E-Tech WH-35, WH-55, WH-75, WH-100, WH-115 Instruction Manual

Instruction Manual

COMMERCIAL ELECTRIC AIR-TO-WATER HEAT PUMP WATER HEATER

MODELS WH-35 to WH-170

SERIES 100

INSTALLATION - OPERATION - SERVICE

MAINTENANCE - LIMITED WARRANTY

820 SW 41st Street
Renton, WA 98057

Read and understand this instruction
manual and the safety messages
herein before installing, operating or
servicing this water heater.

Failure to follow these instructions and
safety messages could result in death
or serious injury.

This manual must remain with the
water heater.

FOR INDOOR INSTALLATION ONLY

PLACE THESE INSTRUCTIONS ADJACENT TO HEAT PUMP AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

PRINTED 0114 329360-000

TABLE OF CONTENTS

TABLE OF CONTENTS .......................................................................... 3

SAFE INSTALLATION, USE AND SERVICE.......................................... 4

GENERAL SAFETY INFORMATION ...................................................... 5

Precautions ........................................................................................ 5

Grounding Instructions ...................................................................... 5

INTRODUCTION .................................................................................... 6

Qualications ..................................................................................... 6

Preparing For The Installation ...........................................................6

Principle Of Operation .......................................................................7

The Refrigeration Cycle .............................................................. 7

Air Temperature Range...................................................................... 7

Water Temperature Range ................................................................ 7

Refrigerant Charge ............................................................................ 7

Equipment Disposal ........................................................................... 7

FEATURES AND COMPONENTS ......................................................... 8

Product Illustrations ........................................................................... 8

Rough In Dimensions ........................................................................9

Performance Specications ............................................................... 9

INSTALLATION REQUIREMENTS ...................................................... 10

Water Temperature .......................................................................... 10

Maximum System Temperature ................................................ 10

Inlet & Outlet Water Temperature .............................................. 10

Air Temperature ............................................................................... 10

Entering Air Temperature .......................................................... 10

Locating The Water Heater .............................................................. 10

Indoor Installation Only ............................................................. 10

Freezing Temperatures ............................................................. 10

Coastal Regions ........................................................................ 10

Heat Source .............................................................................. 10

Conditioned Space .................................................................... 10

Unconditioned Space .................................................................11

Clearances .......................................................................................11

Electrical Requirements ....................................................................11

Voltage & Amperage Ratings .....................................................11

Minimum Circuit Ampacity & Maximum Fuse Size .................... 12

Minimum Wire Size ................................................................... 12

Water Piping .................................................................................... 13

Maximum Pipe Length .............................................................. 13

Minimum Pipe Size ................................................................... 13

Pipe Support ............................................................................. 13

Pipe Insulation ........................................................................... 13

Cold Water Supply .................................................................... 13

Water Pressure ................................................................................ 13

Closed Water Systems .................................................................... 13

Thermal Expansion .......................................................................... 13

Mixing Valves ................................................................................... 13

Condensate Removal ...................................................................... 14

Contaminated Water ........................................................................ 14

Temperature - Pressure Relief Valve ............................................... 14

Tank Selection ................................................................................. 14

Contaminated Air ............................................................................. 14

Storage & Handling ......................................................................... 15

INSTALLATION .................................................................................... 16

Required Tools and Materials .......................................................... 16

Installation & Start Up Tools ...................................................... 16

Service Tools ............................................................................. 16

Unit Placement ................................................................................16

Ceiling Suspension ................................................................... 16

Pad Mounting ............................................................................ 16

Electrical Connections ..................................................................... 17

Correct Voltage And Phase ....................................................... 17

Branch Circuit Disconnect Switch ............................................. 17

Transformer Conguration 208 VAC Models ............................. 17

Water Connections .......................................................................... 17

Installation Instructions ............................................................. 17

Single Tank Conguration ................................................................ 18

Two Tank Pre Heat Conguration .................................................... 18

Condensate Drain Line .................................................................... 18

Standard Tank Thermostat .............................................................. 18

Digital Tank Thermostat Installation ................................................. 19

Temperature Sensor Installation ...................................................... 19

Air Flow and Ducting ....................................................................... 19

Duct Sizing ................................................................................ 19

Duct Insulation .......................................................................... 19

Make Duct Connections ............................................................ 19

Building Air Pressure ................................................................. 19

When To Install Ducting ............................................................ 20

Supply Air Ducting ..................................................................... 20

Return Air Ducting ..................................................................... 20

Blower Assembly Adjustments ......................................................... 20

INSTALLATION CHECKLIST ...............................................................22

START UP ............................................................................................23

Digital Tank Thermostat ................................................................... 24

MAINTENANCE AND SERVICE .......................................................... 25

Routine Maintenance ....................................................................... 25

TROUBLESHOOTING ......................................................................... 27

Checking Refrigerant Charge .......................................................... 28

Subcooling Calculation .............................................................. 28

Superheat Calculation ............................................................... 28

CONTROL SYSTEM ............................................................................ 29

Control Board ............................................................................ 29

Pressure Switches .................................................................... 29

Phase Monitor ........................................................................... 30

Compressor Overload Module .................................................. 30

Delay Timers ............................................................................. 30

How To Reset The Control System ........................................... 30

WIRING DIAGRAMS ............................................................................ 31

Thermostat And Accessory Wiring Diagrams .................................. 37

Digital Tank Thermostat Wiring ................................................. 37

Standard Tank Thermostat Wiring ............................................. 38

High Ambient Air Kit Wiring ....................................................... 39

Building Recirculation Pump Wiring Diagram ........................... 40

PIPING DIAGRAMS ............................................................................. 41

LIMITED WARRANTY .......................................................................... 47

3

SAFE INSTALLATION, USE AND SERVICE

The proper installation, use and servicing of this commercial heat pump water heater is extremely important to your safety and the
safety of others.

Many safety-related messages and instructions have been provided in this manual and on your own heat pump water heater to warn
you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very
important that the meaning of each safety message is understood by you and others who install, use, or service this heat pump water
heater.

This is the safety alert symbol. It is used to alert you to
potential personal injury hazards. Obey all safety
messages that follow this symbol to avoid possible
injury or death.

DANGER indicates an imminently

DANGER

WARNING

CAUTION

hazardous situation which, if not avoided,
will result in injury or death.

WARNING indicates a potentially hazardous
situation which, if not avoided, could result
in injury or death.

CAUTION indicates a potentially hazardous
situation which, if not avoided, could result in
minor or moderate injury.

CAUTION used without the safety alert

CAUTION

All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message, and
how to avoid the risk of injury.

The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances
known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of
potential exposure to such substances.

This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm. This
appliance can cause low level exposure to some of the substances listed in the Act.

symbol indicates a potentially hazardous
situation which, if not avoided, could result in
property damage.

APPROVALS

4

GENERAL SAFETY INFORMATION

PRECAUTIONS

DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN
UNDER WATER. Immediately call a qualied service agency to
inspect the appliance and to make a determination on what steps
should be taken next.

If the unit is exposed to the following, do not operate heater
until all corrective steps have been made by a qualied service
agency.

1. External re.

2. Damage.

3. Running without water.

When servicing this unit, verify the power to the unit is turned off prior to opening the control cabinet door.

CONTAINS REFRIGERANT!

System contains oil and refrigerant under high pressure. Recover
refrigerant to relieve pressure before opening the system. See unit
rating label for refrigerant type. Do not use non-approved refrigerants,
refrigerant substitutes, or refrigerant additives.

Failure to follow proper procedures or the use of non-approved
refrigerants, refrigerant substitutes, or refrigerant additives could
result in death or serious injury or equipment damage.

GROUNDING INSTRUCTIONS

This heat pump water heater must be grounded in accordance
with the National Electrical Code and/or local codes. These must
be followed in all cases. Failure to ground this water heater
properly may also cause erratic control system operation.

This heat pump water heater must be connected to a grounded
metal, permanent wiring system; or an equipment grounding
conductor must be run with the circuit conductors and connected
to the equipment grounding terminal or lead on the water heater.

Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.

Children, the elderly and the
physically or mentally disabled are at
highest risk for scald injury.

Feel water before bathing or
showering.

Temperature limiting devices such as
mixing valves must be installed
when required by codes and to
ensure safe temperatures at fixtures.

Explosion Hazard

Do not use oxygen to purge or
pressurize system for leak test.

Oxygen reacts violently with oil,
which can cause an explosion
resulting in severe personal
injury or death.

Electrical Shock Hazard

Turn off power to the water heater

•

before performing any service.

Label all wires prior to disconnecting

•

when performing service. Wiring errors
can cause improper and dangerous
operation.

Verify proper operation after servicing.

•

Failure to follow these instructions can

•

result in personal injury or death.

Read and understand this instruction
manual and the safety messages
herein before installing, operating or
servicing this water heater.

Failure to follow these instructions and
safety messages could result in death
or serious injury.

This manual must remain with the
water heater.

Explosion Hazard

Overheated water can cause
water tank explosion.

Properly sized temperature and
pressure relief valve must be
installed in the opening provided
on connected storage tanks.

5

INTRODUCTION

Thank You for purchasing this heat pump water heater. Properly
installed and maintained, it should give you years of trouble free
service.

Abbreviations found In this Instruction Manual include:

• HPWH - Heat Pump Water Heater

• ANSI - American National Standards Institute

• ASME - American Society of Mechanical Engineers

• NEC - National Electrical Code

• NFPA - National Fire Protection Association

• AHRI - Air-conditioning, Heating and Refrigeration Institute

QUALIFICATIONS

QUALIFIED INSTALLER OR SERVICE AGENCY:

Installation and service of this water heater requires ability
equivalent to that of a Qualied Agency (as dened by ANSI
below) in the eld involved. Installation skills such as plumbing,
electrical supply are required in addition to electrical testing skills
when performing service.

This heat pump water heater contains R-134a refrigerant and is
regulated as a stationary refrigeration appliance under Section
608 of the Clean Air Act. Servicing of the refrigeration circuit must
only be performed by agencies or individuals possessing Type II
or Universal certication as dened in Section 608 of the Clean
Air Act.

ANSI Z223.1 2006 Sec. 3.3.83: “Qualied Agency” - “Any
individual, rm, corporation or company that either in person or
through a representative is engaged in and is responsible for (a)
the installation, testing or replacement of gas piping or (b) the
connection, installation, testing, repair or servicing of appliances
and equipment; that is experienced in such work; that is familiar
with all precautions required; and that has complied with all the
requirements of the authority having jurisdiction.”

PREPARING FOR THE INSTALLATION

Read and understand this instruction
manual and the safety messages
herein before installing, operating or
servicing this water heater.

Failure to follow these instructions and
safety messages could result in death
or serious injury.

This manual must remain with the
water heater.

1. Read the “General Safety Information” section of this manual
rst and then the entire manual carefully. If you don’t follow
the safety rules, the heat pump water heater may not operate
safely. It could cause DEATH, SERIOUS BODILY INJURY
AND/OR PROPERTY DAMAGE.

This manual contains instructions for the installation,
operation, and maintenance of the heat pump water heater
(HPWH). It also contains warnings throughout the manual
that you must read and be aware of. All warnings and all
instructions are essential to the proper operation of the
HPWH and your safety. READ THE ENTIRE MANUAL

BEFORE ATTEMPTING TO INSTALL OR OPERATE THIS
WATER HEATING APPLIANCE.

Detailed installation diagrams are in this manual. These
diagrams will serve to provide the installer with a reference
for the materials and suggested methods of piping. IT
IS NECESSARY THAT ALL WATER PIPING AND THE
ELECTRICAL WIRING BE INSTALLED AND CONNECTED
AS SHOWN IN THE DIAGRAMS.

Particular attention should be given to the installation of the
system (tank) temperature control. See page 19.

Electrical Shock Hazard

Turn off power to the water heater

•

before performing any service.

Label all wires prior to disconnecting

•

when performing service. Wiring errors
can cause improper and dangerous
operation.

Verify proper operation after servicing.

•

Failure to follow these instructions can

•

result in personal injury or death.

Be sure to turn off power when working on or near the
electrical system of the heat pump. Never touch electrical
components with wet hands or when standing in water.

When replacing fuses always use the correct size for the
circuit. See Unit Wiring Diagrams-Fuse Sizes, pages 32-36.

The principal components of the HPWH are identied in the
Features And Components section of this manual on page

8. The rating label on the HPWH also provides useful
information. These references should be used to identify the
heat pump, its components and optional equipment.

2. The installation must conform with these instructions and the
local code authority having jurisdiction and the requirements
of the power company. In the absence of local codes, the
installation must comply with the latest editions of the
National Electrical Code, ANSI/NFPA 70 or the Canadian
Electrical Code CSA C22.1. The National Electrical Code
may be ordered from: National Fire Protection Association,
1 Batterymarch Park, Quincy, MA 02269. The Canadian
Electrical Code is available from the Canadian Standards
Association, 8501 East Pleasant Valley Road, Cleveland,
OH 44131.

3. If after reading this manual you have any questions or do not
understand any portion of the instructions DO NOT proceed
with the installation. Call the toll free number listed on the
back cover of this manual for technical assistance.

4. In order to expedite your request, please have full model and
serial number available for the technician.

5. Carefully consider your intended placement and location for
the HPWH. See Locating The Water Heater on page 10

6. Installation and service of this HPWH requires ability
equivalent to that of a licensed tradesman or Qualied Agency
in the eld involved. See Qualications on page 6.

7. For installation in California the HPWH appliance must be
braced or anchored to avoid falling or moving during an
earthquake. Instructions may be obtained from California
Ofce of the State Architect, 1102 Q Street, Suite 5100,
Sacramento, CA 95811.

6

8. Ensure the power supply voltage and phase at the job site
matches the power requirements on the HPWH rating label
before installation begins. Energizing the HPWH with the
wrong voltage or phase will cause permanent damage to the
unit.

PRINCIPLE OF OPERATION

The appliances covered by this Instruction Manual are
commercial air-to-water heat pump water heaters (HPWH).

Operation of the HPWH is similar to that of a package air
conditioning system though the HPWH is designed for indoor
installation only. The primary difference in operation is that
the HPWH unit utilizes the heat removed from the conditioned
space to heat water where package air conditioning systems
discard this heat outdoors. Recovering and using this waste heat
increases the overall energy efciency of the building.

THE REFRIGERATION CYCLE

Refer to Figure 1 on page 8 for the location of components
mentioned in this section.

Refrigerant is circulated through the refrigeration circuit by a
Compressor (1). The refrigerant is a high temperature high
pressure gas when it leaves the compressor. Refrigerant
ows from the compressor through the Hot Gas Line (2) to the
Condenser (3).

The condenser is a refrigerant-to-water heat exchanger with two
circuits, refrigerant ows through one circuit and water through
the other. The high temperature refrigerant gas transfers its heat
to the water owing through the condenser. As the refrigerant
gas cools inside the condenser it changes state (condenses)
from a gas to a liquid. A Water Pump (B) circulates water through
the condenser.

