Rheem 310 Series Operating instructions

This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
R
Rh he ee em m A Au us st tr ra al li ia a P Pt ty y L Lt td d
A AB BN N 2 21 1 0 09 98 8 8 82 23 3 5 51 11 1
SERVICE INSTRUCTIONS
310 Series Heat Pump
TM025
R
R
Re
e
ev
v
vi
i
is
s
si
i
io
o
on
n
n:
:
: B
B
B
P
P
Pu
u
ub
b
bl
l
li
i
is
s
sh
h
he
e
ed
d
d:
:
: 0
0
08
8
8/
/
/0
0
07
7
7
551310

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
1
Contents
Safety Warning....................................................................................................................2
Introduction..........................................................................................................................2
Specifications.......................................................................................................................3
Preventative Maintenance ...................................................................................................3
Operation.............................................................................................................................4
Electronic Controller ............................................................................................................5
Operating Sequence Flow Charts:.......................................................................................6
Refrigeration Terms and their Meaning................................................................................8
Components and their Function...........................................................................................8
Common Faults ...................................................................................................................9
Wiring Diagram..................................................................................................................11
Refrigeration Sealed System Diagram...............................................................................12
LED Indication ...................................................................................................................12
Fault Finding......................................................................................................................14
Refrigerant Charge ............................................................................................................45
Electrical Insulation Testing...............................................................................................46
Component Replacement Procedures – Water Heater......................................................47
Component Replacement Procedures – Refrigeration Plant .............................................52
Component Replacement Procedures – Sealed Refrigeration System .............................57
Exploded View - Refrigeration Plant..................................................................................62
Replacement Parts List – Refrigeration Plant.................................................................63
Exploded View - Water Heater...........................................................................................64
Replacement Parts List – Water Heater.........................................................................65
Rheem Electric Water Heater Warranty - (Australia Only).................................................66
Document Revision History................................................................................................67

