimum. If input is present but nooutput, replace PCB. If output is present, replace relay.
D. Heater Will Not Turn Off
1. Check low-voltage wiring for miswire.2. Check for shorted elements to ground.3. Replace sequencer/relays. They may be stuck closed.
E. Nuisance Trips
1. Check for low airflow due to dirty filters, blocked registers,or undersized duct.
2. Check blower motor and wheel for proper operation.Excessive current draw of motor will cause internal over-load to trip.
3. The fan speed may be low.
FAN COIL DESCRIPTIONAND TROUBLESHOOTING
FK4BThe FK4B is similar to the discontinued FK4A as they both haveintegrated controls and motor (ICM) and their own special circuitboard. The greatest difference between the 2 models is the wayeach goes about delivering air.Setting up desired airflow on the FK4B is obtained by theselections made on Easy Select™ circuit board. The motor deliversrequested airflow as defined by signals received from Easy SelectBoard and its internal programming. The major difference is thatthe FK4B motor reacts to changes in system static pressures tomaintain constant airflow.Unlike conventional fan coils where static pressure affects airflow,the FK4B is a constant airflow unit. The blower delivers requestedairflow up to about 0.7 in. of static pressure. The ICM2 ispre-programmed and contains airflows for all modes of operation.Blower characteristics (airflow, torque, and speed-vs-static pres-sure) are known from laboratory testing. If any 3 characteristics areknown, the fourth is defined.Requested airflow is known because of Easy Select board con-figuration and thermostat signals. Torque is known because it isdirectly related to armature current which is measured by motorcontrol. Speed is measured from its generated back EMF. Thisinformation is entered into an expression which calculates torquefrom speed and airflow numbers. If calculation does not matchstored blower characteristics, torque is adjusted every 0.8 sec untilagreement is reached. The unit does not directly measure staticpressure, but does react to a change in static to maintain constantairflow.I. INTEGRATED CONTROLS AND MOTOR (ICM2)
The ICM2 is similar to the ICM1 used in FK4A series units, butcannot be used as a replacement without some modification toFK4A unit. Consult SMB 93-0052 for motor conversion kit. Theelectronics of motor are built into rear of motor, deriving the nameICM. (See Fig. 15.)An ICM is first fed high voltage AC power through the 5-pinconnector. The AC power is then rectified to DC by a diodemodule. After rectification, DC signal is electronically communi-cated and fed in sequential order to 3 stator windings. Thefrequency of communication pulses determines motor speed. Therotor is permanently magnetized.An ICM is powered with high voltage at all times. The motor willnot run with high voltage alone. Low voltage must be applied tocontrol plug to run motor.II. PCB LAYOUT AND DESCRIPTION
NOTE: Layout of actual PCB is depicted in Fig. 16 and 17.The control is a single PCB which interfaces a variable-speedICM2 with other system components.Power for system is supplied from a 230-vac, 60-Hz line. Class 2voltage (24 vac nom.), used for thermostat connections, is derivedfrom a transformer located in close proximity to control. Theprimary and secondary of transformer are connected to controlboard. The 24-vac secondary circuit includes a socket, solderedinto circuit at SEC2, to receive a 5-amp automotive-type fuse.Connection to heater panel is made through 12-circuit connectorP1. Connections to thermostat are made at screw terminals. Linevoltage for ICM2 is made through 7-circuit connector P2. Eighteenquick-connect terminals comprise field select taps for motor.
—20—
Fuse Data: 5-amp automotive-type ATC/ATO (tan)32v200 percent current opening time of 5 sec maximum
A. Electrical Connections
Eighteen 0.187-in quick-connect terminals are used to provideprogramming selections for operating modes of ICM2. The 5selection modes are listed below. For additional information, referto Easy Select Configuration Taps section.
AUX Heat Range—(Violet Wire)AC/HP Size—(Blue Wire)Type—(Orange Wire)AC/HP CFM Adjust—(Black Wire)AC/HP Time Delay—(Grey Wire)
III. SEQUENCE OF OPERATION
A. Continuous Fan Mode
The thermostat closes circuit R to G. The G signal is sent directlyto ICM2.
