Water Heaters

Graham has engineered two different styles of indirect fired instantaneous water

heaters to meet the stringent demands of both comfort and process hot water

heating. As a result, Graham MicroMix II and MicroMax I produce the precise

amount of water, at the right temperature, under widely varying demands. This

outstanding performance is confirmed by the many installations in hospitals,

schools, hotels, restaurants, laundries, ships, factories and food plants.

The MicroMix II and MicroMax I use a unique feed-forward temperature control

system to instantly produce hot water within +/- 4˚ F of the set temperature. The feed-forward design is the only true instantaneous water heater because the water

temperature is controlled at the demand point, which is after the heat exchanger.

MicroMix II and MicroMax I are instantaneous water heaters that use the most

efficient method of heat transfer available, making them very compact. They need

only 6 square feet of floor space and can easily fit where any man can. No storage

tank is required, and energy savings as high as 40 percent can be realized. The

MicroMix II is a steam-to-water heater utilized when steam is available for

heating, and the MicroMax is a boiler water-to-water heater used when high

temperature boiler water is the heating medium.

Graham and Spirax Sarco have partnered under a private label agreement for the

sale of our instantaneous steam water heaters.

The Graham MicroMix (MM) is privately labeled by Spirax Sarco under the brand

name RediHeat (RH).

Graham has engineered two different styles of indirect fired

instantaneous water heaters to meet the stringent demands

of both comfort and process hot water heating. As a result,

Graham MicroMix® II and MicroMax* produce the precise

amount of water, at the right temperature, under widely

varying demands. This outstanding performance is

confirmed by the many installations in hospitals, schools,

hotels, restaurants, laundries, ships, factories and food plants.

The MicroMix II and MicroMax use a unique feed-forward

temperature control system to instantly produce hot water within

+/- 4˚ F of the set temperature. The feed-forward design is the only true

instantaneous water heater because the water temperature is controlled

at the demand point, which is after the heat exchanger.

MicroMix II and MicroMax are instantaneous water heaters that use the most efficient method of heat transfer

available, making them very compact. They need only 6 square feet of floor space and can easily fit where any

man can. No storage tank is required, and energy savings as high as 40 percent can be realized.

The MicroMix II is a steam-to-water heater utilized when steam is available for heating, and the MicroMax is a

boiler water-to-water heater used when high temperature boiler water is the heating medium.

Mic

ro

Mix

II / M

ic

ro

Ma

x P

erfo

rm

an

ce

a

nd

R

elia

bility

2

Designed for performance

Engineered for reliabilityWith the MicroMix II and MicroMax, Graham has built a better water

heater by making it easy to use, simple to maintain and resistant to the

harsh service of varying demand.

Simple Mechanical Design: Water temperature is controlled by

a mechanical blending valve that operates based on demand so

there are no extraneous power sources, controls or temperature

sensors required.

“Hands-Free” Design: The feed-forward system has been used for more

than 40 years to guarantee the continuous steady flow of hot water with

a minimal amount of maintenance.

Heavy Duty: The MicroMix II features the proven Graham spiral-tubed

Heliflow®

heat exchanger for converting steam to hot water. Its rugged

casing and bourdon tube configuration allow the entire assembly to

expand and contract without localized stresses, making them perfect

for the intermittent cycling they are subject to.

Flexible: The MicroMax employs a plate heat exchanger with removable

heat transfer plates to convert the boiler water to hot water. This makes

for fast, easy maintenance and allows for adding plates to increase the

capacity of the heater at a later date if necessary.

Anti-Bacterial: Feed-forward design requires no water storage and overheating of the domestic water in the heat

exchanger prior to the blending valve. This produces a double-edged bacteria-busting effect and reduces the risk

of legionella and other contaminants.

Security: The blending valve is designed in such a way to be fail-safe. Potential failure or damage to the unit will

produce only cold water.