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
2
Safety Warning
The purpose of this Service Manual is to provide sufficient information to allow a person
with the skills as required by the controlling Regulatory Authorities to carry out effective
repairs to a Rheem 310 series Heat Pump Water Heater in the minimum of time.
Safety precautions or areas where extra care should be observed when conducting tests
outlined in this manual are indicated by print in bold italics and/or a warning symbol. Take
care to observe the recommended procedure.
Certain diagnostic procedures outlined in these service instructions require
“live” testing to be conducted. Wear Personal Protective Equipment (PPE)
when conducting these tests to prevent the risk of electric shock. (Refer to
the Rheem Safety Procedure on electrical testing)
R134A is a controlled substance under the fair trading act. Personnel
qualified and licensed to work with refrigerants may only carry out service
and repair to the sealed refrigeration system. During repair the refrigerant
must be recovered, not vented to atmosphere.
Environmental
At the end of the service life of a Rheem heat pump the refrigerant must be
recovered by personnel qualified and licensed to work with refrigerants
prior to the unit being disposed of. Refrigerants must not be vented to
atmosphere.
Introduction
The information provided in these instructions is based on the water heater being installed
in accordance with the Installation Instructions provided with each water heater.
Should you require further technical advice on a Rheem 310 Series Heat Pump Water
Heater, contact your nearest Rheem Service Department where all genuine replacement
parts are also available.
Heater Model Identification
All identification numbers are designed to convey detailed information about the water
heater to which it is attached. The model number consists of 8 digits.
5 X X 310 0 X
5 – Renewable Energy Model
5 – Air Sourced
9 – Solar Sourced
0 – No Heating Units
1 – Booster Element
Storage Capacity in Litres
No Reference – System Requirement
0 – Element Not fitted
5 – 2400 watts
7 – 3600 watts
Note: Model number, serial number and date of manufacture should be quoted in all
correspondence.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
3
Specifications
Water Heater
Model 551310
Capacity - Litres 310
Boost Capacity - Litres 220
Booster element rating - kW 2.4 or 3.6
T&PR valve Rating - kPa 1000
With ECV 680
Maximum inlet pressure - kPa Without ECV 800
Inlet / Outlet RP¾/20
Water Connections T&PR RP½/15
Quantity 1
Anode Length 1153
Control board thermostat setting (fixed) 60ºC
Limp mode mechanical thermostat setting 70ºC
Mechanical thermostat ECO setting 88ºC
Refrigeration System
Parameter 551310
Sound rating 51 dBA @1.5m
Superheat setting (Factory) +6ºC at 10ºC Evaporator temp.
Refrigerant charge R134A 1050 grams
Compressor internal OTC Open 150ºC. Close 90ºC (automatic reset)
Compressor winding resistance Run winding - Red & Blue: 2.2 ohms at 20ºC
Start winding - Red & Black: 3.27 ohms at 20ºC
Compressor Capacitor 35µF 240 VAC 50HZ
Fan winding resistance Run winding – Black & Brown: 184 ohms at 20ºC
Start winding – Black & Blue: 238 ohms at 20ºC
Fan Capacitor 2µF 240 VAC 50HZ
Circulator winding resistance 75.3 ohms @ 20ºC
Preventative Maintenance
It is suggested for peak performance that the water heater be serviced annually.
1. Check for discharge from the T&PR valve. When the element or heat pump is
operating a small discharge of water may be evident. Operate the valve-easing lever to
ensure the valve opens and resets properly. Always open and close the valve gently.
The T&PR valve should be replaced at 5 yearly intervals.
2. Check for leaks at all cylinder fittings.
3. Check for signs of excessive corrosion on the water heater jacket.
4. Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
5. Conduct an 'Electrical insulation test' on the water heater (refer to page 46).
6. Check evaporator fins and fan blade for build up of dust or debris.
7. Check for sludge build up and if necessary drain and flush tank.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
4
Operation
Operation – Water System:
The heat pump utilises a form of heating called ‘top down’ heating.
The circulator (1) draws cooler water from the bottom of the cylinder
via the long dropper tube (2). The water passes through the heat
exchanger (condenser) (3) where it is heated by the refrigerant and is
then returned to the top of the cylinder via a short dropper tube (4).
Operation – Heat Pump Mode:
During normal operation in ‘heat pump’ mode the electronic controller
(control board) holds a control relay in the energised state and power
for the compressor is passed to an electronic switch (called a triac) via
the normally open relay contact.
The operation of the compressor causes a pressure difference within
the sealed refrigeration system. This pressure difference causes the
refrigerant to move around the sealed system. The refrigerant enters
the evaporator (5) as a liquid, as the refrigerant absorbs heat from the
atmosphere it changes state, at low pressure, from a sub cooled liquid
to a super heated vapour or gas (evaporates). The vapour then enters
the compressor (6) and obtains more heat, known as heat of
compression, and passes into the heat exchanger as a super heated
vapour at high pressure.
As the refrigerant passes through the heat exchanger it gives off
heat which is absorbed by the water flowing through a separate
chamber inside the heat exchanger. As the refrigerant gives off
heat it cools and changes state back into a liquid (condenses). The
refrigerant then enters the evaporator again and the cycle is
repeated.
Operation – Boost Mode:
The controller will enter ‘boost’ mode when atmospheric conditions are unsuitable for heat
pump operation or a possible failure of the refrigeration or water circuits has been
detected. The following error conditions will initiate boost mode:
1. The temperature sensed by the ambient air sensor is below 0°C.
2. The water leaving the heat exchanger is greater than 80°C.
3. The compressor discharge temperature is greater than 110°C.
4. The evaporator temperature is less than -3°C.
5. The failure of sensors S3, S4 or S5.
6. The compressor is not running based on either of the following conditions:
a. After 2 minutes in controller sequence 3 the compressor discharge temperature has
not risen 15°C above ambient.
b. In controller sequence 4 the water temperature rise across the heat exchanger
(condenser) is less than 8°C.
In boost mode the electronic controller continues to control the temperature of the water in
the cylinder and the circulator however the control relay is de-energised switching the
power supply from the compressor triac to the element.
1
2
3
4
3
6
5