B. Cooling Mode—Single Speed or 2-Speed High
Thermostat closes circuits R to Y/Y2 and R to O (heat pump only)for single speed. A circuit from R to Y1 is also required for2-speed high. The Y/Y2 signal is sent directly to ICM2.
C. Cooling Mode—Two-Speed Low
Thermostat closes circuits R to Y1 and R to O (heat pump only).The Y1 signal is sent directly to ICM2.
D. Electric Heat Heating Mode
Thermostat closes circuit R to W2, W3, or E.
The terminal block positions W2, W3, and E are tied together byjumpers JW1 and JW2. These jumpers are provided for fieldstaging of electric heater banks through use of thermostats. Whenstaging is a requirement, installer cuts jumpers and wires inthermostats as is the common practice with other fan coils. Toensure motor operation if any 1 of the inputs is energized, the 3electric heater inputs are also interlocked through diodes D1, D2,and D3 to motor W input.
E. Heat Pump Heating Mode—Single Speed or 2-SpeedHigh
Thermostat closes circuit R to Y/Y2 for single speed. A circuitfrom R to Y1 is also required for 2-speed high. The Y/Y2 signalis sent directly to ICM2.
F. Heat Pump Heating Mode—Two-Speed Low
Thermostat closes R to Y1. The Y1 signal is sent directly to ICM2.
G. Heat Pump Heating With Auxiliary Electric Heat
Thermostat closes circuits R to Y/Y2 and/or R to Y1 with R to W2,W3, or E (and R to O in the case of defrost).
See previously described modes for circuit paths.
In the event that electric heating is called for by thermostat whileheat pump is also operating in either heating or defrost mode,
Fig. 15—FK4B, FK4C and FV4A ICM2 MotorA94079
1 2 3 4 5
9
1 2 3 4 5 6 7 8
10 11 12 13 14 15 16
POWER CONNECTOR
CONTROL CONNECTOR
OPTIONAL SAFETY GROUND
OPTIONALSAFETY
GROUND
DO NOT REMOVE
DRAINHOLE
—21—
electric heating signal will appear at motor connector pin 1 asdescribed previously. If necessary, the motor will modify itsairflow output to provide an airflow which is defined as safe foroperation of electric heater.
H. CFM Select Configuration Taps
The CFM Select taps are used by installer to configure system. TheICM2 is capable of discerning wave shapes on some of its inputsand uses this capability to modify its operation to a pre-programmed table of airflows and can be modified in response toother inputs such as the need for de-humidification.
I. ICM2 Control Power
The ICM2 control power is supplied from R circuit throughprinted-circuit runs to motor control connector pin 6, throughmotor control harness to motor. The C side of low-voltage controlpower circuit is connected by printed-circuit runs to motorconnector pins 4 and 5, then through motor control harness tomotor.
J. Low-Voltage Circuit Fusing and Reference
The low-voltage circuit is fused by a board-mounted 5-ampautomotive-type fuse placed in series with transformer SEC2 andR circuit. The C circuit of transformer is referenced to chassisground through a printed-circuit run at SEC1 connected to metalstandoff marked GROUND SCREW REQUIRED.NOTE: A ground screw must be in place or erratic motoroperation can result.K. Transformer, Motor, and Electric HeaterPower Connections
The high-voltage (230-vac) power input to board is providedthrough electric heater connector pins 7 and 9. The high voltage isthen connected through printed-circuit runs to motor power con-
nections M1 and M2 and transformer power connections T1 andT3. Transformer connection T2 is a dummy terminal used forunused primary power lead. The transformer secondary connec-tions are made at SEC1 and SEC2 connectors.
IV. EASY SELECT CONFIGURATION TAPS
The Easy Select taps are used by installer to configure system. TheICM2 uses selected taps to modify its operation to a pre-programmed table of airflows. Airflows are based on system sizeor mode of operation and those airflows are modified in responseto other inputs such as the need for de-humidification.(See Fig. 16.)