*MicroMax is patent pending

High Efficiency: The corrugated heat transfer plates

and counter-flow arrangement in the MicroMax

produce heat transfer rates that are 5 times higher

than with tubular surfaces used in other water

heaters. The result is a smaller package with less

boiler water usage. The boiler water to potable water

flow can be as low as 1 to 1 in a MicroMax water

heater, compared with 4 to 1 for a conventional type.

Scale Prevention: Plate heat exchangers, as used in

the MicroMax, substantially reduce the risk of scale

by constantly redirecting the flow against the heat

transfer plates, scouring them clean of most scale or

biological buildup. For extreme cases, disassembly

of the plate pack allows for easy cleaning.

Flexible: The gasketed plate construction allows for

the simple addition or removal of plates to handle

future hot water demands. It also makes the

MicroMax the easiest water heater to service.

Safe: Optional double-wall plates can eliminate

the risk of cross-contamination between boiler

and domestic water.

Mic

ro

Ma

x F

ea

tu

re

s a

nd

B

en

efits

3

MicroMax

HotWater

ColdWater Supply

HotWater Return

HeatedWater

MicroMax

How it works:

1. The heat source is properly connected to the heat exchanger of the appropriate package – steam for the MicroMix II and

boiler water for the MicroMax.

2. The water to be heated is piped to the water heater inlet, where it is directed to both the cold port of the blending valve and

the heat exchanger. The heat exchanger heats the water to the required temperature before sending it to the hot port of the

blending valve for mixing.

3. The blending valve has a proportional valve plug regulated by the movement of the diaphragm, which is induced by

pressure differentials in the sensing head.

4. A sensing line “loads” the top portion of the diaphragm with supply line cold water pressure while blended water outlet

pressure is being sensed below.

5. Flow demand creates a pressure imbalance above (+) and below (-) the diaphragm, resulting in movement of the diaphragm

and proportioning plug.

6. The movement aligns ports in the plug with supply ports in the valve body, introducing the correct proportion of hot and cold water.

7. This action automatically generates blended hot water through all rated flow capacities at the chosen preset temperature (+/- 4 ̊F).

8. The integral fail-safe system permits stem travel in the event of plug restriction or parts failure, opening an auxiliary cold

water port. Cold water flooding yields cooler water or, in parts failure, no water at all.

9. Temperature is easily adjusted by side-to-side movement of the control rod on the valve body. Stabilization adjustments are

made during the initial startup by rotation of the control rod.

Boiler Water-to-Water Heater

Mic

ro

Mix

II F

ea

tu

re

s a

nd

B

en

efits

4

MicroMix® II

Longer Life: The Heliflow heat exchanger has helically

coiled tubes that are free to expand and contract with

temperature changes. This protects the heat exchanger

from the constant cycling that can exist with

instantaneous heating.

Compact: The tubes in the Heliflow are coiled to

minimize space requirements while providing proper

steam distribution. This makes the MicroMix II the

smallest instantaneous water heater available.

Heavy Duty: The rugged cast construction and brazed

tube joints make the Heliflow more durable than any

other heat exchanger (i.e., shell and tube or plate type)

for condensing steam service.

Easy Maintenance: When maintenance on the Heliflow

is required, the coiled bundle can be cleaned in place,

removed for cleaning or replaced in minimal space.

Safe: Optional double-wall tubes can eliminate

the risk of cross-contamination between steam

and domestic water.

Boiler

HotSteam

HeatedWater

CondensateReturn

MicroMix II

ColdWaterSupply

Steam-to-Water Heater

PressureSensing Line

HotWater In

ColdWater In

TemperatureControl Rod

ProportioningPlug with

Safety Port

Mic

ro

Ma

x S

pe

cific

atio

ns

5

Model MX15 MX30 MX45 MX60 MX75 MX90 MX105 MX120

Performance

Maximum flow rate (gpm) 15 30 45 60 75 90 105 120

Capacity Heat 40˚ F water up to 140˚ F. Outlet temperature adjustable.

Consult Graham for double-wall or other capacities.