Refrigerant leaving the condenser is a medium temperature
high pressure liquid. It ows through the Liquid Line (4) to the
Thermostatic Expansion Valve (5). The thermostatic expansion
valve (TXV) regulates the ow of refrigerant into the Evaporator
(6). The evaporator is a tube-and-n constructed coil. It is an air­to-refrigerant heat exchanger with refrigerant owing through the
tubes and air owing across the ns.

The Blower moves ambient air from the installed space or air
ducted to the HPWH from another location across the ns of
evaporator coil. The refrigerant absorbs heat from the air in the
evaporator. The refrigerant changes state (boils/evaporates)
from a liquid state back into a gas (vapor) in the evaporator.

The refrigerant ows out of the evaporator through the Suction
Line (7) and into the Accumulator (8). The accumulator traps any
liquid refrigerant the evaporator is unable to vaporize during low
temperature operating conditions. The accumulator prevents
liquid refrigerant from entering the compressor where it could
damage internal components.

Low temperature low pressure refrigerant gas (vapor) is drawn
out of the accumulator by the compressor. The compressor
increases the pressure and temperature of the refrigerant gas
circulating it to the condenser again where the refrigeration cycle
starts over or continues.

AIR TEMPERATURE RANGE

The entering air temperature operating range for the HPWH is
50°F to 95°F (10°C to 35°C).

When the HPWH is operating properly the air temperature drop
through the evaporator (heat exchanger) will be approximately
12°F to 20°F (7°C to 11°C).

WATER TEMPERATURE RANGE

The inlet (entering) water temperature operating range for the
HPWH is 50°F to 140°F (10°C to 60°C).

When the HPWH is operating properly the water temperature rise
through the condenser (heat exchanger) will be approximately
8°F to 12°F (4°C to 7°C).

REFRIGERANT CHARGE

The HPWH is factory-charged with R-134a refrigerant. The
refrigerant charge is weighed in at the factory. See Table 9
on page 28. It should not be necessary to add or remove
refrigerant during installation or start up.

EQUIPMENT DISPOSAL

This heat pump water heater contains R-134a refrigerant and is
regulated as a stationary refrigeration appliance under Section
608 of the Clean Air Act. Disposal of this unit must be performed
in accordance with the provisions in Section 608 of the Clean Air
Act and any state or local regulations that may also apply. See
Qualications on page 6.

7

PRODUCT ILLUSTRATIONS

COMPRESSOR

CONTROL

PANEL

WATER

PUMP

FEATURES AND COMPONENTS

ACCUMULATOR

THERMOSTATIC

EXPANSION VALVE (TXV)

EVAPORATOR COIL

(HEAT EXCHANGER)

(AIR TO REFRIGERANT)

BLOWER

MOTOR

RETURN AIR

INLET

(AIR FILTERS)

CONDENSER

(HEAT EXCHANGER)

(REFRIGERANT TO WATER)

SUPPLY AIR

OUTLET

WARM RETURN

AIR IN

COOL SUPPLY

AIR OUT

CONDENSATE

BLOWER

COMPONENT REFRIGERATION CIRCUIT

1) COMPRESSOR

2) HOT GAS LINE

3) CONDENSER / HEAT EXCHANGER

4) LIQUID LINE

5) THERMOSTATIC EXPANSION VALVE (TXV)

6) EVAPORATOR

7) SUCTION LINE

8) ACCUMULATOR

COMPONENT WATER CIRCUIT

A) WATER INLET

B) WATER PUMP

C) HEAT EXCHANGER / CONDENSER

D) WATER OUTLET

DRAIN

REFRIGERANT STATE

GAS

GAS

GAS TO LIQUID

LIQUID

LIQUID

LIQUID TO GAS

GAS

GAS / LIQUID

Figure 1

8

ROUGH IN DIMENSIONS

Figure 2

PERFORMANCE SPECIFICATIONS

TABLE 1

PERFORMANCE

MODEL

NUMBER

WH-35 10.4 35,500 27,500 2.3 3.9 1040 7 1.0” 40” 26” 24.75” 7" 315

WH-55 17.0 58,000 45,500 3.8 4.1 1650 11 1.0” 47” 32” 28.5” 7" 405

WH-75 22.3 76,000 59,000 4.9 3.9 2150 15 1.5” 57” 32” 28.5” 7" 485

WH-100 28.7 98,000 78,000 6.5 4.2 3200 20 1.5” 63” 38” 42.5” 8" 660

WH-115 33.1 113,000 89,000 7.4 4.2 3200 23 1.5” 63” 38” 42.5” 8" 665

WH-140 41.6 142,000 110,000 9.2 3.9 3800 28 2.0” 63” 38” 42.5” 8" 725

WH-170 50.1 171,000 133,000 11.1 3.9 4900 34 2.0” 75” 46” 42.5” 8" 880

All dimensions are in inches. Weights are approximate shipping weights.

*Performance rating at 75ºF Entering Air Temperature and 55% Relative Humidity, 100ºF Entering Water Temperature.

** Blower design at 0.35” external static pressure.

All models standard 208/230 VAC, 3Ø, 60 Hz

Optional 460 VAC, 3Ø, 60 Hz

Optional 208/230 VAC, 1Ø, 60 Hz available on AWH-35 and AWH-55 only

WATER

HEATING

CAPACITY

kW Btu/hr* Btu/hr Tons

COOLING

CAPACITY

COP

AIR

VOLUME

(CFM)

WATER

FLOW
(GPM)

INLET

OUTLET

WATER

(FPT)

DIMENSIONS

WIDTHADEPTHBHEIGHT

C

D

WEIGHT

(LBS)

9

INSTALLATION REQUIREMENTS

CAUTION

Read all installation requirements in this manual before installation
begins. The installation must conform to these instructions and
all local and national code authority having jurisdiction.

Costs to diagnose, perform service and repair damage caused
by installation errors are not covered under the limited warranty.

Costs to correct installation errors are not covered under the
limited warranty.

WATER TEMPERATURE

MAXIMUM SYSTEM TEMPERATURE

The HPWH units covered in this manual are capable of
maintaining a maximum system/storage tank temperature of
140°F (60°C). Some commercial water heating applications
may require higher temperatures. Install a booster water heater
downstream from the storage tank for temperatures above
140°F (60°C). See Figure 8 on page 18.

INLET & OUTLET WATER TEMPERATURE

The inlet (entering) water temperature operating range for the
HPWH is 50°F to 140°F (10°C to 60°C). The water temperature
rise (Delta T - ∆T) through the condenser (heat exchanger) will
be approximately 8°F to 12°F (4°C to 7°C).

Outlet water temperatures up to 152°F (67°C) are possible
during normal operation. Exposure to water temperatures this
high can cause serious bodily injury or death. See Mixing Valves
and Table 5 on page 14.

Service & Installation Notes:

If the inlet (entering) water temperature is outside the operating
temperature range for extended periods the control system may
lock out on high or low refrigerant pressure switch events/trips.

When the control system locks out on a refrigerant pressure
switch event the compressor will stop running, the blower and
circulation pump (on models equipped with factory installed
pump) will continue to operate. This is a hard lock out condition.
The control system is manually reset by cycling power to the
HPWH off and then on again.

The tank thermostat must not be set any higher than 140°F
(60°C) to prevent control system lock outs.

Ground water temperatures can fall below 50°F (10°C) for
extended periods during winter months in many regions. For this
reason the cold water supply lines and should not be connected
directly to the HPWH inlet or T tted into the inlet (return) water
piping. The cold water supply lines should be connected directly
to the storage tank only. See the Piping Diagrams on page 41
in this manual for more information.

AIR TEMPERATURE

ENTERING AIR TEMPERATURE

The return (entering) air temperature range of operation for
the unit is 50° - 95°F (10°C to 35°C). The air temperature drop
(Delta T - ∆T) through the evaporator (heat exchanger) will be
approximately 12°F to 20°F (7°C to 11°C).

If the entering air temperature is outside this operating range
the HPWH unit’s Ambient Air Limit Thermostat will discontinue
heating operation until the entering air temperature returns to this
operating range. See Figure 15 on page 37.

High Ambient Air Kits are available that will allow the unit to
operate with entering air temperatures up to 120°F (49°C). These
accessory kits must be installed if entering air temperatures
exceed 95°F (35°C) for extended periods.

Contact your local distributor or call the technical support
phone number listed on the back cover of this manual for more
information on ordering one of these accessory kits.

Service & Installation Notes:

When the High Ambient Air kit is installed the heating stage set
point on the Ambient Air Limit thermostat must be raised to 120°F
(49°C) to allow heating operation up to this temperature.

LOCATING THE WATER HEATER

PROPERTY DAMAGE!

All water heaters eventually leak.

•

Do not install without adequate drainage.

•

INDOOR INSTALLATION ONLY

The HPWH unit is designed for indoor installation only.

Carefully choose a location for the HPWH unit. Placement is a
very important consideration for optimal performance and safety.

Locate the HPWH near a oor drain. The unit should be located
in an area where leakage from the HPWH unit or the storage tank
it is connected to will not result in damage to the area adjacent
to the water heater or to lower oors of the structure. See Unit
Placement on page 16.

FREEZING TEMPERATURES

The HPWH unit must not be installed in space where freezing
temperatures will occur. Exposure to freezing ambient
temperatures below 32°F (0°C) may result in severe damage to
internal components. Damage caused by exposure to freezing
temperatures is not covered under the limited warranty.

COASTAL REGIONS

When the HPWH will be installed within 5 miles of a seacoast the
optional Corrosive Duty Package is required. The corrosive duty
package includes a 316 stainless steel cabinet and a phenolic
coating applied to the evaporator and blower. Damage caused to
units not equipped with the corrosive duty package in coastal
regions is not covered under the limited warranty.

HEAT SOURCE

The HPWH unit should be located where there is an adequate
source of ambient heat and where the cooling benet can be
utilized when possible.

If installation in a space with an adequate heat source is not
possible the HPWH unit can be ducted to/from another space
such as a boiler room or to the outdoors where sufcient heat is
available. See Air Flow and Ducting on page 19.

CONDITIONED SPACE

When installed in a conditioned space ducting supply (outlet) air
to an alternate location may be necessary to avoid over-cooling
of the space where the HPWH is installed or provide spot cooling
in areas for comfort and/or to offset cooling load. See Building Air
Pressure, Air Flow and Ducting on page 19.

10

UNCONDITIONED SPACE

When installed in an unconditioned space ducting return (inlet)
air from an alternate location may be necessary to access an

Building Air Pressure, Air Flow and Ducting on page 19.

CLEARANCES

To ensure optimal performance a minimum of 30 inches clearance
is required from the back, left and right sides of the HPWH unit
and any wall obstruction. A minimum of 36 inches clearance on
the front of the unit for access to the control box. See Figure 3

When installed on an equipment pad the HPWH must be level

permit connection of the condensate line and trap.

ELECTRICAL REQUIREMENTS

CAUTION

CORRECT POWER SUPPLY!

Ensure the power supply at the job site matches the

•

voltage and phase listed on the HPWH rating label
before connecting power to the HPWH unit.

Energizing the HPWH with the wrong voltage or phase

•

will cause permanent damage to the HPWH unit.

Damage caused to the HPWH as the result of applying

•

the wrong voltage or phase is not covered under the
limited warranty.

Ensure the power supply voltage and phase at the job site
matches the power supply ratings listed on the HPWH rating
label BEFORE INSTALLATION BEGINS.

The installation must conform with these instructions and the
local code authority having jurisdiction and the requirements
of the power company. In the absence of local codes, the
installation must comply with the current editions of the National
Electrical Code, ANSI/NFPA 70 or the Canadian Electrical Code
CSA C22.1.

Voltage applied to the HPWH should not vary more than +5% to

-10% of the voltage requirement listed on the HPWH rating label
for satisfactory operation.

VOLTAGE & AMPERAGE RATINGS

Figure 3

TABLE 2

MODEL VOLTS/PHASE/HZ

WH-35 208-230/1/60 18.60 100.00 29.00 3.60 1/2 0.88 1/8 28 45

WH- 35 208-230/3/60 10.90 77.00 17.00 2.40 1/2 0.88 1/8 17 25

WH- 35 460/3/60 5.40 39.00 8.50 1.20 1/2 0.88 1/8 9 12

WH-55 208-230/1/60 27.90 175.00 43.50 5.30 3/4 0.88 1/8 42 60

WH-55 208-230/3/60 19.90 115.00 31.00 3.00 3/4 0.88 1/8 29 45

WH-55 460/3/60 8.70 63.00 13.50 1.50 3/4 0.88 1/8 13 20

WH-75 208-230/3/60 24.00 196.00 37.50 3.60 1 0.88 1/8 35 50

WH-75 460/3/60 11.50 100.00 18.00 1.80 1 0.88 1/8 17 25

WH-100 208-230/3/60 28.20 225.00 44.00 3.60 1 0.88 1/8 40 60

WH-100 460/3/60 14.10 114.00 22.00 1.80 1 0.88 1/8 20 30

WH-115 208-230/3/60 35.30 239.00 55.00 3.60 1 1.00 1/6 49 80

WH-115 460/3/60 17.90 125.00 28.00 1.80 1 1.00 1/6 25 40

WH-140 208-230/3/60 48.10 300.00 75.00 4.80 1 1/2 2.50 1/2 68 110

WH-140 460/3/60 21.80 150.00 34.00 2.40 1 1/2 2.50 1/2 31 50

WH-170 208-230/3/60 52.60 340.00 82.00 6.20 2 2.50 1/2 75 125

WH-170 460/3/60 25.60 173.00 40.00 3.10 2 2.50 1/2 37 60

*460 VAC models factory-equipped with step down transformer for 230 VAC pump

Abbreviations:

RLA = Running Load Amps; LRA = Locked Rotor Amps; MCC = Maximum Continuous Current;

FLA = Full Load Amps; MCA = Minimum Circuit Ampacity; MFS = Maximum Fuse Size

COMPRESSOR BLOWER MOTOR PUMP (230 VAC 1Ø)*

RLA LRA MCC FLA HP FLA HP

MCA MFS

11

MINIMUM CIRCUIT AMPACITY & MAXIMUM FUSE SIZE

Table 2 on page 11 provides the MCA (Minimum Circuit
Ampacity) and MFS (Maximum Fuse Size). Use MCA to select
the minimum eld wires size to power the unit and MFS to select
the maximum fuse size for over current protection as follows:

Electrical Shock Hazard

Before removing any access panels or

•

servicing the water heater, make sure
the electrical supply to the water heater
is turned “OFF.”

Failure to do this could result in death,

•

serious bodily injury, or property
damage.