The FK4B Fan Coil must be configured to operate properly withsystem components with which it is installed. To successfullyconfigure a basic system (see information printed on circuit boardlocated next to select pins), move the 5 select wires to pins whichmatch components used.
A. Auxiliary Heat Range
The installer must select the auxiliary heat airflow approved forapplication with kw size heater installed. If no heater is installed,skip this step. Each select pin is marked with a range of heaters forwhich airflow (also marked) is approved. For increased comfortselect the narrowest kw range matching the heater size, forexample, 0-10 for a 10-kw heater. This airflow must be greaterthan the minimum CFM for electric heater application with thesize system installed for safe and continuous operation. Note thatairflow marked is the airflow which will be supplied in emergencyheat mode and heating mode on air conditioners when electric heatis primary heating source. To ensure safe heater operation in heatpump heating mode when electric heaters are energized, the ICM2
Fig. 16—Easy Select BoardA94076
EASY SELECT
GROUNDSCREW
REQUIRED
L
R
C
O
Y/Y2
Y1
GE
CES0130007–00
D8 D7 D5 D6
P1
D1
D2 D9 D4
R2HEATER
240VAC
T2
T3
M2
M1
T1XFORM
MOTOR
240VAC
SEC2 SEC1
24VAC
D3
P2
R3
JW3
JW4
AUX2
AUX1 HUM1
HUM2
24VDC
JW1
JW2D11
R1
CES
S430
023–
01C
EBD
4300
23–0
1
D10
FS1
5 AMPMAX ST1
RED
MOTOR
AMP 12-PIN MATE-N-LOCKCONNECTOR (1)
3⁄16-IN. MALEFASTON
AMP–TYP(21) PLCS
MOLEX 7-PINCONNECTOR (1)
LOW VOLTAGETERMINAL BLOCK
W2-E JUMPER3RD STAGE
W2
W3 W2-W3 JUMPER2ND STAGE
PRINTED CIRCUITBOARD
1⁄4-IN. MALEFASTONAMP–TYP(9) PLCS
AUX HEAT RANGE
AC/HP SIZE
TYPE
AC/HP CFM ADJUST
DELAYAC/HP TIMEENH
VIO
ORN
BLK
GRY
BLU
ON
OFF
0
90
30
90
0
0
HIMEDLO
HP-EFFHP-COMFORTAC
KW
CFM
0-30
1200
0-20
1000
0-10
800
0-5
600
042 036 030 024
5
—22—
will run the higher of heat pump efficiency airflow and electricheater airflow. The factory selection is largest heater rangeapproved. (See Fig. 16.)
B. AC/HP Size
The factory setting for air conditioner or heat pump size is largestunit meant for application with model of fan coil purchased. Theinstaller needs to select air conditioner or heat pump size to ensurethat airflow delivered falls within proper range for size of unitinstalled in all operational modes. (See Fig. 16.)
C. System Type
The type of system must be selected.
1. AC—air conditioner
2. HP-COMFORT—provides same airflow as air conditionerselection (approximately 375 CFM/ton)
3. HP-EFF—provides most efficient airflow for heating andcooling modes (approximately 410 CFM/ton heating and375 CFM/ton cooling)
The factory setting is AC. (See Fig. 16.)
D. AC/HP CFM Adjust
Select low, medium, or high airflow. To provide any of theseairflows, AC/HP ADJUST select must be moved to MED position.The factory selection is LO. The adjust selections HI/LO willregulate airflow supplied for all operational modes, except non-heat pump heating modes, +10 percent and -10 percent respec-tively. The adjust selection options are provided to adjust airflowsupplied to meet individual installation needs for such things asnoise, comfort, and humidity removal. (See Fig. 16.)