Boiler water temperature 180˚ F to 210˚ F

Boiler water flow Boiler water to potable water flow: 2.0 / 1.0 for 180˚ F to 1.0 / 1.0 for 210˚ F

Connections – Size – NPT

Potable water in/out (in.) 2 2 2 2 2 / 2.5 2 / 2.5 2 / 2.5 2 / 2.5

Boiler water in/out (in.) 2 2 2 2 2 2 2 2

Connection Material Potable water: steel; boiler water: steel

Heat Exchanger Construction Painted steel frame, 316SS thermal plates, nitrile gaskets

Optional construction 316SS connections, EPDM gaskets

Control Valve Instantaneous type; blending by mechanical means only based on

pressure differential; fail in cold position

Materials Bronze body, Hastelloy valve plug, neoprene diaphragm.

Option: 316SS valve/piping

Piping Quick disconnect Victaulic fittings; integral pressure relief valve

Design 150 psi potable water side / 150 and 300 psi boiler side / ASME certified

Accessories Boiler water inlet/outlet manual control valves and pressure gauges.

Temperature gauges for boiler inlet water and potable water outlet.

Optional Construction Double-wall plate construction, water recirculation package, hot water shut-

off system – solenoid controlled, boiler/potable water booster pump package

Dimensions

Height (in.) 35 35 35 35 35 35 35 35

Width (in.) 23 23 23 23 25 25 25 25

Length (in.) 34 34 34 34 56 56 56 56

MicroMax

Boiler

Water-to-Water

Heater

Model MX-ab

a = nominal flow in gpm (15, 30, 45, 60, 75, 90, 105, 120)

b = special construction (D = double-wall, E = EPDM gaskets)

Specifications

Mic

ro

Mix

II S

pe

cific

atio

ns

6

Model MM-30 MM-60 MM-90 MM-120

Performance

Maximum flow rate (gpm) 30 60 90 120

Capacity Heat 40˚ F water up to 140˚ F. Outlet temperature adjustable.

Consult Graham for double-wall or other capacities.

Steam pressure 5 to 15 psig standard, 20 to 250 psig requires pressure regulator (H package)

Steam flow Approximately 50 lbs./hr. per 1 gpm of water heated

Connections – Size – NPT

Potable water in/out (in.) 1.5 / 2 2 2.5 2.5

Steam in/condensate out (in.) 3 / 1.25 3 / 2 4 ANSI / 2 4 ANSI / 2

Connection Material Potable water: brass; steam: cast iron

Heat Exchanger Construction Painted steel/cast iron casing, copper tubes

Optional construction Tubes in admiralty, 70/30 cu.ni. or 316SS

Control Valve Instantaneous type; blending by mechanical means only based on

pressure differential; fail in cold position

Materials Bronze body, Hastelloy valve plug, neoprene diaphragm.

Option: 316SS valve/piping

Piping Quick disconnect Victaulic fittings; integral pressure relief valve

Design 150 psi potable water side / 50, 75 and 150 psi steam side / ASME certified

Accessories Steel frame, condensate traps and strainers (main and drip), steam inlet

pressure gauge, water outlet temperature gauge

Optional Construction Double-wall construction, water recirculation package, hot water shut-

off system – solenoid controlled, potable water booster pump package

Dimensions

Height (in.) 21 22.5 33 33.5

Width (in.) 22.5 25 23.5 24.5

Length (in.) 31.5 31.5 31.5 39

MicroMix® II

Steam-to-Water

Heater

Models MM-abc

a = nominal flow in tens of gpm (3 = 30, 6 = 60, 9 = 90, 12 = 120)

b = tube material (0 = copper, 1 = admiralty, 2 = 70/30 cu.ni., 6 = 316SS)

c = special construction (D = double-wall, H = high pressure steam with regulator, S = cast steel shell)

Specifications

RediHeat Instantaneous Water HeaterReliable, durable, and simple to operate

spiraxsarco.com/us

Designed for performanceThe Spirax Sarco RediHeat is a steam to water heater that incorporates a unique feed-forward temperature control system to instantly produce hot water within +/-4ºF of the set temperature under widely varying demands. This outstanding performance makes the RediHeat the ideal solution for hot water applications where tight temperature control and instant response to changes in demand are required.