MINIMUM WIRE SIZE

Allowable Ampacities of Insulated Conductors

Single-phase heat pump water heaters are two wire circuits. Three-phase heaters are three wire circuits. In addition to the foregoing,
a grounded conductor is required. Not more than three conductors in raceway, cable, or earth (directly buried), based on ambient
temperature of 30°C (86°F)

TABLE 3

MCA = C x 1.25 + M + P

MFS = C x 2.25 + M + P

Where:

C - Compressor RLA

M - Blower Motor FLA

P - Pump FLA

+The load current rating and the overcurrent protection for these conductors shall not exceed 15 amperes for 14 AWG. 20 amperes for 12 AWG and 30 amperes for
10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum.

*For dry locations only. See 75°C column for wet locations.

12

WATER PIPING

CLOSED WATER SYSTEMS

Read all installation requirements in this manual before
installation begins.

The water piping installation must conform to these instructions
and to all local and national code authority having jurisdiction.

Costs to diagnose, perform service and repair damage caused
by installation errors are not covered under the limited warranty.

Costs to correct installation errors are not covered under the
limited warranty.

MAXIMUM PIPE LENGTH

up to a total of 50 equivalent feet of water piping between the
HPWH and the storage tank. Example: 25 equivalent feet of inlet
(return) piping and 25 equivalent feet of outlet (supply) piping.

Exceeding these maximum lengths will cause the unit to
malfunction and control system lock outs.

MINIMUM PIPE SIZE

The inlet (return) and outlet (supply) water piping installed
between the HPWH unit and the storage tank must not be smaller
than the water connection sizes on the HPWH. See Table 4 for

Water line sizing is a critical installation requirement. Installing
undersized water piping between the storage tank and the

adverse impact on performance and equipment life.

TABLE 4

WATER CONNECTIONS AND FLOW

UNIT GPM LPM CONNECTION SIZE (INCH)

WH-35 7 27 1

WH-55 11 42 1

WH-75 15 57 1.5

WH-100 20 76 1.5

WH-115 23 87 1.5

WH-140 28 106 2

WH-170 34 129 2

PIPE SUPPORT

All water piping must be properly supported per local code
requirements.

PIPE INSULATION

All piping installed between the HPWH unit and the storage tank
must be insulated.

COLD WATER SUPPLY

Cold water supply lines should not be connected directly to the

water supply lines should be connected directly to the storage
tank only. See Inlet & Outlet Water Temperature on page 10
and Figure 7 and Figure 8 on page 18.

WATER PRESSURE

System water pressure should be maintained between 40 and 60
PSI. Local code may require, and the manufacturer recommends,
installing a pressure reducing valve (PRV) in the cold water
supply to the building to maintain consistent water pressure.

Water supply systems may, because of code requirements
or such conditions as high line pressure, among others, have
installed devices such as pressure reducing valves, check

the water system to be a closed system.

THERMAL EXPANSION

As water is heated, it expands (thermal expansion). In a closed
system the volume of water will grow when it is heated. As the
volume of water grows there will be a corresponding increase
in water pressure due to thermal expansion. Thermal expansion
can cause premature failure (leakage) of storage tanks, water
heaters and HPWH components such as the condenser.
Leakage caused by thermal expansion is not covered under the
HPWH limited warranty.

Thermal expansion can also cause intermittent Temperature­Pressure Relief Valve operation: water discharged due to
excessive pressure build up. The Temperature-Pressure Relief
Valve is not intended for the constant relief of thermal expansion.

A properly sized thermal expansion tank must be installed on
all closed systems to control the harmful effects of thermal
expansion. Contact a local plumbing service agency to have a
thermal expansion tank installed on all closed water systems.

MIXING VALVES

Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.

Children, the elderly and the
physically or mentally disabled are at
highest risk for scald injury.

Feel water before bathing or
showering.

Temperature limiting devices such as
mixing valves must be installed
when required by codes and to
ensure safe temperatures at fixtures.

Water heated to a temperature which will satisfy clothes washing,
dish washing, and other sanitizing needs can scald and cause
permanent injury upon contact. See Table 5.

Some people are more likely to be permanently injured by hot

and the physically/mentally disabled. The Table below shows
the approximate time-to-burn relationship for normal adult skin.
If anyone using hot water provided by the water heater being

or state law requiring a certain water temperature at the point of
use, then special precautions must be taken.

In addition to using the lowest possible temperature setting that

taps to further reduce system water temperature.

Mixing valves are available at plumbing supply stores. Consult

manufacturer’s instructions for installation of the valves.

13

TABLE 5

Water Temperature

180°F (82°C) Nearly instantaneous

170°F (77°C) Nearly instantaneous

160°F (71°C) About 1/2 second

150°F (66°C) About 1-1/2 seconds

140°F (60°C) Less than 5 seconds

130°F (54°C) About 30 seconds

120°F (49°C) More than 5 minutes

Time to Produce 2nd & 3rd

Degree Burns on Adult Skin

CONDENSATE REMOVAL

The HPWH unit produces condensate which must be discharged.
If there is no drain easily accessible, a condensate lift pump must
be installed to discharge the condensate to a remote location. See
Condensate Drain Line on page 18 for installation instructions.

CONTAMINATED WATER

Corrosive Chemical Hazard

Connecting the heat pump to any system other than a water

•

system may lead to premature corrosion of the unit's heat
exchanger and void the unit warranty.

This HPWH unit must not be used to heat any uid other than
water. Corrosive chemicals must not be introduced into the
waterways in this HPWH unit.

TEMPERATURE - PRESSURE RELIEF VALVE

Explosion Hazard

Temperature-Pressure Relief Valve
must comply with ANSI Z21.22­CSA 4.4 and ASME code.

Properly sized temperature­pressure relief valve must be
installed in the designated
opening in the storage tank.

connected to the storage tank. If more than one water heating
appliance is connected to the storage tank the aggregate total
of all heating input ratings of all connected appliances must be
factored when choosing a T&P valve for the storage tank.

The pressure rating of the T&P valve should always be rated
equal to or below the working pressure rating of the storage tank
or water heater, whichever rating is lower.

Contact the manufacturer of the storage tank for assistance in
sizing of a temperature and pressure relief valve. Follow the
storage tank manufacturer’s instructions regarding the proper
installation of these products.

TANK SELECTION

The HPWH unit is not an instantaneous water heater and must
be connected to a storage tank. Storage tank congurations must
meet these criteria:

1. The HPWH must not be connected directly to a standard gas
or electric water heater.

2. If the HPWH is connected to a used storage tank, the tank
should be thoroughly cleaned of scale and sediment before
the HPWH is installed.

3. Connection ports used on the storage tank must permit the
recommended ow rate through HPWH. The connection
ports used on the storage tank must not be smaller than the
inlet outlet connection sizes on the HPWH unit. See Table 4
on page 13.

4. Water heated by the HPWH should be returned to the tank at
a location that is above the level of the tank’s cold water inlet
and/or the heat pump’s inlet source.

5. The HPWH unit’s inlet and outlet lines to the storage tank
should be dedicated. Example: no other line (such as a
building re-circulating loop or cold water supply) should be
connected to the HPWH unit’s inlet or outlet water lines.

SOLAR TANKS

Solar tanks should be used with caution. Some solar tanks with
top connections have dip tubes which may signicantly reduce
the efciency performance of the HPWH unit.

Before using any solar tank in this application, contact your
representative or call the toll free technical support number on
the back cover of this manual for further assistance.

CONTAMINATED AIR

Can result in overheating and
excessive tank pressure.

Can cause serious injury or death.

This heat pump water heater should only be connected to a
storage tank with a properly rated/sized and certied combination
temperature - pressure relief valve. The valve must be certied by
a nationally recognized testing laboratory that maintains periodic
inspection of production of listed equipment of materials as
meeting the requirements for Relief Valves for Hot Water Supply
Systems, ANSI Z21.22 • CSA 4.4, and the code requirements of
ASME.

When the HPWH unit is connected to a storage tank a temperature
and pressure relief valve must be installed in the designated
opening for the T&P valve per the storage tank manufacturer’s
requirements. The T&P valve’s Btu/hr rating must be equal to
or greater than the total heating input rating of all water heaters

Breathing Hazard - Carbon Monoxide Gas

Do not duct air from a garage or other
space where potentially harmful fumes
from solvents, chemicals or exhaust
from automobiles are present into any
other space in the building structure.

Gas and carbon monoxide detectors
are available.

Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.

The supply (outlet) air from a HPWH installed in a garage or a
unit drawing return (inlet) air from a garage or any area where
solvents or other chemicals that emit potentially harmful fumes
are stored or automobiles are located must never be ducted to
any other space inside the building structure. This would include
all occupied and unoccupied spaces such as attics or basements.

14

Potentially harmful fumes and vapors could be introduced into
occupied spaces. See Unit Placement on page 16.

STORAGE & HANDLING

HEAVY OBJECT!

All Heat Pump Water Heaters (HPWHs) covered by this manual
are beyond the safe lifting weight for one person. Use
proper conveyance equipment to move the unit for storage
or during installation. Use OSHA approved safety equipment
when moving the unit

The heat pump water heaters covered in this manual are
stationary refrigeration appliances. Careful handling is necessary
to prevent internal damage.

• IMPORTANT: Do not remove, cover or deface any
permanent instructions, wiring diagrams, labels, or the
rating label from the outside cabinet or the inside panels on
the HPWH unit.

• Do not tilt the unit beyond 45° at any time. All internal
components are braced from the base of unit. Tilting may
compromise the refrigeration piping inside unit and cause
refrigerant leaks.

• Do not hoist the unit with chains or straps unless
spreader bars are furnished and used as depicted in
Figure 4 and Figure 5. The side panels and roof of the
unit are not constructed to handle signicant force from
the sides or above.

• The HPWH unit is heaviest on the compressor side (left
side when facing the front of the unit). See Figure 4 and
Figure 6.

• When using a forklift to raise the HPWH unit ensure the
forks are positioned correctly between the runners on the
bottom of the HPWH unit. See Figure 6.

• The HPWH unit must be lifted from the front side only
when using a forklift to raise the unit. See Figure 6.

COMPRESSOR
SIDE

.

SPREADER

BAR

RIGGING

SPREADER

BAR

SIDE

Figure 5

Figure 6

STORAGE RECOMMENDATIONS

The HPWH units should be stored indoors. Do not stack units or
stack other construction materials on the units while in storage.

The HPWH units contain electrical/electronic components
and should only be stored in conditions between 0ºF to 110°F
(-17°C to 43°C) and 5 to 95 percent relative humidity. Electrical
components are not moisture-tolerant.

NOTE: The limited warranty does not cover damage to the unit or
controls due to negligence during storage.

FRONT

SUPPORT BARS

Figure 4

15

INSTALLATION

REQUIRED ABILITY

Installation and service of the HPWH unit requires ability
equivalent to that of a qualied agency in the eld involved.
Plumbing, ducting and electrical work are required. See
Qualications on page 6.

GENERAL

The installation must conform with these instructions and the
local code authority having jurisdiction. In the absence of local
codes, the installation must comply with the latest editions of
the National Electrical Code, ANSI/NFPA 70 or the Canadian
Electrical Code CSA C22.1. The National Electrical Code
may be ordered from: National Fire Protection Association, 1
Batterymarch Park, Quincy, MA 02269. The Canadian Electrical
Code is available from the Canadian Standards Association,
8501 East Pleasant Valley Road, Cleveland, OH 44131.

DO NOT start the HPWH unit or test the electrical system before
it is connected to the water system, purged of air and lled with
water. See Start Up on page 23.

See Features And Components on page 8 to identify the
principal components of the HPWH.

REQUIRED TOOLS AND MATERIALS

INSTALLATION & START UP TOOLS

1. All tools common to installation and service of commercial
electric water heaters such as hand tools, pipe cutter and
torch.

2. Heat transfer compound (paste) such as Honeywell part
number 107408 or equivalent.

3. Electrical switch lock out device - used to secure disconnect
switches/breaker panels while servicing.

4. Electronic thermometer including:

• Four (4) thermocouple sensors capable of measuring
surface temperatures on water or refrigerant piping up to
2 inch diameter.

• Two (2) thermocouple sensors capable of measuring
ambient air temperature.

• Temperature range 32°F - 210°F (0°C - 100°C).

5. Volt-Ohm Multi Meter - capable of measuring:

• AC Voltage up to 600 VAC.

• DC Voltage up to 24 VDC.

• Ohms up to 2,000,000 ohms.

• Continuity.

6. AC amp meter - capable of measuring:

• AC amperage up to 200 amps.

7. Calculator.

SERVICE TOOLS

See Qualications on page 6 regarding regulations and
certications required under Section 608 of the Clean Air Act
before servicing the refrigeration circuit.

1. Refrigeration manifold gauges.

2. Refrigeration charging scale.

3. Refrigeration vacuum pump.

4. Refrigerant recovery machine.

5. Refrigerant reclamation storage tank.

UNIT PLACEMENT

Whether replacing existing water heating equipment or installing
the HPWH in new construction, the following critical points must
be observed: The HPWH unit:

1. Must be installed indoors.

2. Should be installed near a oor drain for condensate removal.

3. The HPWH, storage tank and water heater(s) should be
located in an area where leakage will not result in damage
to adjacent area or to lower oors in the building structure.

4. The HPWH unit must be level for proper condensate
drainage. Shim the channel type skid base, pad or oor as
necessary if levelling is required.

5. Should be installed close to the point of major hot water
usage and power supply.

6. Should be located so that hot water piping and branch circuit
wiring will be as short as possible.

CEILING SUSPENSION

Because warm air rises, a drop ceiling or suspended from ceiling
conguration is preferred to take advantage of higher ambient
temperatures. The HPWH may be suspended from the ceiling
using a safe and properly designed support. The sides and top
of the cabinet are not designed to support the weight of the unit.
Do not attach straps or bars directly to the sides or top of the
cabinet. If the HPWH is suspended, it must be supported from
underneath.

Mounting Frame

The mounting frame must support the length, width, and weight
of the HPWH unit. The weight of the HPWH unit must be evenly
dispersed across the footing channels on the bottom of the unit.
See Table 1 on page 9 for unit dimensions and weights.

NOTE: A qualied engineer should design and size the structural
components of the mounting frame and the appropriate hangers.
Structural channels in a eld-provided frame should be mounted
perpendicular to the unit’s footing channels. The following critical
points must be observed when the HPWH unit is suspended
from the ceiling:

1. Hanging rods must not obstruct access doors.

2. VIBRATION ISOLATORS ARE REQUIRED to prevent
transmission of mechanical vibration into the building
structure. Selection of suitable isolators should be made by
a qualied engineer.

3. Installation must meet local seismic restraint requirements.

PAD MOUNTING

The HPWH may be pad mounted. Vibration isolator mounts
MUST BE placed between the unit and the equipment pad to
prevent mechanical vibration transmitting into the building
structure. Selection of appropriate vibration isolators should be
made by a qualied engineer. Unit must be level and elevated at
least 6” above oor to avoid dust and debris from entering the unit
and permit connection of the condensate trap. See Condensate
Drain Line on page 18.