E. AC/HP Time Delay
Select desired time delay profile. Four motor operation delayprofiles are provided to customize and enhance system operation.(See Fig. 16.) The selection options are:
1. The standard 90 sec off delay (factory setting).
2. No delay option used for servicing unit or when a thermo-stat is utilized to perform delay functions.
Fig. 17—Easy Select Board CircuitryA94077
ST1
E8
ST1
W29
ST1
W310
ST1
C3
ST1
R2
ST1
G7
ST1
Y/Y25
ST1
Y14
ST1
L1
ST1
O3
JW2
JW1
JW3
JW4
D1
D2
D2
R3
1K 2W
SEC1
SEC2 PS1
R2
1K 2W
R1
1K 2W
P11 2 3
4 5 6
7 8 9
10 11 12
HIGH VOLTAGE
M1
T1
T2
M2
T3
AUX1
HUM1
AUX2
HUM2
D7
D8
D9
D4
D5
D6
P2
W/W1GC1C2RY/Y2Y1
D11
D10
5 – 301200
5 – 201000
5 – 10800
0 – 5600
REDQC19
QC4
QC8
QC3
QC7
QC2
QC6
QC1
QC5
024030036042
QC9
AC
QC12
QC15
ONOFF
LOW
090
QC13MED
QC10HP–COM.
QC11HP–EFF.
QC14HI
QC16
3090
QC17
3030
QC18
00
AUX. HEATRANGE
AC/HPSIZE
AC/HPTYPE
AC/HPCFM TRIM
AC/HPDELAY
—23—
3. A 30 sec on/90 sec off delay profile used when it isdesirable to allow system coils time to heat up/cool downprior to airflow. This profile will minimize cold blow inheat pump operation and could enhance system efficiency.
4. ENH, enhanced selection provides a 30 sec on/180 sec offdelay at half airflow, adding comfort and efficiency.
V. TROUBLESHOOTING PCB
Use Fig. 17 and 18 and Tables 3, 4, and 5 as guides introubleshooting PCB unless otherwise noted.
A. If Fan Will Not Turn On From Thermostat:
IF THERE IS NO HIGH VOLTAGE TO PCB:
1. Check connection of 12-pin plug from heaters to receptacleon Easy Select board. This supplies power to PCB. Be sureplug is connected properly.
2. Check sequencer number 1 and plug wiring. Yellow wireshould be connected to pin number 9 of plug and to limitswitch. Black wire should be connected to pin number 7 ofplug and to sequencer number 1.
TABLE 3—MALE/FEMALE QUICK-CONNECT TERMINALS (FK4B)
SIZE FEMALE SIZE MALE DESCRIPTION
0.250 X 0.032
M2 Motor line voltage connection (230 vac 60 Hz)T3 Transformer line voltage connection (230 vac 60 Hz)T2 Transformer tap storage terminal for 208-vac lead
SEC1 Secondary connection from transformer (24 vac)This connection is common to chassis ground through eyelet marked GROUND SCREW REQUIRED.SEC2 Secondary connection from transformer (24 vac)HUM1 Low voltage ground for humidifier option (24 vdc)HUM2 Low voltage output for humidifier option (24 vdc)AUX1 Low voltage ground for auxiliary option (24 vdc)AUX2 Low voltage output for auxiliary option (24 vdc)
0.187 X 0.032M1 Common connection to blower motorT1 Common connection for transformer
RED Common to R screw terminal and SEC2
TABLE 4—CONNECTIONS ON SINGLE BARRIER STRIP MOUNTED, CROSS SLOTTED, CAPTIVE BINDING HEAD (FK4B)
SCREWTERMINAL DESCRIPTION