Engineered for reliabilityThe RediHeat is quick to install, easy to use, simple to maintain and resistant to the harsh service of varying demand loads.• Simple Mechanical Design: Water temperature is

controlled by a mechanical blending valve that operates based on demand. A manual adjustment compensates for seasonal changes in cold water supply temperature. The unit requires no extraneous power sources, controls or temperature sensors making installation a snap!

• Energy Efficient: The RediHeat only consumes energy when responding to demand. This mode of operation can save as much as 40% in energy costs when compared to a hot water tank system.

• Security: The blending valve has a fail-safe design – vital for domestic hot water applications. Potential failure or damage to the unit will produce only cold water. Consumers can never be exposed to hot water at temperatures above set point. Optional double-wall tubes are available to eliminate the risk of cross contamination between steam and water.

• Heavy Duty: The RediHeat features a spiral tubed helical heatexchangerforefficientheattransferinacompactspace.Theruggedcasingandbourdontubeconfigurationallows the entire assembly to expand and contract without localized stressing, ideal for intermittent cycling common with domestic hot water applications.

• Self-Descaling: When the coil expands with changing temperature, any scale that has hardened on the inside of the tubes is broken up by the changing shape of the coil.

• Anti-Bacterial: The perfect environment for the growth of legionella bacteria is stagnant water between 68ºF and 122ºF. The presence of scale and sediment only expedites colonization. With the RediHeat feed-forward design, water is over-heated to 160ºF - 200ºF in the heat exchanger

before being blended (in response to demand) with incoming cold water to the desired output temperature. In this way the presence of stagnant water at bacteria-friendly temperatures is eliminated.

• Compact: With a footprint of only 6.5 square feet and a height of 33.5” for the largest unit, the RediHeat is the most compact instantaneous water heater available – important when space is at a premium.

• Easy Maintenance: When maintenance on the helical heat exchanger is required, the coiled tube bundle can be either cleaned in place or removed for cleaning. Due to the helical design removal is easy and does not require the withdraw space typical with other shell and tube designs.

How it works1. The water to be heated is piped to the water heater inlet

where it is divided and directed to the cold port of the blending valve and the heat exchanger.

2. The heat exchanger heats the water before sending it to the hot port of the blending valve for mixing with cold water to be the required temperature.

3. The blending valve has a proportional valve plug that is regulated by movement of the diaphragm, which is induced by pressure differentials in the sensing head.

4. A sensing line “loads” the top portion of the diaphragm with supply line cold water pressure while blended water outlet pressure is being sensed below.

5. Flow demand imparts a pressure imbalance above (positive) and below (negative) the diaphragm resulting in movement of the diaphragm and proportioning plug.

The Spirax RediHeat Advantage• AllRediHeataredesignedtoandstampedASMESectionVIII. •Everyblendingvalveisoperationally(wet)testedpriortoshipment.

For more information contact your local Spirax Sarco representative.

Spirax Sarco, Inc 1150 Northpoint BlvdBlythewood, SC 290161-800-883-4411

STR1021

6. The movement aligns ports in the plug with supply ports in the valve body, introducing the correct proportion of hot and cold water.

7. This action automatically generates blended hot water throughallratedflowcapacitiesatthechosenpresettemperature (+/- 4ºF).

8. The integral fail-safe system permits stem travel in the

event of plug restriction or parts failure, opening an auxiliarycoldwaterport.Coldwaterfloodingyieldscoolerwateror,inthecaseofpartsfailure,zeroflow.

9. Temperature is easily adjusted by side-to-side movement of the control rod on the valve body. Stabilization adjustments are made during the initial startup by rotation of the control rod.