16

ELECTRICAL CONNECTIONS

CAUTION

CORRECT POWER SUPPLY!

Ensure the power supply at the job site matches the

•

voltage and phase listed on the HPWH rating label
before connecting power to the HPWH unit.

Energizing the HPWH with the wrong voltage or phase

•

will cause permanent damage to the HPWH unit.

Damage caused to the HPWH as the result of applying

•

the wrong voltage or phase is not covered under the
limited warranty.

CORRECT VOLTAGE AND PHASE

The HPWH units covered by this instruction manual can
be ordered with multiple power supply voltage and phase
congurations. Ensure the power supply voltage and phase
at the job site matches the power supply ratings listed on the
HPWH rating label BEFORE INSTALLATION BEGINS.

Voltage applied to the HPWH should not vary more than +5% to

-10% of the voltage requirement listed on the HPWH rating label
for satisfactory operation.

Energizing the HPWH with the wrong voltage and/or phase may
cause permanent damage to HPWH components. Damage
resulting from applying the wrong power supply voltage or phase
to the HPWH is not covered under the limited warranty.

Electrical Shock Hazard

Before removing any access panels or

•

servicing the water heater, make sure
the electrical supply to the water heater
is turned “OFF.”

Failure to do this could result in death,

•

serious bodily injury, or property
damage.

BRANCH CIRCUIT DISCONNECT SWITCH

The power supply wiring and equipment grounding must be
installed in accordance with local codes or, in the absence of
local codes, the National Electrical Code, ANSI/NFPA 70 or the
Canadian Electrical Code, CSA C22.1.

Install an adequately fused disconnect switch as close to the unit
as possible. See unit rating label for maximum fuse size (MFS).

Run the power supply lines from the disconnect to the control box
at the side panel of the unit. Connect the lines to the terminals on

input side of power distribution block L1 & L2 for single phase and
L1, L2 & L3 for three phases. Connect ground wire to ground lug.

See Minimum Circuit Ampacity & Maximum Fuse Size on page
12 for wire, fuse and breaker sizing information.

TRANSFORMER CONFIGURATION 208 VAC MODELS

The transformer leads must be changed on units connected to
a 208 VAC power supply as described below. See Unit Wiring
Diagrams-Fuse Sizes on pages 32-36 for component locations.

BEFORE CONNECTING THE THERMOSTAT
the HPWH momentarily and measure the voltage to the primary
winding of the transformer at the F3 fuse block. If the measured

, turn on power to

voltage is above 215 VAC no changes are necessary.

If the measured voltage is 215 VAC or less, then the primary
leads of the transformer must be changed from the 230 VAC tap
to the 208 VAC tap. Do this by disconnecting the orange wire
from the transformer primary terminal and replacing with the
red wire. Before reapplying power, ensure orange lead is safely
isolated with a wire nut and electrical tape.

WATER CONNECTIONS

Water piping must be installed in accordance with the instructions
in this manual and all local plumbing codes having jurisdiction.
See Figure 7 and Figure 8 on page 18 and the Piping Diagrams
on page 41 as a reference for these instructions.

INSTALLATION INSTRUCTIONS

1. This HPWH unit is not designed to supply hot water directly
to hot water xtures. The HPWH unit must be installed with a
separate storage tank as shown in the water piping diagrams
in this instruction manual.

2. Water lines installed between the storage tank and the HPWH
unit MUST NOT be less than the water pipe connection sizes
on the unit. See Table 4 on page 13.

3. The HPWH should be plumbed directly to the storage tank.

4. The cold water supply must be connected directly to the
storage tank at a low connection port on the storage tank
on single tank and two tank preheat piping congurations for
optimal efciency. See Figure 7 and Figure 8 on page 18.

5. The cold water supply MUST NOT be connected the inlet
(entering/return) water line to the HPWH unit.

6. The outlet (supply) water from the HPWH unit should connect
to a middle or lower port on the storage tank.

7. The inlet (return) water from the HPWH unit should connect
to a port on the storage tank lower than the outlet.

8. A heat trap should be installed between the storage tank and
the backup water heater on two tank preheat systems. See
Piping Diagram on page 41.

9. A T&P valve must be installed in the designated opening on
the storage tank per the tank manufacturer’s requirements.
See Temperature - Pressure Relief Valve on page 14.

10. Factory installed water pumps can provide the unit specied
water ow for up to a total of 50 equivalent feet of piping
between the HPWH unit and the storage tank. IE: 25
equivalent feet of inlet piping and 25 equivalent feet of outlet
piping. Do not exceed this maximum equivalent feet on
models equipped with factory-installed pumps.

11. For optimal performance minimize the equivalent length of
water piping between the HPWH and storage tank.

12. Building hot water recirculation loop should be connected to
the inlet of the backup water heater on two tank preheat
congurations or to the storage tank on single tank
congurations. The recirculating pump MUST BE controlled
by a eld supplied thermostat installed in the building
recirculation return line near the storage tank or back up
heater. The thermostat should stop pump operation the
moment the recirculation line is hot.

13. Use swing-type check valves (not spring-loaded types) on
the water outlet lines of all HPWH units plumbed in parallel to
prevent hot water short-circuiting.

14. Water lines shared by parallel HPWH units must be large
enough to handle combined water ows. Flow rates through
the heat pumps and tank(s) must be balanced. See Table 1
on page 9 for HPWH unit ow rates.

17

15. All components in the hot water supply system must be

TANK THERMOSTAT

TANK THERMOSTAT

adequately sized to meet peak water ow requirement

16. When the HPWH unit is installed above the storage tank
install a Tee tting at a high point in the outlet water line
leaving the unit. Install a purge valve, or if required by local
code, a T&P valve (temperature and pressure relief) in a
branch of the Tee tting that can be used to purge air from
the HPWH unit during start up. See Figure 7 and Figure 8.

17. DO NOT install a (T&P) relief valve in the outlet line of the
HPWH unit unless required by local code.

18. Dielectric unions should be installed a the inlet and outlet
water lines to the HPWH unit.

19. All HPWH water piping must be insulated.

SINGLE TANK CONFIGURATION

The HPWH must be plumbed to storage tank. The maximum
stored water temperature the HPWH unit can produce in the
storage tank is 140°F (60°C). Figure 7 shows a typical storage
tank piping conguration. Tank ports must be large enough to
handle the peak water ow rates through the water heating
system. See Piping Diagrams on page 41 for detailed piping
diagrams.

Purge Valve or T&P

(purge air from system)

Purge Valve or T&P

(purge air from system)

OUTLET

(SUPPLY)

INLET

(RETURN)

ISOLATION

VALVES

HPWH

STORAGE

TANK

DIGITAL TA NK
THERMOSTAT

SUPPLY

T&P VALV E

OPENING

PRE-HEATED

WATER OUT

HOT

OUTLET

BACKUP

WATER

HEATER

(OPTIONAL)

PRE HEATED

WATER INLET

DUCT

OUTLET

(SUPPLY)

INLET

(RETURN)

ISOLATION

VALVES

REMOTE TEMPERATURE
SENSOR OR MECHANICAL

HPWH

STORAGE

TANK

DIGITAL TA NK
THERMOSTAT

Figure 7

T&P VALV E

OPENING

COLD
INLET

SUPPLY

DUCT

HOT

OUTLET

REMOTE TEMPERATURE
SENSOR OR MECHANICAL

COLD
INLET

Figure 8

CONDENSATE DRAIN LINE

The HPWH unit must be plumbed to permit condensate drainage.
Drain piping connected to the HPWH unit should be a minimum
3/4 inch PVC or equivalent. A condensate trap must be used to
overcome the internal vacuum to permit proper drainage. See
Figure 9 below for recommended drain trap dimensions.

The condensate must be discharged to a suitable drain. If a drain
is inaccessible, use a condensate pump.

CONDENSATE TRAP

(All dimensions in inches)

HPWH

UNIT

3.00

6.00

3.00

TWO TANK PRE HEAT CONFIGURATION

When water temperatures above 140°F (60°C) are required the
HPWH and storage tank are piped in series (upstream) with a
backup water heater. See Water Temperature on page 10. The
backup water heater will raise the temperature of the preheated
water to the nal system temperature required. Figure 8 shows a
typical preheat piping conguration.

Figure 9

STANDARD TANK THERMOSTAT

Standard tank thermostats (Aquastat) already installed in the
storage tank may be used instead of the factory supplied Digital
Tank Thermostat if desired. Ensure the standard tank thermostat
is installed the lower third of the tank. Wire the existing tank
thermostat to the HPWH terminal strip. See Standard Tank
Thermostat Wiring on page 38.

18

DIGITAL TANK THERMOSTAT INSTALLATION

AIR FLOW AND DUCTING

1. Mount the thermostat on the storage tank jacket when or at
a suitable location close to the storage tank, see Figure 10.

2. Install three conductor low voltage wiring between the
thermostat’s terminal strip and the HPWH unit’s terminal
strip as shown in the Digital Tank Thermostat Wiring on page

37. Use standard 18 AWG thermostat wire or equivalent.

TEMPERATURE SENSOR INSTALLATION

The HPWH unit is shipped from the factory with a Digital Tank
Thermostat that includes a Temperature Sensor and a Sensor
Well. To install the Sensor Well:

1. Coat the Temperature Sensor and the inside of the Sensor
Well with heat transfer compound (paste) such as Honeywell
P/N 107408 or equivalent.

2. Secure the Temperature Sensor inside the Sensor Well with
the supplied clip or with an appropriate stop.

3. Check the condition of the anode rod(s) on existing storage
tanks and replace if depleted.

4. Install the sensor well in the storage tank’s designated
temperature control opening. Typically a 3/4” female NPT
tting in the lower portion of the storage tank.

5. DO NOT install Sensor Well or temperature sensor in the
upper half of the storage tank.

6. Do not install Sensor Well near the cold water supply
connection to the storage tank to prevent short cycling.

7. Install two conductor low voltage wiring between the
Temperature Sensor and Digital Tank Thermostat terminal
strip as shown in the Digital Tank Thermostat Wiring on page

37. Wiring can be installed up to 650 feet using 24 AWG
thermostat wire or equivalent.

HPWH

STORAGE

TANK

BACKUP

WATER

HEATER

DIGITAL TA NK
THERMOSTAT

REMOTE TEMPERATURE
SENSOR AND SENSOR WELL

GENERAL GUIDELINES

Review Locating The Water Heater on page 10, and this
section prior to connecting ductwork to the HPWH. See Features
And Components on page 8 to locate components.

Breathing Hazard - Carbon Monoxide Gas

Do not duct air from a garage or other
space where potentially harmful fumes
from solvents, chemicals or exhaust
from automobiles are present into any
other space in the building structure.

Gas and carbon monoxide detectors
are available.

Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.

The supply (outlet) air from a HPWH installed in a garage or a
unit drawing return (inlet) air from a garage or any area where
solvents or other chemicals that emit potentially harmful fumes
are stored or automobiles are located must never be ducted to
any other space inside the building structure. This would include
all occupied and unoccupied spaces such as attics or basements.
Potentially harmful fumes and vapors could be introduced into
occupied spaces. See Unit Placement on page 16.

DUCT SIZING

Supply and return air ducting must be sized properly to insure
adequate airow. Table 6, Table 7 and Table 8 on page 21
provide requirements for the total equivalent supply and return
duct lengths allowed. These tables are based on the most
common duct material options available today. Exceeding those
maximum lengths will adversely affect the operation of the heat
pump.

DUCT INSULATION

The cooled air from the HPWH may be below room dew point.
Insulate the supply duct to prevent dripping from moisture
condensing on the duct.

It is not necessary to insulate return ducts unless the air in the
return duct is lower than the room air. Also consider insulating all
ductwork to reduce blower noise from the unit.

MAKE DUCT CONNECTIONS

Install all ductwork to and from unit in accordance with all
applicable codes. Duct construction must allow unit to operate
within the limits of the unit external static pressure as in the
HPWH unit’s performance and specication sheets. See Table
1 on page 9 also.

Use exible connections to minimize duct-to-duct alignment
problems and noise transmission.

Install ductwork, accessory grilles, and plenums so that they do
not restrict access to lter and so they prevent dirt, dust, and
debris from settling in unit.

BUILDING AIR PRESSURE

When installing ducting to or from an alternate location (other
than the installed space) both the supply (outlet) and return
(inlet) air may need to be ducted to prevent positive or negative
building air pressure conditions within the installed space.

Figure 10

19

Negative Pressure

Ducting supply air only to an alternate location, such as the
outdoors, may cause excessive negative air pressure inside the
building envelope.

Excessive negative pressure inside the building structure may
result in cold or hot air from outdoors being drawn inside the
building and place additional load on space heating and cooling
equipment. Negative air pressure in buildings can also cause
reverse ow in chimneys and gas vents.

Positive Pressure

Ducting return air only from an alternate location, such as the
outdoors, may cause excessive positive air pressure inside the
building envelope.

Excessive positive pressure inside the building structure may
place additional load on space heating and cooling equipment by
interfering with the delivery of conditioned air.

WHEN TO INSTALL DUCTING

HPWH units are often installed in unoccupied spaces or
equipment rooms where there is an ample source of ambient
heat and no need to redirect the supply air to another location.
Ductwork is not necessary in these circumstances. See Heat
Source and Conditioned Space on page 10 and Unconditioned
Space on page 11.

Typical applications when ducting is installed.

• Duct supply (outlet) air to alternate location for spot cooling
or discard supply air not wanted in the installed space.

• Duct return (inlet) air from an alternate location (outdoors,
warm equipment room) to optimize efciency.

SUPPLY AIR DUCTING

Observe and follow these guidelines and instructions when
installing supply (outlet) air duct:

DANGER

Sharp Spinning Blades!

The blower operates at a high RPM that can cause injury
prevent inadvertent access to the blower opening, supply
ducting or other suitable means to prevent access must
be provided.

. To

to 11°C) as it ows through the HPWH unit. If the return air
to the HPWH unit is derived from a location that is above
80°F (27°C) the supply air from the HPWH unit will not be
suitable for offsetting the building cooling load. This will
often be the case when the return air is ducted from a warm
equipment room or from the outdoor atmosphere. In these
circumstances do not duct supply air to another location for
spot cooling.

6. Ducting supply air only to an alternate location, such as the
outdoors, may cause excessive negative air pressure inside
the building envelope.

Provision must be made to prevent a negative pressure in
the installed space or building envelope. Return air must be
supplied to the HPWH from the alternate location through
ducting or louvers that communicate with the alternate
location where the supply ducting terminates. See the Return
Air Ducting section that follows.

RETURN AIR DUCTING

Observe and follow these guidelines and instructions when
installing return (inlet) air duct:

1. All ductwork and plenums shall be eld supplied or fabricated.

2. The total equivalent length of all supply and return air ducting
must not exceed the maximum equivalent lengths shown in
Table 6 or Table 7 on page 21.