W2 Connection for W2 signal from thermostatW3 Connection for W3 signal from outdoor thermostatE Connection for E signal from thermostat
Y/Y2 Connection for Y signal from thermostatG Connection for G signal from thermostatO Connection for O signal from thermostat
L This connection is a field termination for use in connecting L lines of thermostat and outdoor unit together. There is noconnection of this terminal with control circuity.Y1 Connection for low-speed compressor operationR Connection for R signal to thermostat (24 vac)C Connection for C terminal to thermostat (24 vac common)
TABLE 5—CONNECTIONS AND CONNECTOR (FK4B)
TYPECONNECTION
TYPECONNECTOR PIN NO. DESCRIPTION
HeaterConnection 12-Pin
Pin 1 Common to E screw terminalPin 2 Common to W2 screw terminalPin 3 Common to C screw terminal, SEC1 terminal, and chassis groundPin 4 Common to C screw terminal, SEC1 terminal, and chassis groundPin 5 No connectionPin 6 Common to W3 screw terminalPin 7 Common to M2 and T3 quick-connects, 230 vac inputPin 8 No connectionPin 9 Common to M1 and T1 quick-connects, 230 vac input
Pin 10 No connectionPin 11 No connectionPin 12 No connection
ICM2 Motor 7-Pin Header
Pin 1 Diode OR output of E or W3 or W2 thermostat signalsPin 2 Thermostat G signalPin 3 Common to C, SEC1, and chassis groundPin 4 Common to C, SEC1, and chassis groundPin 5 Common to R and SEC2 (via 5-amp fuse)Pin 6 Thermostat Y/Y2 signalPin 7 Thermostat Y1 signal
—24—
Fig. 18—FK4B Wiring DiagramA94078
LSICMTRANGNDFURECPCBF
SEE RATING PLATEFOR VOLTS & HERTZ
(SEE NOTE 1)
FIELD POWER WIRING
YEL
GND
30KW 1PH SCHEMATIC DIAGRAM
DISCONNECT PER NEC
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICINGNOT SUITABLE FOR USE ON SYSTEMS
EXCEEDING 150V TO GROUND
CAUTION:
ATTENTION:NE CONVIENT PAS AUX INSTALLATIONS
DE PLUS DE 150 V A LA TERRE
BLOWER MOTORROTATION
HVTB
SEQ 3
CB/FU4
FU6YEL
YEL
YEL
L1
12 11BLK BLK
FU5
8 7
CB/FU2 CB/FU1
YEL YEL 4 3BLK BLK
10 9BLKBLK
SEQ 2
6 5
YEL 2 1BLK
CB/FU3
L2
HTR6
HTR5
HTR4
HTR3
HTR2
HTR1
LS6
LS5
LS4
LS3
LS2
LS1
BLK
SEQ 1
YEL
YEL
BLK BLK
BLK BLK
BLK
BLK
BLK
BLU
BLKYEL
BLU
PLUG 1 RED
GRY
BR
NB
RN
SEQ1
SEQ2
SEQ3
ORN VIO
123456789101112
24567
FIELD POWER WIRING DISCONNECT PER NEC
SCHEMATIC DIAGRAM
SEE RATING PLATEFOR VOLTS & HERTZ
(SEE NOTE 1)YEL BLK
9 7
GND
COOLING CONTROL WIRING
COOLING CONTROL ONLY
AUX HEAT RANGE
AC/HP SIZE
TYPEA–C HP–COMFORT HP–EFF
AC/HP CFM TRIM
AC/HP DELAY ON/OFF0/30 30/30 30/30 0/0
7
RECP 21
TRAN
COMMON
BRN
RED
BLK
RED
GRY
BLK
ORN
BLU
VIO
1
2
3
4
5
6
7
8
9
10
11
12
RECP 1
REDBLU
RED
M1
M2
T1
SEC2
SEC1
T2
T3 PCB
PLUG
24VAC
LVTB
JW2
JW1
L
R
C
O
G
E
W2
W3
GRN/YEL
YEL
BLK
5 4 3 2 1
PLUG 3
PLUG 4
YEL
RECP 3
RECP 4
ICMBRNYEL
REDVIO
REDORN
BRNVIO
ORNGRY
BLUBLK
BLK
1
9
2
10
3
11
4
12
5
13
6
14
7
15
8
16
PLUG 2
BLK
YEL ORN GRN
RED BRN VIO
(SEE NOTE 3)
(SE
E N
OT
E 2
)