RediHeat Model RH-30 RH-60 RH-90 RH-120PerformanceNominal maximum output (gpm) 30 60 90 120

Capacity Heat 40 ºF water up to 140 ºF.Outlet temperature adjustable.

Steam inlet pressure 10 to 15 psig standard20 to 250 psig requires pressure regulator (H package)

Steamflow Approximately 50 lbs/hr per 1 gpm of water heated.

Water inlet pressure 30 to 150 psig (must be at least 15 psi above steam pressure for correct operation)

Connections (NPT)Potable Water: In – Out 2½” 1½” 2” 2” 2½” 2½”

Steam In - Condensate Out 3” 1¼” 3” 2” 4” ANSI 2” 4” ANSI 2½”

MaterialsofConstruction

Steam side piping Steel

Potable water side piping Brass

HeatExchanger(standard) Cast iron shell, copper tubes

HeatExchanger(options) Cast steel shellTubes: admiralty, 70/30 Cu Ni, 316SS & Double Wall (copper only)

BlendingValve Bronze body, Hastalloy valve plug, Neoprene diaphragm

DesignBlendingValve Instantaneous: responds to pressure differential

Fail-safe (cold)Integral pressure relief valve

Piping QuickdisconnectVictaulicfittings

Pressure Potable water side: 150 psiSteam side: 50 psi (RH-90 & RH-120), 75 psi (RH-30 & RH-60)

Certification ASMESectionVIII

AccessoriesStandard Steel frame, condensate traps & strainers (main & drip), steam inlet pressure gauge, water outlet temperature gauge

Optional “H” (pressure reducing) package, angle iron stand, water recirculation package, solenoid controlled hot water shut-off system, thermal insulation blanket, OSHA cover, acid pump cleaning system

Nominal Dimensions (inches)

Height 21 22½ 33 33½

Width 22½ 25 23½ 24½

Length 31½ 31½ 31½ 39

Engi

neer

ed

Prod

ucts

9:538TI-12-008-US 3.13

Local regulations may restrict the use of this product below the conditions quoted. Limiting conditions refer to standard connections only.In the interests of development and improvement of the product, we reserve the right to change the specification.

RediHeat Instantaneous Water Heater

DescriptionThe RediHeat is a steam (shell side) to water (tube side) heat exchange package that incorporates a unique feed-forward temperature control system to instantly produce hot water within +/-4ºF of the set temperature under widely varying demands. This outstanding performance makes the RediHeat the ideal solution for domestic hot water applications where tight temperature control and instant response to changes in demand are required.

Temperature ControlWater temperature is controlled by a mechanical blending valve that operates based on demand. A manual adjustment compen-sates for seasonal changes in cold water supply temperature. The blending valve has a fail-safe design ensuring consumers can never be exposed to hot water at temperatures above set point – vital for domestic hot water applications. Potential failure or damage to the unit will produce only cold water.

Heat ExchangerThe RediHeat features a spiral tubed helical heat exchanger for efficient heat transfer in a compact space. The coiled tube technol-ogy does not require tube supports allowing the tubes to be in very close proximity resulting in a more compact heat transfer bundle. The helical design of the coil allows it to expand and contract with temperature change such that any scale that has hardened on the inside of the tubes is broken up by the changing shape of the coil. The rugged casing and bourdon tube configuration also allows the entire assembly to expand and contract in response to temperature change without localized stressing. This is ideal for intermittent cycling that is common with domestic hot water applications.

Efficiency The typical domestic hot water system only places a demand on the heat exchanger 15% of the time. The feed forward design of the RediHeat only consumes energy when responding to demand. With no hot water storage required, this mode of operation can save as much as 40% in energy costs when compared to a hot water tank system.

Anti-BacterialThe perfect environment for the growth of legionella bacteria is stagnant water between 68ºF and 122ºF. The presence of scale and sediment only expedites colonization. With the RediHeat feed-forward design, water is over-heated to 160ºF - 200ºF in the heat exchanger before being blended (in response to demand) with incoming cold water to the desired output temperature. In this way the presence of stagnant water at bacteria-friendly temperatures is eliminated.