3. When installing return air duct to the HPWH unit a eld
supplied/fabricated lter access door must be installed.

4. Ducting return air only from an alternate location, such as the
outdoors, may cause excessive positive air pressure inside
the building envelope.

Provision must be made to prevent a positive pressure in
the installed space or building envelope. Supply air must be
supplied to the HPWH from the alternate location through
ducting that communicates with the alternate location from
where the return air is derived. See the preceding Supply Air
Ducting section.

5. If the alternate location where return air is derived from
has temperatures above 95°F (35°C) for extended periods
the accessory High Ambient Air Kit should be installed for
optimum efciency. See page 39.

BLOWER ASSEMBLY ADJUSTMENTS

1. When duct work is not field connected to the supply air
outlet on the HPWH unit a field supplied safety guard
must be installed over the supply air connection. Failure
to comply could result in severe injury.

2. All ductwork and plenums shall be eld supplied or fabricated.

3. The total equivalent length of all supply and return air ducting
must not exceed the maximum equivalent lengths shown in
Table 6 or Table 7 on page 21.

4. Cooling output (supply air) from the HPWH is supplemental
only and must not be factored into sizing calculations for
space cooling equipment. Cooling output is only produced
when the HPWH is operating to satisfy a water heating
demand. Once the storage tank temperature is satised,
the HPWH will stop until the next water heating demand is
initiated regardless of space cooling needs.

5. Depending on the temperature of the air entering the HPWH
unit the supply air may not be suitable for supplemental
space cooling purposes.

The air temperature drops approximately 12°F to 20°F (7°C

DANGER

Sharp Spinning Blades!

The blower operates at a high RPM that can cause injury
prevent inadvertent access to the blower opening, supply
ducting or other suitable means to prevent access must
be provided.

The HPWH blower is a belt driven assembly. The blower belt
and sheaves are factory pre-set and should not require any eld
adjustment. The blower assembly should be checked to ensure
the blower wheel moves freely and that sufcient tension is on
the blower belt. If belt looseness is suspected, check the blower
maintenance section of the manual for re-set recommendations.

20

. To

TABLE 6

METAL DUCT

DUCT SIZE (INCHES)

6 8 10 12 14 16 18 20 22 24

MODEL CFM EXT (in WG)

WH-35 1040 0.35 3 14 41 102 208 417

WH-55 1650 0.35 6 17 41 90 173 308

WH-75 2150 0.35 3 10 25 52 105 188 313

WH-100 3200 0.35 6 14 31 59 107 180 292

WH-115 3200 0.35 5 12 26 49 87 148 234

WH-140 3800 0.35 4 9 18 35 64 110 170 262

WH-170 4900 0.35 5 12 22 39 67 107 167

MAXIMUM EQUIVALENT LENGTH (FEET)

ELBOW SIZE (IN)

EQUIVALENT FEET

6 8 10 12 14 16 18 20 22 24

18 23 29 35 41 47 53 58 64 70

ONE 90° ELBOW

Note 1: Gradual rectangular to round transition must be used. Angle not to exceed 30°

Note 2: If elbows are used, equivalent length of elbows must be added to duct length.

TABLE 7

FLEXIBLE DUCT

DUCT SIZE (INCHES)

6 8 10 12 14 16 18 20 22 24

MODEL CFM EXT (in WG)

WH-35 1040 0.35 6 18 45 93 185

WH-55 1650 0.35 3 8 18 40 77 137

WH-75 2150 0.35 5 11 23 47 83 139

WH-100 3200 0.35 3 6 14 26 48 80 130

WH-115 3200 0.35 5 12 22 38 66 104

WH-140 3800 0.35 4 8 16 29 49 76 116

WH-170 4900 0.35 2 5 10 18 30 48 74

ELBOW SIZE (IN)

EQUIVALENT FEET

6 8 10 12 14 16 18 20 22 24

18 23 29 35 41 47 53 58 64 70

ONE 90° ELBOW

Note 1: Gradual transition must be used. Angle not to exceed 30°

Note 2: If elbows are used, equivalent length of elbows must be added to duct length.

MAXIMUM EQUIVALENT LENGTH (FEET)

TABLE 8

DUCT CONNECTION SIZES

UNIT SUPPLY RETURN**

VERTICAL HORIZONTAL VERTICAL HORIZONTAL

WH-35 14 14 20.25 27

WH-55 16 16 24 35

WH-75 18 18 24 47

WH-100 22 22 38 49.5

WH-115 22 22 38 49.5

WH-140 24 24 38 49.5

WH-170 28 28 38 63.75

21

INSTALLATION CHECKLIST

The list below represents some of the most critical installation
requirements that, when overlooked, often result in operational
problems, down time and needless parts replacement. This
is not a complete list. Before performing any troubleshooting
procedures use the list below to check for installation errors.
Costs to correct installation errors are not covered under the
limited warranty. Ensure all installation requirements and
instructions in this manual have been followed.

LOCATION

1. Ensure the HPWH is located where there is a adequate
supply of ambient heat for optimal performance or that the
HPWH is ducted to such a location.

2. Ensure required clearances are maintained and there is
access for servicing. See Clearances on page 11.

3. Ensure the HPWH is properly supported. See Ceiling
Suspension and Pad Mounting on page 16.

AIR FLOW & DUCTING

4. Ensure all supply and return ductwork connected to the
HPWH is properly sized, does not exceed maximum
equivalent length requirements and is installed according to
the instructions in this manual. See Air Flow and Ducting on
page 19.

5. Ensure all supply duct work is insulated to prevent
condensation from forming on the ductwork.

6. Ensure all return air duct is insulated if the return air
temperatures are expected to fall below the surrounding
room air temperature during normal operation.

WATER PIPING

7. Ensure the outlet (supply) and inlet (return) water piping
connected to the HPWH are not less than the connection
size on the unit. See Table 1 on page 9.

8. Ensure swing-type check valves (not spring-loaded types)
are installed on outlet lines of all heat pumps plumbed in
parallel to prevent hot water short-circuiting.

9. When the HPWH is connected to a storage tank ensure the
storage tank is equipped with a properly rated and sized
Temperature and Pressure (T&P) relief valve. Refer to the
storage tank manufacturer’s instructions for T&P valve sizing
and installation requirements.

NOTE: This is a critical installation requirement that must
not be overlooked. Call the toll free technical support
phone number on the back cover of this manual for further
assistance.

10. DO NOT install a T&P valve in the outlet (supply) water line
of the HPWH unless required by local code.

11. Ensure the maximum lengths of 25 equivalent feet of
supply piping and 25 equivalent feet of return piping are not
exceeded on HPWH units equipped with a factory installed
circulation pump. Exceeding these lengths will cause the unit
to malfunction and/or the control system to lock out.

12. Ensure isolation valves are installed on the HPWH supply
and return water line at the storage tank for servicing and
purging the air from the HPWH during start-up.

13. Ensure the cold water supply is not connected directly to or
Tee tted to the inlet water line on the HPWH. See the Service
and Installation Notes for Inlet & Outlet Water Temperature
on page 10. See Figure 7 and Figure 8 on page 18.

14. On two tank preheat piping congurations ensure the cold

water supply is not connected to the back up water heater.

15. Connect building recirculation loop piping to the backup
water heater inlet on two tank preheat piping congurations.

16. Ensure the building recirculation loop pump is controlled by a
eld supplied line thermostat and that it stops the pump when
the recirculation line is hot. See Building Recirculation Pump
Wiring Diagram on page 40.

17. When the HPWH unit is installed above the storage tank
install a Tee tting at a high point in the outlet water line with
a purge valve to bleed air during start up.

18. Though not required, the manufacturer recommends
installing a strainer at the inlet water line on the HPWH to help
prevent scale build up in the heat exchanger. Service costs to
clear blockages from the HPWH unit’s heat exchanger due to
debris are not covered under the limited warranty.

CONDENSATE DRAIN

19. Ensure there is a water trap installed in the condensate line
at the HPWH. Condensate will not drain without a water trap.

20. Ensure the condensate drain is properly connected to
the HPWH and draining freely to a suitable oor drain or
condensate lift pump that discharges condensate to a remote
location. See Condensate Drain Line on page 18.

ELECTRICAL

21. BEFORE ENERGIZING THE UNIT ensure the power supply
voltage and phase matches the requirements on the HPWH
rating label. Damage resulting from applying the wrong
voltage or phase is not covered under the limited warranty.

22. On HPWH units connected to 208 VAC power supplies ensure
the transformer has been properly congured. Damage
caused by failure to congure the transformer properly is
not covered under the limited warranty. See Transformer
Conguration 208 VAC Models on page 17.

23. Ensure the power supply breaker or the fuses disconnect
switch are within the requirements for the unit as shown on
the HPWH rating label.

24. Ensure the power supply wiring meets the MCA (Minimum
Circuit Ampacity) requirements shown in this manual and on
the HPWH rating label.

25. Ensure the HPWH is properly grounded according to the
instructions in this manual and local code requirements.

26. Ensure the power supply connections to the HPWH are
connected properly and securely tightened.

27. Ensure all electrical connections in the HPWH control panel
are securely tightened.

28. When the factory supplied Digital Tank Thermostat is used:

• Insure the thermostat and sensor are installed
properly. See Digital Tank Thermostat Installation and
Temperature Sensor Installation on page 19.

• Ensure the Temperature Sensor and supplied Sensor
Well have been installed in a designated temperature
control opening in the lower part of the storage tank.

• Ensure the supplied Temperature Sensor is coated with a
suitable heat transfer compound (paste).

• Ensure the Temperature Sensor has been properly wired
to the terminal strip of the Digital Tank Thermostat. See
Figure 15 on page 37.

22

START UP

This start-up refers to several tools and test instruments needed
to complete the procedure. See Required Tools and Materials on
page 16.

Electrical Shock Hazard

Turn off power to the water heater

•

before performing any service.

Label all wires prior to disconnecting

•

when performing service. Wiring errors
can cause improper and dangerous
operation.

Verify proper operation after servicing.

•

Failure to follow these instructions can

•

result in personal injury or death.

1. Ensure the Installation Checklist has been completed.

2. Ensure the HPWH, storage tank and water system has been
purged of air and all valves are in the position for normal
operation.

3. Turn on power at the circuit breaker or disconnect switch
serving the HPWH.

If the HPWH does not start immediately:

• Wait 5 minutes in case the anti short cycle timer has
halted operation. This control system feature protects
the HPWH from rapid short cycling that can cause
permanent damage to the unit.

• Ensure the operating set point on the tank temperature
control is adjusted high enough to initiate a call for heat.
The recommended setting is 120°F to 140°F (29°C to
60°C).

• DO NOT set the operating set point on the tank
temperature control above 140°F. See Water
Temperature Range on page 7.

• Ensure the Differential Set Point is not set too high.
Higher differential settings will cause greater temperature
swings in system temperature. Lower differential settings
can cause unit short cycling. The recommended setting
is 3°F.

• If the unit does not start after all of the above procedures
have been followed. Refer to the troubleshooting section
of this manual.

4. Securely attach surface mount thermometers or temperature
sensors to the inlet (entering) and outlet (leaving) water lines
near the HPWH cabinet. If there are thermometers installed
in the inlet and outlet in close proximity to the HPWH water
connections they can be used for the following check.

Ensure the water outlet (supply) and inlet (return) valves
are fully open. Start the HPWH and allow it to operate for 5
minutes. With the HPWH operating record the inlet and outlet
temperatures.

During normal operation, the outlet line should be 8°F to 12°F
(4°C to 7°C) hotter than the inlet line. This is the temperature
rise through the heat exchanger inside the HPWH unit.

Note: Temperature rise and water ow rate through the heat
exchanger inside the HPWH are uniformly linked. As water

ow is decreased the temperature rise will increase and as
water ow is increased the temperature rise will decrease.
Because of this relationship between temperature rise and
ow rate this test can be useful to determine if the ow rate
through the heat exchanger is adequate. Other factors may
also affect water ow rate and temperature rise such as
debris or lime scale build up inside heat exchanger or water
pump operation.

If the temperature rise through the HPWH is consistently
lower than 8°F the outlet (supply) valve can be throttled
slightly closed to reduce the water ow rate. This may be
necessary on installations with a minimum of water piping
between the HPWH and the water system or tank.

Throttling should be done in small increments, no more than
1/8 turn of the valve handle at a time. The HPWH must run
be allowed to run for approximately 5 minutes between each
adjustment before the temperature rise is measured again.
If the outlet valve is throttled during start up, mark the valve
position and remove the valve handle to ensure it is not
accidentally changed.

If the temperature rise through the HPWH is consistently
greater than 12°F the water ow may be restricted. Ensure
all water valves between the HPWH and the tank or water
system are fully open. Ensure the water pump inside the
HPWH is running. If the temperature rise continues to be
excessive call the toll free technical support phone number
on the back cover of this manual for further assistance.

5. Using thermometers or temperature sensors, measure the
temperature of the return (inlet) air to the HPWH and the
supply (outlet) air leaving the unit. The outlet air temperature
should be 12°F to 20°F (7°C to 11°C) cooler than the inlet air.

Air temperature and ow rate through the heat pump
determines what this temperature difference will be. The
higher the ow rate the lower the temperature differential will
be. The higher the air temperature, the higher the differential
will be.

If the temperature differential between return and supply air
is not within the range stated above ensure the air lters are
clean and there is nothing blocking the air ow on either side
of the airstream or ductwork attached to the HPWH. Ensure
the ductwork is not smaller than the minimum required size
and or longer than the maximum length allowed in the Air
Flow & Ducting section of this manual. Ensure the evaporator
coil is not damaged (ns attened) or dirty.

If the temperature differential continues to be outside the
range mentioned above call the toll free technical support
phone number on the back cover of this manual for further
assistance.

6. When all of the above procedures are complete adjust
the tank temperature control set point to desired system
temperature, not to exceed 140°F (60°C). Remove all test
instruments and replace all cabinet doors.

23

DIGITAL TANK THERMOSTAT

LED

DISPLAY

OUTPUT

MT-511Ri

FACTORY SUPPLIED DIGITAL TANK THERMOSTAT - MODEL MT511Ri

Figure 11

OPERATION

When the water temperature in the storage tank as sensed by
the Digital Tank Thermostat’s temperature sensor reaches the
Tank Temperature Set Point the thermostat will end the heating
cycle and HPWH unit will shut down.

A heating cycle will be activated again when the water
temperature sensed at the temperature sensor in the storage
tank drops below the Tank Temperature Set Point minus the
Differential Set Point.

See Figure 11 above as a reference for the instructions that
follow.

Notes: The Tank Temperature Set Point must never be set higher
than 140°F (60°C). This is the maximum temperature the HPWH
can heat the water in the storage tank to. See Maximum System
Temperature on page 10.

The factory Differential Set Point is 3°F (1.7°C). This is the
recommended setting. The Differential Set Point should never be
set lower than the factory setting to ensure the HPWH unit does
not short cycle. This Differential Set Point should not be set any
higher than 5°F (2.8°C).

TANK TEMPERATURE SETTING

1. Press and hold the SET button for 1 second until [ t ] appears

on the LED display then release the button.

2. Use the UP and DOWN buttons to adjust to the desired tank

temperature set point.

3. When complete press the SET button to save the change.

DIFFERENTIAL SETTING

1. Press and hold the UP and DOWN buttons simultaneously
for 5 seconds until [ dIF ] appears on the LED display then
release the buttons.

2. Use the UP and DOWN buttons to adjust to the desired
differential set point.

3. When complete press the SET button to save the change.

4. The operating mode of the thermostat will be shown on the
LED display next as:

[ CoL ] for Refrigeration/Cooling mode or

[ Hot ] for Heating mode.

UP

BUTTON

SET

SET

BUTTON

DOWN

BUTTON

Note: the factory for operating mode is [ Hot ] and should not
be changed.

TEMPERATURE UNITS SETTING (°F/°C)

To dene the temperature units that thermostat will display:

1. Press and hold the UP and DOWN buttons simultaneously

for 30 seconds until [ Uni } appears on the LED display then
release the buttons.

2. Use the UP and DOWN buttons to select [ °F ] or [ °C ].

3. When complete press the SET button to save the change.

4. [ FAC ] will appear on the LED display after saving the

change and the display will then return to normal operation
and display the tank temperature.

Note: Each time the temperature unit display setting is
changed all set points must be re-congured

DISPLAYING MIN/MAX TANK TEMPERATURES

The digital thermostat stores the minimum and maximum tank
temperature readings in memory. To display this data:

1. Press the UP button.

2. The recorded minimum temperature will be displayed
followed by the recorded maximum temperature.

3. Note: to reset the recorded values press and hold the UP
button while the minimum and maximum values are being
displayed.

4. [ rSt ] will appear conrming that the recorded minimum and
maximum temperatures have been cleared.

DISPLAY SIGNALS

During normal operation the LED display will show the actual
measured tank temperature from the tank temperature sensor.

The LED light located above the temperature display (Output)
indicates that the heat pump, the thermostat output, is on.

If the temperature sensor is detached or the temperature is out
of the specied range [ Err ] will be displayed on the LED display.

24

MAINTENANCE AND SERVICE

ROUTINE MAINTENANCE

Warning: When possible, disconnect all power to the unit and
follow the prescribed lock - out/tag - out procedure to prevent

accidental electrocution. Should the unit have to be serviced
with live electricity, only trained and qualied technicians should
carry out the service. Failure to follow all of the safety warnings
may result in serious injury or death.

The temperature-pressure relief valve must be manually operated
at least once a year. Caution should be taken to ensure that (1)
no one is in front of or around the outlet of the temperature­pressure relief valve discharge line, and (2) the water manually
discharged will not cause any bodily injury or property damage
because the water may be extremely hot. If after manually
operating the valve, it fails to completely reset and continues to
release water, immediately close the cold water inlet to the heat
pump, follow the draining instructions in the storage tank manual,
and replace the temperature-pressure relief valve with a properly
rated/sized new one.

If you do not understand these instructions or have any questions
regarding the temperature-pressure relief valve call the toll free
number listed on the back cover of this manual for technical
assistance.

AIR FILTERS

Note: If return duct is connected to the unit, be sure to install a

Inspect and tighten all bearing collar and wheel set screws after

every six months. During inspection, visually check the drive belt
for wear or cracking. Replace as necessary, but do not apply any
belt dressing products.

Inspect all set screws on the pulleys, wheel and bearing lock
collars. Check the belt for proper tension and alignment.

Clean the blower wheel periodically as material buildup on the
blades can cause a wheel imbalance that may lead to wheel or
bearing failure.

The pillow block bearings come pre-lubricated from the factory.
These bearings should be lubricated at least once per year.
The recommended lubricant is Shell Alvania #2 or S3. Caution:

bearing. Apply the grease slowly as the shaft is rotating.
Motor grease is not compatible for bearings. Only use grease
designated for bearing use.

BLOWER MOTOR

Warning: before performing any maintenance on the blower
motor, disconnect all power to the unit and follow the prescribed
lock-out/tag-out procedure.

Every six months visually inspect the blower motor. Clean off any
dust, grease or oily buildup and vacuum out any cavities in the
motor. It may be necessary to periodically disassemble the motor
for a more thorough internal cleaning.

Motors are permanently lubricated from the factory. It is not
necessary to lubricate the motor upon start-up or lubricate as
part of maintenance.

of hot water to remove the dirt and lint. To remove grease, apply

DRAIN PAN

Warning: Read all of the warnings on the bottle of the cleaning
products used for drain pan cleaning. Follow all instructions for
personal protection and safe application of the products. Before
cleaning the drain pan, disconnect all power to the unit and follow
the prescribed lock-out/tag-out procedure.

The condensate pan and drain line must be checked for
cleanliness, growth and blockage at least every six months.

To clean drain pan, start by disconnecting the power to the unit.
Wear the appropriate personal protective equipment prescribed
by the cleaning product instructions. Apply the cleaning solution
and scour the sides of and bottom of the drain pan. Remove all
large solid particles that could potentially clog up the drain line.
If algae or mold are found growing in the pan, after cleaning,
apply a mild bleach and water solution and brush on the growth
areas. Rinse the drain pan thoroughly with water and dry for a

BLOWER ASSEMBLY

Before performing any maintenance on the blower assembly,
disconnect all power to the unit and follow the prescribed lock­out/tag-out procedure.

EVAPORATOR COIL

Warning: Read all of the warnings provided for the cleaning
products used for refrigeration coil cleaning. Follow all
instructions for personal protection and safe application of the
products. Before cleaning evaporator , disconnect all power
to the unit and follow the prescribed lock-out/tag-out procedure.

steps listed below:

1. Disconnect all power to the unit and follow the prescribed
lock-out/tag-out procedure.

2. Wear the prescribed personal protective equipment
prescribed from the cleaning product instructions.

3. Install a block-off sheet to prevent splash over into the dry
sections of the WH HPWH.

4. Prepare the cleaning solution as prescribed from the cleaning

sprayer.

5. Start spraying both sides of the coil keeping the nozzle
perpendicular to the coil at least 6 inches from the coil face.
Do not exceed 600 psi.

6. Thoroughly rinse the cleaned coil with cool, clean water.

7.

8.

9. Replace all panels on the unit and wipe down any standing
cleaning solution or water on or around the unit.

25

CLEANING INTERNAL INSULATION

BRAZE PLATE CLEANING INSTRUCTIONS

Inspect the internal insulation on a yearly basis for any microbial
growth. The insulation never has to be cleaned unless microbial
growth is detected. If microbial growth is detected, follow the
removal steps below:

1. Disconnect all power to the unit and follow the prescribed
lock-out/tag-out procedure.

2. Wear the prescribed personal protective equipment
prescribed from the cleaning product instructions.

3. Remove as much dirt and organic material from the insulation
using a vacuum device with a HEPA lter (99.97% efcient
at 0.3 micron particles). Be careful not to tear the insulation
during the cleaning procedure.

4. Apply the microbial cleaning agent as prescribed by the
application and usage instructions.

5. Allow the unit to dry thoroughly.

6. If necessary, apply an anti-microbial agent on the insulation
per the instructions provided on the product label.

7. Discard collected microbial contaminants as required by
local or state codes.

In some applications the heat exchanger may be subjected to
severe uid conditions, including high temperture hard water
conditions, causing accelerated scaling and corrosion rates, and
will diminish performance.

It is important to establish regular cleaning schedules, A 5%
solution of Phosphoric Acid or Oxalic Acid may be considered.
Other types of solutions can be obtained from your local
wholesaler. Make sure cleaning solution is applicable for stainless
steel and copper and all directions are followed.

Do not heat solution. Be sure to ush heat exchanger with fresh
water after cleaning. See Figure 22.

Figure 12

26

TROUBLESHOOTING

PROBLEM POSSIBLE CAUSES CORRECTIONS

Heat pump is too noisy.

Water on oor around

the heat pump and/or

water tank.

Heat pump is not running -

electrical issues.

Heat pump is not running -

high pressure fault

Heat pump is not running -

low pressure fault

1. Sheet metal fasteners are loose.

2. Operating vibration is transferring to oor or
building structure.

3. 3. Blower pulley assembly loose or out of alignment.

1. Tubing, valves, or ttings are leaking.

2. Heat pump is not leveled causing drain pan overow.

3. Make sure the condensate trap has been properly
installed.

4. Drain pan is overowing.

5. Condensation forming on the bottom of unit
(humid environments).

1. Circuit does not have adequate ampacity.

2. Short circuit or loose connection in eld wiring.

3. Short circuit or loose connection in unit electrical
cabinet.

4. Thermostat failure.

5. Phase Monitor fault (red light on phase monitor lit)

6. Defective anti-short cycle timer.

7. Compressor burn-out.

1. Thermostat setting too high

2. Room temperature over 95 F

3. Low water ow causes

A. unit pump is not operating

B. piping between the heat pump and storage tank

exceeds 50 equivalent feet

C. heat exchanger has scale buildup

D. shut off valves are partially closed

1. Room temperature below 50 F

2. Blower not operating at nameplate CFM - blower belt is
broken or out of alignment lters are dirty

3. Unit does not have adequate clearances obstructing air
ow

4. Loss of refrigerant

Tighten fasteners.

Place vibration dampeners underneath unit.

Tighten or align pulleys.

Repair leaks as necessary.

Shim unit to level. See installation section.

Condensate trap depth must maintain a water column during
operation.

Use pipe snake or compressed air to remove obstruction.

Cover bottom of unit with foam insulation.

Refer to nameplate for unit requirements.

Check eld wiring diagram. Tighten all connections.

Check for loose wiring and tighten.

Replace thermostat

Reset phase monitor

Unknown

Replace compressor (refer to compressor change-out
page)

Thermostat setting should not exceed 140 F.

Keep heat pump off until room temperature
is back in operating range

Low water ow corrections

replace unit pump

reduce piping or add booster pump

clean heat exchanger with a mild acid wash

open all shut off valves

Keep heat pump off until room temperature is back in

operating range

Correct air-ow issue

i.Replace or realign pulley assembly; tighten belt

at the adjustable pulley

ii. Replace ltersw

iii. Relocate unit to allow for even air ow

Find source of leak, repair and recharge

1. Thermostat setting is too low.

Water is never hot enough.

2. Heat pump/storage tank undersized for application.

3. Heat pump is not properly connected to storage tank.

4. Unit cooling coil is overcooling the space.

1. Insufcient air ow through the unit

2. Low room temperature

Cooling coil is icing.

3. Partial refrigerant loss

4. Defective TX valve

5. Clogged lter dryer

* Reset the heat pump by removing then restoring power to the unit at the breaker or from the manual switch. (There will be a three minute delay
before heat pump restarts.) If the heat pump cuts out again on LOW or HIGH PRESSURE, additional troubleshooting is necessary to nd the cause
DO NOT CONTINUE TO RESET THE HEAT PUMP, AS CONTINUED SHORT-CYCLING MAY STRESS OR DAMAGE INTERNAL COMPONENTS.

27

Set thermostat for storage tank to a higher temperature.

Increase size of storage tank or install gas or electric heater
to make up for shortfall.

Refer to eld piping diagrams for recommended piping.

If the room air temperature is too cool, a) use back up
water heating; b) duct cool air to another space; c) duct
warmer air from another space to the installed room.

Refer to “Heat pump is not running - low
section for correction suggestions.

If room air temperature is too cool, a) use back up water
heating; b) duct cool air to another space; c) duct warmer
air from another space to installed room.

Find source of leak, repair and recharge

Replace TX valve

Replace lter dryer

pressure fault”

CHECKING REFRIGERANT CHARGE

Servicing of the refrigeration circuit must only be performed
by agencies or individuals possessing Type II or Universal

This HPWH unit is factory charged with 134a refrigerant. See the
rating label on the HPWH unit and Table 9 for refrigerant charge
by weight. It should not be necessary to add or remove refrigerant
during installation or start up. Refrigerant lost during frequent
refrigerant pressure testing can cause low refrigerant conditions.

other potential problems before checking the refrigerant charge.

Check Air Flow

clean. Ensure the blower motor belt is not worn or loose. See
Figure 1 on page 8 for component locations. Correct any

Check Water Temperature Rise

Always check water temperature rise through the HPWH unit’s

See Start Up on page 23 for information on how to measure
the water temperature rise.

If the measured water temperature rise during start up was within
8°F to 12°F (4°C to 7°C) checking the charge is not necessary
unless other conditions warrant testing.

If the measured temperature rise through the HPWH unit is less
than 8°F (4°C) checking the charge is not necessary unless other
conditions warrant testing. Short water piping runs between the
HPWH and the storage tank will produce lower temperature rises
and are not problematic.

than 12°F (7°C) check for restrictions in the inlet and outlet water
piping connected between the HPWH unit and the storage tank.
On new installations ensure the maximum equivalent feet of inlet
and outlet piping was not exceeded. This is the most common
cause of excessive water temperature rise on new installations.
See number 11 on page 22.

SUBCOOLING CALCUL

1. Measure and record the liquid pressure at the liquid line
pressure test port inside the unit.

2. Convert the recorded liquid line pressure to saturated
temperature using Table 10.

3. Measure the liquid line temperature near the liquid line

pressure test port inside the unit.

4. Compare the liquid line temperature to the saturated
temperature in Table 10.

5. The difference between saturated temperature and liquid
line temperature is the subcooling. Subcooling normal range

should be 5°F to 15°F (2.8°C to 8.5°C).

SUPERHEAT CALCULATION

1. Measure and record the suction pressure at the suction line
pressure test port inside the unit.

2. Convert the recorded suction pressure to saturated
temperature.

3. Measure the suction line temperature near the suction line
pressure test port inside the unit.

4. Compare the suction line temperature to the to the saturated
temperature in Table 10.

ATION

5. The difference between saturated temperature and suction
line temperature is the superheat. Superheat normal range
should be 8°F to 12°F (4.4°C to 6.7°C).

TABLE 9

MODEL FACTORY CHARGE R134A

WH-35 2lbs, 15oz

WH-55 3lbs, 12oz

WH-75 6lbs, 5oz

WH-100 7lbs, 3oz

WH-115 7lbs, 14oz

WH-140 10lbs, 15oz

WH-170 13lbs, 5oz

TABLE 10

.egrahc tnaregirfer eht gnikcehc erofeb regnahcxe taeh lanretni

R134A SATURATED TEMPERATURE CHART

SATURATED

TEMPERATURE °F

erom si tinu HWPH eht hguorht esir erutarepmet derusaem eht fI

0 -18 7

5 -15 9

10 -12 12

15 -9 15

20 -7 18

25 -4 22

30 -1 26

35 2 30

40 4 35

45 7 40

50 10 45

55 13 51

60 16 57

65 18 64

70 21 71

75 24 79

80 27 87

85 29 95

90 32 104

95 35 114

100 38 124

105 41 135

110 43 146

115 46 158

120 49 171

125 52 185

130 54 199

135 57 214

140 60 229

145 63 246

150 66 263

155 68 281

SATURATED

TEMPERATURE °C

REFRIGERANT

PRESSURE (PSI)

28

CONTROL SYSTEM

CONTROL BOARD

The heart of the control system is the Control Board which is a printed circuit board (PCB) installed inside the control box. See Figure
13 below, Figure 14 on page 30 and the Wiring Diagrams on pages 32 to 36.