Recirculation SystemA problem many hot water systems encounter is the delayed sup-ply of hot water to fixtures that are a substantial distance from the heater. During idle periods, heat loss in the piping system will result in cool water at the faucet until hot water produced from the heater is able to reach that point. Delays in providing hot water at the faucet can result in user dissatisfaction. To provide instantaneous

hot water on demand in systems with long pipe runs a recirculation system incorporating a pump (not included) to maintain con-stant flow should be installed. The RediHeat recirculation system maintains loop temperatures by measuring the temperature of the returning hot water and, dependent on temperature, either passing it back through the heat exchanger for re-heating or diverting it back to the hot water loop.

InstallationWith a footprint of only 6.5 square feet and a height of 33.5” for the largest unit, the RediHeat is the most compact instantaneous water heater available – important when space is at a premium. The unit requires no extraneous power sources, controls or temperature sensors making installation quick and simple. The RediHeat may be wall or floor stand mounted or can be suspended from the ceiling. Approximately 3' clearance from the floor is required to allow room for steam and condensate connections and the hot water outlet. An optional angle iron stand is available and recommended for floor mounting. For optimal heater performance, the steam trap should discharge to 0 psig, below the level of the trap. If lift of condensate is required or the trap must discharge to a back pressure, an automatic pump trap (APT) should be fitted for correct operation. Contact Spirax Sarco for details. The steam inlet pressure to the heat exchanger is limited to 15 psig. Greater steam supply pressures require installation of a pressure regula-tor. A pressure relief valve set at 75 psig (for RH-30 & RH-60) or 50 psig (for RH-90 & RH-120) should be installed in the steam inlet pipe downstream of the pressure regulator if steam pressure to the heat exchanger can exceed these limits. Acceptable cold water inlet pressure range is 30 to 150 psi. Water pressure must be at least 15 psi greater than steam pressure for correct operation. The RediHeat incorporates an integral pressure relief valve (located on side of the blending valve) to relieve excess water pressure caused by thermal expansion.

Engi

neer

ed

Prod

ucts

9:539

TI-12-008-US 3.13

Spirax Sarco, Inc., 1150 Northpoint Blvd, Blythewood, SC 29016 Telephone: (803) 714-2000 FAX (803) 714-2222

RediHeat Instantaneous Water Heater

MaintenanceWhen maintenance on the helical heat exchanger is required, the coiled tube bundle can be either removed for cleaning or cleaned in place. Due to the helical design, removal is easy and does not require the withdraw space typical with other shell and tube designs. An acid pump cleaning system is available for cleaning the coil in situ when poor water quality can result in scaling.

Typical SpecificationThe domestic hot water heater shall be a Spirax Sarco RediHeat steam-fired, instantaneous water heater incorporating feed forward temperature control to instantly produce hot water within +/-4ºF of the set temperature under widely varying demands. The unit will incorporate an ASME code stamped helical coil heat exchanger and blending valve. The coiled tube bundle must be capable of being removed for inspection and service with-out breaking steam connections or removing the unit from its installed position. The unit shall be completely self-contained and require hook-up only to steam and water. There shall be no electric or pneumatic requirements. Each heater shall be a factory assembled package with the capacity to heat ___ gpm of water from __ to ___ degrees Fahrenheit without the use of thermostatic control devices or storage tanks. Supply steam pressure is ___ psig.

RediHeat Model RH-30 RH-60 RH-90 RH-120

Performance

Nominal maximum output (gpm)

30 60 90 120

CapacityHeat 40 ºF water up to 140 ºF. Outlet temperature adjustable.

Steam inlet pressure10 to 15 psig standard20 to 250 psig requires pressure regulator (H package)

Steam flow Approximately 50 lbs/hr per 1 gpm of water heated.

Water inlet pressure 30 to 150 psig (must be at least 15 psi above steam pressure for correct operation)

Connections (NPT)

Potable Water: In – Out 1½” 2” 2” 2½” 2½”

Steam In - Condensate Out 3” 1¼” 3” 2” 4” ANSI 2” 4” ANSI 2½”

Materials of Construction

Steam side piping Steel

Potable water side piping Brass

Heat Exchanger (standard) Cast iron shell, copper tubes

Heat Exchanger (options)Cast steel shellTubes: admiralty, 70/30 Cu Ni, 316SS & Double Wall (copper only)

Blending Valve Bronze body, Hastalloy valve plug, Neoprene diaphragm

Design

Blending ValveInstantaneous: responds to pressure differentialFail-safe (cold)Integral pressure relief valve

Piping Quick disconnect Victaulic fittings

PressurePotable water side: 150 psiSteam side: 50 psi (RH-90 & RH-120), 75 psi (RH-30 & RH-60)

Certification ASME Section VIII

Accessories

Included with RediHeat Steel frame, steam inlet pressure gauge, water outlet temperature gauge

Required (not included) Main and Drip traps plus strainers

Optional"H" (pressure reducing) package, angle iron stand, recirculation package, solenoid safety shut-off system, thermal insulation blanket, OSHA cover, chemical cleaning system

Nominal Dimensions (inches)

Height 21 22½ 33 33½

Width 22½ 25 23½ 24½

Length 31½ 31½ 31½ 39

Engi

neer

ed

Prod

ucts

9:536TI-12-007-US 3.13

Local regulations may restrict the use of this product below the conditions quoted. Limiting conditions refer to standard connections only.In the interests of development and improvement of the product, we reserve the right to change the specification.

Sizing RediHeat Instantaneous Water Heaters

Use the tables below to select the RediHeat model that meets the required GPM of hot water at the desired temperature.Note: Supply pressures above 15 psig must be reduced through a pressure regulator (“H” Package).

Single Wall

Desired Outlet Temp (ºF)

Winter Conditions40ºF Inlet Water

Hot Water Output (GPM)

Summer Conditions60ºF Inlet Water

Hot Water Output (GPM)Pressure 10 15 20 25 30+ 10 15 20 25 30+

110

RH-30 30 30 30 32 35 30 30 30 40 40RH-60 60 60 60 65 70 60 60 60 75 80RH-90 90 90 90 90 90 90 90 90 90 90

RH-120 120 120 120 120 120 120 120 120 120 120

120

RH-30 30 30 30 30 35 30 30 30 35 40RH-60 60 60 60 60 65 60 60 60 75 80RH-90 90 90 90 90 90 90 90 90 90 90

RH-120 120 120 120 120 120 120 120 120 120 120

140

RH-30 25 25 25 30 30 25 30 30 30 35RH-60 60 60 60 60 60 60 60 60 60 70RH-90 90 90 90 90 90 90 90 90 90 90

RH-120 115 120 120 120 120 120 120 120 120 120

150

RH-30 20 25 25 25 30 25 25 30 30 30RH-60 55 55 55 55 55 55 60 60 60 65RH-90 80 80 80 80 80 85 90 90 90 90

RH-120 110 110 110 110 110 115 115 115 115 120

160

RH-30 10 15 20 25 25 15 15 20 30 30RH-60 45 45 45 50 50 50 55 55 55 60RH-90 65 70 70 70 70 75 85 85 85 85

RH-120 90 90 90 90 95 105 110 110 110 115

Capacities are based on water pressure ranges of 30 to 150 psig. Presence of residual superheat following pressure reduction on steam supply pressures greater than 15 psig can increase capacity as shown. Inlet steam pressure above 50 psig (RH-90 & RH-120) and 75 psig (RH-30 & RH-60) require the installation of a safety relief valve.Units utilizing alternate tube materials will exhibit lower maximum capacities. To determine actual capacity, multiply the above values as follows: Admiralty - 0.95, Cupro Nickel - 0.81, Stainless Steel - 0.85

Double Wall

Desired Outlet Temp (ºF)