The Control Board is powered by 24 VAC from the transformer. The F4 fuse on the Control Board protects the secondary winding of
the transformer.

The Control Board has four (4) proving circuits that must be closed by either a factor-installed jumper wire or the dry contacts in an
external control to enable HPWH operation. The Control Board also has one (1) thermostat circuit that is factory wired to the HPWH
Terminal Strip. The factory supplied Digital Tank thermostat (see page 19) or a eld supplied standard tank thermostat is wired to
this thermostat circuit to regulate water temperature in the storage tank. See Figure 15 on page 37 and Figure 16 on page 38.

SERVICE NOTE: All ve (5) of these circuits must be closed circuits or the HPWH will not operate. See items 1-5 in Figure 13 below.
If the HPWH unit does not begin a heating cycle within 5 minutes (allowing time for the anti-short-cycle timer) after power is applied
ensure the thermostat is calling for heat (closed contacts). is unresponsive when power is applied

PRESSURE SWITCHES

The Control Board monitors two refrigerant pressure switches, a high and a low pressure switch. If the contacts on either switch open
during a heating cycle the control system will lockout and the compressor will be disabled. The blower and the pump will continue to
operate as long as a call for heat is present. The cause of the pressure switch contacts opening must be corrected and the control
system must be reset before the HPWH will resume compressor operation. See Table 11 for pressure switch activation pressures.

Low and High pressure switch LED lights on the Control Board will be energized during this fault condition as a diagnostic aid to
indicate which switch has cased the fault condition. See Figure 14 on page 30. The low pressure switch is on a time delay (Time
Safety By-Pass) to prevent nuisance lockouts during start up when the return (inlet) water may be below . This delay is set for 300
seconds from the factory.

TABLE 11

MODEL

WH-35 - WH-170

1

Remove the jumper when Phase
Monitor is used.

Remove the jumper when Push Button

2

Reset (NC contact) is used.

Remove the jumper when Compressor

3

Overload Module is used.

Remove the jumper when ON/OFF

4

Switch is used.

NOTE: 1-4 are all proving circuits for external
control dry contacts. These circuits must be
closed to enable operation. If any of these
circuits are open HPWH operation will be
disabled; compressor, blower and pump
will not run. Jumpers must be installed for
proving circuits 1-4 when external controls
are not in use. Tank Aquastat (thermostat)
must be connected to #5.

Contacts Close Contacts Open Contacts Close Contacts Open

35 PSI (241 kPa) ± 5% 15 PSI (103 kPa) ± 5% 250 PSI (1,724 kPa) ± 15% 350 PSI (2,413 kPa) ± 15%

LOW PRESSURE SWITCH

Normally Open - Close On Rise

CONTROL BOARD

1

2

3

HIGH PRESSURE SWITCH

Normally Closed - Open On Rise

To Pump Contactor
To Blower Contactor
To Compressor Contactor

Push

Button

Reset

4

To HPWH Terminal Strip

Tank Aquastat (thermostat)

From Transformer

24 VAC Power Supply

ON/OFF

Switch

To HP
Switch

HP Switch
Remote Alarm
(dry contact)

To LP Switch
Time Safety

LP Switch
Remote Alarm
(dry contact)

Figure 13

29

PHASE MONITOR

Some of the higher capacity models are equipped with Phase Monitor and Compressor Overload modules that interface with the Control
Board. See Table 12 on page 31.

• If all 3 phases of power are present and in sequence, the normally open contacts (Y/Y-OUT) will close when 24 volts is applied
between C and Y terminals. The green LED on the Phase Monitor will be energized.

• If the phases are out of sequence, or if one or more phase is dropped when power to the HPWH unit is turned on, the normally
open contacts (Y/Y-OUT) will not close and the control system will lockout. Compressor, blower and pump operation will be disabled

until the problem is corrected and the control system is reset. The red LED on the Phase Monitor will be energized.

• If a phase is dropped or becomes out of sequence while the HPWH is energized, the Phase Monitor contacts will open immediately
and and the control system will lockout. Compressor, blower and pump operation will be disabled until the problem is corrected and

the control system is reset. The red LED on the Phase Monitor will be energized.

COMPRESSOR OVERLOAD MODULE

The solid state sensor protectors provide excellent protection against high motor temperatures resulting from locked rotor, loss of charge,

or motor overload. The combination of low voltage sensing and time delay provide positive protection against low voltage conditions which
can occur in the pilot circuit in the event of a single phase condition on a three phase circuit.

There are two major components in the protection system:

1. The Protector Sensors are mounted internally in the motor windings. The characteristics of the sensor are such that a change in temperature

causes a change in the sensor’s electrical resistance, the relation between temperature and resistance remains stable and exact, so that

calibration of the protection system can be made on the basis of resistance readings.

2. The Control Module is a sealed enclosure containing a relay or triac, transformer, and several electronic components. Leads from the

internal motor sensors are connected to the module. As the motor temperature rises or falls, the resistance also rises or falls, triggering the

action of the control circuit at predetermined opening and closing settings.

DELAY TIMERS

Time Delay By-Pass (Low Pressure Switch Bypass):

When power is applied to the input, regardless of the state of the pressure switch,

the load is energized and timing begins. After the timing delay is complete, the pressure switch will control the load. The control is

reset by removing power during or after the time delay.

Anti-Short Cycle / Lockout Timer

:

With application of power, the load is energized. When the thermostat opens or when there is a
loss of power, the load is de-energized and the delay period begins. The compressor will not start again during the delay period. The
ICM203 provides true thermostat interruption protection, even in the presence of a trickle current.

HOW TO RESET THE CONTROL SYSTEM

Whenever control system

has

disable heating

(locked out)

power to

HPWH

unit must be turned off

and

on again to reset control system.

OPTIONAL FIELD SUPPLIED CONTROLS

• A field supplied low voltage momentary (reset) switch can be wired to the Control Board to reset the control system when it has

been disabled by a fault condition.

• A field supplied low voltage on/off switch can be added to turn the unit off. Note: high voltage would still be present inside the control

box,

turn off the main disconnect or breaker before performing any maintenance or service on the HPWH unit.

• The Control Board also has provision to activate field supplied external alarms (audible/visual) during a fault condition.

Call the toll free number listed on the back cover of this manual for technical assistance with any of these optional features.

CONTROL BOARD

FUSE - 24 VAC
TRANSFORMER
SECONDARY

HIGH PRESSURE

SWITCH LED

LOW PRESSURE

SWITCH LED

T1 & T2: 24 VAC SUPPLY
M1 & M2: PROVING CIRCUIT
(dry contact)

HOT OUT

GREEN LED

NORMAL

OPERATION

RED LED

FAULT

CONDITION

24 VAC

24 VAC

SUPPLY

PHASE MONITOR

HPWH

3Ø POWER

SUPPLY

COMPRESSOR
OVERLOAD
MODULE

Figure 14

30

WIRING DIAGRAMS

Not all models are factory equipped with Phase Monitors or Compressor Overload Modules. Table 12 shows which models will
include these components from the factory.

TABLE 12

MODEL PHASE

MONITOR

WH-35 No No

WH-55 No No

WH-75 No No

WH-100 Yes No

WH-115 Yes No

WH-140 Yes Yes

WH-170 Yes Yes

Abbreviations are used in the wiring diagrams in this section. Table 13

TABLE 13

ABBREVIATION DESCRIPTION WIRING NOTES

PM Phase Monitor Factory If installed
PC Pump Contactor Factory Load pump if installed
BC Blower Contactor Factory
CC Compressor Contactor Factory
HP High Pressure Switch Factory Indicates high pressure fault
REMHP Remote High Pressure (dry contact) Field Remote fault alert
LP Low Pressure Switch Factory Indicates low pressure fault
REMLP Remote Low Pressure (dry contact) Field Remote fault alert
ON/OFF Remote on/off (dry contact) Field Remote unit on/off capability
OLM Compressor Overload Module Factory If installed, powers overload
DT Terminals for Controller Connection Factory Wired up to the 8 pole connector
RES Remote Reset Field Remote reset after fault

COMPRESSOR

OVERLOAD

MODULE

31

UNIT WIRING DIAGRAMS - FUSE SIZES

208/230 VAC - SINGLE PHASE - 60 HZ

32

: WH-35, WH-55 and WH-75 only.

UNIT WIRING DIAGRAMS - FUSE SIZES

208/230 VAC - THREE PHASE - 60 HZ

33

UNIT WIRING DIAGRAMS - FUSE SIZES

only.

208/230 VAC - THREE PHASE - 60 HZ

34

UNIT WIRING DIAGRAMS - FUSE SIZES

460 VAC - THREE PHASE - 60 HZ

35

UNIT WIRING DIAGRAMS - FUSE SIZES

only.

460 VAC - THREE PHASE - 60 HZ

36

THERMOSTAT AND ACCESSORY WIRING DIAGRAMS

DIGITAL TANK THERMOSTAT WIRING

This Ambient Air Limit Thermostat temporarily disables compressor operation when the return (entering) air temperature is above or
below the normal operating temperature range. The return (entering) air temperature operating range for the HPWH is 50°F to 95°F
(10°C to 35°C).

The heating stage set point is factor set at 95°F (35°C).

When the High Ambient Kit accessory is installed to allow operation at return (entering) air temperatures above 95°F

DIGITAL TANK THERMOSTAT

FULL GAUGE - MODEL MT511Ri

REMOTE TANK
TEMPERATURE
SENSOR

OUTPUT

C

NOTE:
TANK TEMPERATURE
SETTING MUST NOT
EXCEED 140°F (60°C)

121110987654321

NO NC

HPWH

TERMINAL

STRIP

AMBIENT AIR LIMIT THERMOSTAT

CONFIGURATION NOTES:

1) Configure stage 1 for cooling.

2) Configure stage 2 for heating.

3) Set cooling set point at 50°F

4) *Set heating set point 95°F

5) Set cooling differential to 10°F

6) Set heating differential to 5°F

7) Locate remote air temperature
sensor near return (entering) air
connection or inside return air
ducting near unit.

* When High Ambient Air Kit is installed
adjust heating set point to 120°F

(24 VAC HOT)

(24 VAC COM)

RANCO DIGITAL THERMOSTAT

PART # ETC 212000-000

24V COM

OUTPUT 1 OUTPUT 2

NC NO C NC C NO

REMOTE AIR
TEMPERATURE
SENSOR

AMBIENT AIR

LIMIT THERMOSTAT

Figure 15

37

STANDARD TANK THERMOSTAT WIRING

HPWH

TERMINAL

STRIP

(24 VAC HOT)

(24 VAC COM)

NOTE:
TANK TEMPERATURE
SETTING MUST NOT
EXCEED 140°F (60°C)

FIELD SUPPLIED

STANDARD TANK

THERMOSTAT

AMBIENT AIR

LIMIT THERMOSTAT

AMBIENT AIR LIMIT THERMOSTAT
CONFIGURATION NOTES:

1) Configure stage 1 for cooling.

2) Configure stage 2 for heating.

3) Set cooling set point at 50°F

4) *Set heating set point 95°F

5) Set cooling differential to 10°F

6) Set heating differential to 5°F

7) Locate remote air temperature
sensor near return (entering) air
connection or inside return air
ducting near unit.

* When High Ambient Air Kit is installed
adjust heating set point to 120°F

REMOTE AIR
TEMPERATURE
SENSOR

Figure 16

RANCO DIGITAL THERMOSTAT

PART # ETC 212000-000

24V COM

OUTPUT 1 OUTPUT 2

NC NO C NC C NO

38

HIGH AMBIENT AIR KIT WIRING

Note: To purchase High Ambient Air Kit contact your sales representative, distributor or call the toll free technical support number on
the back cover of this manual for further assistance. See Table 14 on page 40 for the part number needed.

DIGITAL TANK THERMOSTAT

NOTE:
TANK TEMPERATURE
SETTING MUST NOT
EXCEED 140°F (60°C)

REMOTE TANK
TEMPERATURE
SENSOR

FULL GAUGE - MODEL MT511Ri

THERMOSTAT TERMINAL STRIP

1 2 3 4 5 6 7 8 9 01 11 21

OUTPUT

C

NO NC

HIGH AMBIENT AIR KIT

1 Phase (COM)

HPWH

TERMINAL

STRIP

4 (Close on rise)

2 (Close on fall)

WHITE (Close)

RED (Close)

BLACK (Close)

DAMPER
PRESSURE
SWITCH

DAMPER
MOTOR
BELIMO

AMBIENT AIR LIMIT THERMOSTAT

CONFIGURATION NOTES:

1) Configure stage 1 for cooling.

2) Configure stage 2 for heating.

3) Set cooling set point at 50°F

4) *Set heating set point 120°F

5) Set cooling differential to 10°F

6) Set heating differential to 5°F

7) Locate remote air temperature
sensor near return (entering) air
connection or inside return air
ducting near unit.

* When High Ambient Air Kit is not installed
adjust heating set point to 95°F

REMOTE AIR
TEMPERATURE
SENSOR

AMBIENT AIR

LIMIT THERMOSTAT

Figure 17

39

RANCO DIGITAL THERMOSTAT

PART # ETC 212000-000

24V COM

OUTPUT 1 OUTPUT 2

NC NO C NC C N O

HIGH AMBIENT AIR KITS

TABLE 14

WH-35 9500012730

WH-55 9500012731

WH-75 9500012732

WH-100

WH-115

WH-140 9500012734

WH-170 9500012735

9500012733

THERMOSTAT AND ACCESSORY WIRING DIAGRAMS

BUILDING RECIRCULATION PUMP WIRING DIAGRAM

CIRCULATING PUMP WIRING DIAGRAM

FOR BUILDING RECIRCULATION TO STORAGE TANK

FIELD SUPPLIED LINE TEMPERATURE CONTROL
INSTALLED IN THE CIRCULATING LOOP RETURN LINE

NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT.

L1 HOT

L2 NEUTRAL

120 VAC

POWER

CIRC

PUMP

MOTOR

Figure 18

40

thermostat. See Figure 18 on page 40 for wiring.