Winter Conditions40ºF Inlet Water

Hot Water Output (GPM)

Summer Conditions60ºF Inlet Water

Hot Water Output (GPM)Pressure 10 15 20 25 30+ 10 15 20 25 30+

110RH-30D 30 30 30 30 30 30 30 30 30 30RH-60D 60 60 60 60 60 60 60 60 60 60

120RH-30D 30 30 30 30 30 30 30 30 30 30RH-60D 60 60 60 60 60 60 60 60 60 60

140RH-30D 25 25 25 25 25 25 30 30 30 30RH-60D 60 60 60 60 60 60 60 60 60 60

160RH-30D 10 15 20 20 20 15 15 20 20 20RH-60D 45 45 45 45 45 50 55 55 55 60

Capacities are based on water pressure ranges of 30 to 150 psig. Inlet steam pressure above 50 PSIG (RH-90 & RH-120) and 75 psig (RH-30 & RH-60) requires the installation of a safety relief valve. Double wall units are available only with copper tubes

Engi

neer

ed

Prod

ucts

9:537

TI-12-007-US 3.13

Spirax Sarco, Inc., 1150 Northpoint Blvd, Blythewood, SC 29016 Telephone: (803) 714-2000 FAX (803) 714-2222

Sizing RediHeat "H" Package Pressure Regulator

When steam supply pressure to the RediHeat unit exceeds 15 psig the “H” Package must be furnished with the base unit. The “H” Package consists of 1 pressure reducing valve complete with pressure pilot and 1 strainer.

1. Determine the flow of steam in lbs/hr required to meet the unit’s capacity.2. Enter chart below at supply steam pressure and continue to move across until the required capacity in lbs/hr is found. From that point move

vertically and read the valve size indicated.

Example: RH-30 to heat 20 GPM water from 40-120ºF. Supply steam pressure is 100 psig.

Formula: GPM x 500 x ΔT (ºF) = lbs/hr946

20 x 500 x 80 = 846 lbs/hr946

In this example with a 100 psig steam supply pressure, a 3/4" pressure regulator will be suitable for the required duty of 846 lbs/hr of steam.

Steam Supply

Pressure (psig)

Pressure Regulator Selection ChartCapacity (lbs/hr) by valve size

1/2” 3/4” 1” 1-1/4” 1-1/2” 2” 2-1/2” 3” 4”

25 145 270 435 580 830 1,450 2,325 3,070 4,770

30 220 410 665 890 1,270 2,220 3,555 4,700 7,300

40 280 525 850 1,135 1,620 2,835 4,535 5,995 9,315

50 350 650 1,050 1,400 2,000 3,500 5,600 7,400 11,500

60 385 720 1,165 1,555 2,220 3,885 6,215 8,215 12,765

75 470 875 1,415 1,890 2,700 4,725 7,560 9,990 15,525

85 515 960 1,555 2,070 2,960 5,180 8,290 10,950 17,020

100 600 1,120 1,815 2,420 3,460 6,055 9,690 12,800 19,895

125 730 1,365 2,200 2,940 4,200 7,350 11,760 15,540 24,150

150 860 1,600 2,590 3,460 4,940 8,645 13,830 18,280 28,400

175 985 1,840 2,970 3,960 5,660 9,900 15,850 20,950 32,545

200 1,125 2,100 3,390 4,520 6,460 11,300 18,000 23,900 37,145

225 1,250 2,340 3,780 5,000 7,200 12,600 20,160 26,640 41,400

250 1,385 2,590 4,180 5,570 7,960 13,930 22,300 29,450 45,800 Notes:Pressure regulators supplied are Cast Iron as standard.½” – 2” regulators are threaded NPT as standard.2½” – 4” regulators (for steam supply pressures up to 125 psig) are flanged ANSI 125 as standard.For 2½” – 4” regulators where the steam supply pressure is above 125 psig, consult Spirax Sarco for 150 ANSI flanged regulator pricing.