5. See Water Connections on page 17.

6. If a building recirculation loop is present the circulation pump must be controlled by a

4. See Closed Systems and Thermal Expansion on page 13

FULL PORT BALL VALVE

CHECK VALVE

LEGEND

TEMPERATURE & PRESSURE

RELIEF VALVE

PRESSURE RELIEF VALVE

DRAIN

TEMPERATURE GAGE

TANK OR LINE TEMPERATURE

CONTROL

CIRCULATING PUMP

BUILDING

LINE THERMOSTAT

WYE STRAINER

PREHEATED

HEAT TRAP PIPING

MINIMUM 18 INCHES

RECIRCULATION

LOOP RETURN

HOT WATER

OUT TO

FIXTURES

WATER OUT

PIPE T&P TO

BACKUP

TANK

THERMOSTAT

OPEN DRAIN

WATER

HEATER

COLD

WATER

SUPPLY

EXPANSION

TANK

TO THE STORAGE TANK ON PREHEAT

IMPORTANT INSTALLATION NOTES:

1. COLD WATER SUPPLY MUST CONNECT

PIPING CONFIGURATION AND OTHER DEVICES;

ONE AIR TO WATER HEAT PUMP, SINGLE TEMPERATURE, PREHEAT SYSTEM

WITH VERTICAL STORAGE TANK AND BACKUP WATER HEATER

3. See Temperature - Pressure Relief Valve on page 14.

WATER PIPING DIAGRAMS

Before installation of water piping review the following:

2. See Water Temperature on page 10.

1. See Mixing Valves on page 13.

WARNING: THIS DRAWING SHOWS SUGGESTED

WITH FORCED BUILDING RECIRCULATION

SYSTEMS

2. BUILDING RECIRCULATION LOOP

RETURN LINE MUST CONNECT TO THE

INLET OF THE BACKUP WATER HEATER

ON PREHEAT SYSTEMS.

CHECK WITH LOCAL CODES AND ORDINANCES

FOR ADDITIONAL REQUIREMENTS.

41

PIPE T&P TO

OPEN DRAIN

VALVE

FLUSH

PURGE &

HPWH

STORAGE

WATER

(OUTLET)

SUPPLY

TANK

RETURN

WATER

(INLET)

VALVE

FLUSH

DRAIN &

SUPPLY

FOR HPWH MODELS

FIELD SUPPLIED PUMP

WITHOUT FACTORY PUMP

FINISHED

FLOOR

FULL PORT BALL VALVE

CHECK VALVE

DRAIN

TEMPERATURE GAGE

LEGEND

thermostat. See Figure 18 on page 40 for wiring.

5. See Water Connections on page 17.

6. If a building recirculation loop is present the circulation pump must be controlled by a

4. See Closed Systems and Thermal Expansion on page 13

NOTE:

CONNECT BUILDING

RECIRC RETURN TO

INLET OF BACKUP

WATER HEATER

WHEN PRESENT

COLD WATER

SUPPLY

EXPANSION

TANK

BUILDING

RECIRCULATION

LOOP RETURN

LINE THERMOSTAT

WYE STRAINER

TANK OR LINE TEMPERATURE

TEMPERATURE & PRESSURE

RELIEF VALVE

PRESSURE RELIEF VALVE

CONTROL

CIRCULATING PUMP

TANK THERMOSTAT

TANK

STORAGE

PIPING CONFIGURATION AND OTHER DEVICES;

ONE AIR TO WATER HEAT PUMP, SINGLE TEMPERATURE

WITH VERTICAL STORAGE TANK

3. See Temperature - Pressure Relief Valve on page 14.

WATER PIPING DIAGRAMS

2. See Water Temperature on page 10.

Before installation of water piping review the following:

1. See Mixing Valves on page 13.

WARNING: THIS DRAWING SHOWS SUGGESTED

WITH FORCED BUILDING RECIRCULATION

HOT OUTLET

WATER HEATER

TO FIXTURES OR

INLET OF BACKUP

PIPE T&P TO

OPEN DRAIN

FLUSH

PURGE &

CHECK WITH LOCAL CODES AND ORDINANCES

FOR ADDITIONAL REQUIREMENTS.

42

VALVE

SUPPLY

HPWH

WATER

(OUTLET)

(INLET)

WATER

RETURN

VALVE

FLUSH

DRAIN &

SUPPLY

FOR HPWH MODELS

FIELD SUPPLIED PUMP

WITHOUT FACTORY PUMP

FINISHED

FLOOR

NOTE:

CONNECT BUILDING

BUILDING

RECIRC RETURN TO

RECIRCULATION

LOOP RETURN

WHEN PRESENT

INLET OF BACKUP

WATER HEATER

LEGEND

thermostat. See Figure 18 on page 40 for wiring.

5. See Water Connections on page 17.

6. If a building recirculation loop is present the circulation pump must be controlled by a

4. See Closed Systems and Thermal Expansion on page 13

FULL PORT BALL VALVE

TEMPERATURE & PRESSURE

RELIEF VALVE

CHECK VALVE

PRESSURE RELIEF VALVE

TEMPERATURE GAGE

CIRCULATING PUMP

DRAIN

WYE STRAINER

TANK OR LINE TEMPERATURE

CONTROL

HOT OUTLET

WATER HEATER

TO FIXTURES OR

INLET OF BACKUP

LINE THERMOSTAT

TANK THERMOSTAT

TANK

STORAGE

COLD WATER

SUPPLY

EXPANSION

TANK

TWO AIR TO WATER HEAT PUMPS, SINGLE TEMPERATURE

WITH VERTICAL STORAGE TANK

3. See Temperature - Pressure Relief Valve on page 14.

WATER PIPING DIAGRAMS

2. See Water Temperature on page 10.

Before installation of water piping review the following:

1. See Mixing Valves on page 13.

WITH FORCED BUILDING RECIRCULATION

PIPE T&P TO

OPEN DRAIN

VALVE

PURGE

WATER

(OUTLET)

SUPPLY

PIPING CONFIGURATION AND OTHER DEVICES;

WARNING: THIS DRAWING SHOWS SUGGESTED

CHECK WITH LOCAL CODES AND ORDINANCES

FOR ADDITIONAL REQUIREMENTS.

43

HPWHHPWH

FLUSH

VALVES

FLUSH

VALVES

DRAIN &

(INLET)

WATER

RETURN

SUPPLY

FOR HPWH MODELS

FIELD SUPPLIED PUMP

WITHOUT FACTORY PUMP

FINISHED

FLOOR

thermostat. See Figure 18 on page 40 for wiring.

5. See Water Connections on page 17.

6. If a building recirculation loop is present the circulation pump must be controlled by a

4. See Closed Systems and Thermal Expansion on page 13

FULL PORT BALL VALVE

CHECK VALVE

LEGEND

TEMPERATURE & PRESSURE

RELIEF VALVE

PRESSURE RELIEF VALVE

DRAIN

TEMPERATURE GAGE

TANK OR LINE TEMPERATURE

CIRCULATING PUMP

WYE STRAINER

CONTROL

BUILDING

RECIRCULATION

LOOP RETURN

LINE THERMOSTAT

NOTE:

CONNECT BUILDING

RECIRC RETURN TO

TANK THERMOSTAT

WHEN PRESENT

INLET OF BACKUP

WATER HEATER

COLD WATER

SUPPLY

EXPANSION

TANK

WITH FORCED BUILDING RECIRCULATION

ONE AIR TO WATER HEAT PUMP, SINGLE TEMPERATURE

WITH HORIZONTAL STORAGE TANK

3. See Temperature - Pressure Relief Valve on page 14.

WATER PIPING DIAGRAMS

2. See Water Temperature on page 10.

Before installation of water piping review the following:

1. See Mixing Valves on page 13.

HOT OUTLET

TO FIXTURES OR

VALVE

FLUSH

PURGE &

HPWH

WARNING: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND OTHER DEVICES;

CHECK WITH LOCAL CODES AND ORDINANCES

FOR ADDITIONAL REQUIREMENTS.

44

WATER HEATER

INLET OF BACKUP

SUPPLY

WATER

(OUTLET)

(INLET)

WATER

RETURN

TANK

STORAGE

VALVE

FLUSH

DRAIN &

SUPPLY

FOR HPWH MODELS

FIELD SUPPLIED PUMP

WITHOUT FACTORY PUMP

CHECK VALVE

FULL PORT BALL VALVE

LEGEND

TEMPERATURE & PRESSURE

RELIEF VALVE

PRESSURE RELIEF VALVE

DRAIN

TEMPERATURE GAGE

TANK OR LINE TEMPERATURE

CONTROL

CIRCULATING PUMP

WYE STRAINER

BUILDING

RECIRCULATION

LOOP RETURN

LINE THERMOSTAT

NOTE:

CONNECT BUILDING

TANK THERMOSTAT

RECIRC RETURN TO

INLET OF BACKUP

WATER HEATER

WHEN PRESENT

COLD WATER

SUPPLY

EXPANSION

TANK

thermostat. See Figure 18 on page 40 for wiring.

5. See Water Connections on page 17.

6. If a building recirculation loop is present the circulation pump must be controlled by a

4. See Closed Systems and Thermal Expansion on page 13

VALVE

PURGE

HOT OUTLET

WATER HEATER

TO FIXTURES OR

INLET OF BACKUP

WATER

(OUTLET)

SUPPLY

HPWHHPWH

PIPE T&P TO

OPEN DRAIN

FLUSH

VALVES

TANK

STORAGE

SUPPLY

RETURN

WATER

(INLET)

FINISHED

FLOOR

3. See Temperature - Pressure Relief Valve on page 14.

WATER PIPING DIAGRAMS

2. See Water Temperature on page 10.

Before installation of water piping review the following:

1. See Mixing Valves on page 13.

TWO AIR TO WATER HEAT PUMPS, SINGLE TEMPERATURE

WITH HORIZONTAL STORAGE TANK

WITH FORCED BUILDING RECIRCULATION

WARNING: THIS DRAWING SHOWS SUGGESTED

PIPING CONFIGURATION AND OTHER DEVICES;

CHECK WITH LOCAL CODES AND ORDINANCES

FOR ADDITIONAL REQUIREMENTS.

45

FLUSH

VALVES

DRAIN &

LIMITED WARRANTY

MODELS AWH, WH, WW, CPH COMMERCIAL HEAT PUMP WATER HEATERS

A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this commercial heat pump water heater subject
to the terms, conditions and disclaimers stated below:

1. COMPRESSOR

If within FIVE (5) years after initial installation of this heat pump water heater the compressor shall prove upon examination by the warrantor to
be defective, the warrantor will provide a replacement compressor.

2. ALL OTHER PARTS

If within ONE (1) year after initial installation of this heat pump water heater any other part or portion shall prove upon examination by the
warrantor to be defective in material or workmanship, the warrantor will repair or replace such part or portion at its option. This warranty also
extends to any factory supplied accessories.

3. CONDITIONS AND EXCEPTIONS

Refrigerant, lters, refrigerant driers, and fan belts are not covered under this limited warranty. The warranty on all replacement parts, including
the compressor, will be limited to the unexpired term of the original warranty. This warranty shall apply only when the heat pump water heater
is installed in accordance with local plumbing and building codes, ordinances and regulations, the printed instructions provided with it and good
industry practices.

a. This warranty shall apply only when the unit is:

(1) used at temperatures not exceeding the maximum system temperatures printed in the instructions provided;

(2) lled with potable water, free to circulate at all times and free of damaging water sediment or scale deposits;

(3) used in a non-corrosive and not contaminated atmosphere;

(4) in its original installation location,

(5) in the United States, its territories or possessions, and Canada;

(6) sized in accordance with proper sizing techniques for commercial heat pump water heaters;

(7) bearing the original rating label which has not been altered, defaced or removed, except as required by the warrantor;

(8) used in an open water system or in a closed system with a properly sized and installed thermal expansion tank;

(9) energized at the proper voltage and phase as stated on the rating label;

(10) maintained in accordance with the instructions printed in the manual included with the heat pump water heater;

b. Any accident to the water heater, any misuse, abuse (including freezing) or alteration of it, any operation of it in a modied
form, will void this warranty.

4. SERVICE REPAIR AND EXPENSE

Under this limited warranty the warrantor will provide only a replacement heat pump water heater or part thereof. The owner is responsible for all
other costs. Such costs may include but are not limited to:

a. Labor charges for service, removal, repair, or reinstallation of the water heater or any component part;

b. Shipping, delivery, handling, and administrative charges for forwarding the new heater or replacement part from the nearest

distributor and returning the claimed defective heater or part to such distributor;

c. All cost necessary or incidental for any materials and/or permits required for installation of the replacement heater or part.

5. LIMITATIONS ON IMPLIED WARRANTIES

Implied warranties, including any warranty of merchantability imposed on the sale of this heater under state law are limited to one (1) year dura­tion for the heater or any of its parts. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not
apply to you.

6. CLAIM PROCEDURE

Any claim under this warranty should be initiated with the dealer who sold the heater, or with any other dealer handling the
warrantor’s products. If this is not practicable, the owner should contact:

U.S. Customers Canadian Customers
A. O. Smith Water Products Company A. O. Smith Enterprises, Ltd.
500 Tennessee Waltz Parkway P. O. Box 310- 768 Erie Street
Ashland City, TN 37015 Stratford, Ontario N5A 6T3
Telephone: [phone] Telephone: [phone]

a. The warrantor will only honor replacement with identical or similar water heater or parts thereof which are manufacture
or distributed by the warrantor.
b. Dealer replacements are made subject to in-warranty validation by warrantor.

7. DISCLAIMERS

NO OTHER EXPRESS WARRANTY HAS BEEN OR WILL BE MADE IN BEHALF OF THE WARRANTOR WITH RESPECT TO THE MERCHANTABILITY
OF THE HEATER OR THE INSTALLATION, OPERATION, REPAIR, OR REPLACEMENT OF THE HEATER. THE WARRANTOR SHALL NOT BE
RESPONSIBLE FOR WATER DAMAGE, LOSS OF USE OF THE UNIT, INCONVENIENCE, LOSS OR DAMAGE TO PERSONAL PROPERTY, OR
OTHER CONSEQUENTIAL DAMAGE. THE WARRANTOR SHALL NOT BE LIABLE BY VIRTUE OF THIS WARRANTY OR OTHERWISE FOR
DAMAGE TO ANY PERSONS OR PROPERTY, WHETHER DIRECT OR INDIRECT, AND WHETHER ARISING IN CONTRACT OR IN TORT.
a. Some states do not allow the exclusion or limitation of the incidental or consequential damage, so the above limitation or
exclusion may not apply to you.
b. This warranty gives you specic legal rights, and you may also have other rights which vary from state to state.

46

Fill in the following for your own reference. Keep it. Registration is not a condition of warranty. The model and serial number are found
on the heater’s rating label.

Model No. Serial No. Date Installed

Dealer’s Name

Dealer’s Address Phone No.

City and State Zip

47

Technical Support: 800-527-1953 • Parts: 800-433-2545 • Fax: [phone]

500 Tennessee Waltz Parkway, Ashland City, TN 37015

www.hotwater.com