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
5
Boost mode allows 220 litres of 60ºC hot water to be provided by electric boosting. During
this mode the circulator will cycle on and off periodically allowing for the 220 litre boost
capacity rather than just the amount of water above the element as is the case with a
conventional electric boost system.
Once a heating cycle is completed the error is cleared and normal operation is resumed on
the next call for heat.
Note: If sensor S4 fails the system will operate on boost mode however the temperature
will in this case be controlled by the mechanical thermostat and 220 litres of 70ºC water
will be available.
Operation – Limp Mode:
Limp mode will only occur due to the failure of both sensors S1 and S4.
In limp mode the electronic controller no longer controls the operation of the heat pump
and both ‘heat pump’ mode and ‘boost’ mode are rendered inoperable. The control relay is
de-energised switching the power supply from the compressor triac to the element.
Limp mode allows 111 litres of hot water to be provided by electric boosting and the water
temperature is controlled by the mechanical thermostat which is set to 70°C; in this
condition only the water in the zone above the element is heated as the circulator does not
operate.
It should be noted that if sensor S1 fails and sensor S4 is operational the system operates
in boost mode however the circulator cannot operate. In this case the end result is an
operation similar to limp mode in which 111 litres of water is heated by the booster and the
temperature controlled to 70ºC by the Robertshaw thermostat.
Electronic Controller
The main features of the electronic controller
(control board) are shown on the diagram opposite.
The inputs to the software are shown in blue and
the outputs that control the heat pump are shown in
red.
The connection marked “relay element” energises
or de-energises a relay that switches from heat
pump heating to electric element heating when the
system operates in “boost” or “limp” mode.
The “Compressor TRIAC” switches the power to the
compressor on and off.
The “Communication port” can be used in
conjunction with a computer to read the inputs and
outputs from the software. This information may be
logged using specially designed logging software
(Contact Rheem Service for more information
regarding this software).
The “Software loading port” is only used for loading
software on to the control board.
The green and red LED’s indicate the condition of
the heat pump (refer to the section titled “LED
Indication” on page 12).

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
6
Operating Sequence Flow Charts:
Page 1 of 2:
Power to controller
Tank
sensors S3-S5
ok? NO
YES
YES
NO
Heat
pump sensors
T0-T4 ok?
Sequence 0
S4< 44.5°C
or S3 < 50°C
YES
Call for heat
Green LED solid
System in stand by mode
NO
Set paramaters
Seq 1
Circulator on
Seq 2
Compressor on
Evaporator fan on 30 seconds later
Circulator to minimum flow rate
Sequence 3
T0
= or > than
57°C?
Cylinder sensors
Heat exchanger
outlet sensor
NO
Sequence 4
Circulator to variable speed
YES
Use value of T4 and T1 to set circulator flow
rate to achieve 62°C at heat exchanger outlet
T0
= 60°C?
Fault
detected?
S4 > 53°C
or S5 > 50°C?
T4
<0°C?
YES
Green LED flashing
At maximum flow rate
Circulator off
Compressor off
Evaporator off
NO
Refrigeration
Heating cycle
ends
Adjust pump
flow rate
NO
T4 < 0°CT0 > 80°C T2 < -3°C
Water
discharge temp
too hot
T0 - T1
<8°C
Refrigerant
circuit not
operational
NO
Temperature rise across heat
exchanger smaller than 8°C
Ambient air
temp too
low Evaporator
frozen
Sensor
T0 - T4
Open or
short circuit
T3 >
T4 +15°C?
After 2 minutes
YES
NO
Compressor discharge
temperature 15°C above ambient
Condenser inlet
temp higher than
pick up temp
T1 > S4 +7°C T3 > 110°C
High ambient
temp or running
too long
Check every
11 minutes
NO
Compressor
recently on -
delay start
S3 - S5
H
Y
Z
Open or
short circuit
Thermostat
contacts
closed?
NO
T2
<-3°C?
T0
>80°C? NO
YES
Ambient conditions too cold
for heat pump operation
Circulator
fault
Controller de-energised
no operation
NO
Error condition reset
Relay energised
NO
YES
H
T3
>60°C?
YES
YES
A
H
T3 >
T4 +15°C?
YES
NO
Compressor discharge
temperature 15°C above ambient
YES
Software
version
HPV 4.0
or higher
HPV 3.1, HPV
3.2 or no HPV
identification
Relay de-
energised &
element on
S0 & S1
> 62°C?
YES
YES
NO S0 & S1
< 62°C? YES
Relay
energised &
element off
S4< 44.5°C
or S3 < 50°C
NO
B
NO
YES
B
YES
NO
YES

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
7
Page 2 of 2:
NO
Boost Mode
220L heated to
approx. 60°C
H
Relay de-energised
Red LED Flashing
Element On
S1
>62°C? S4 >53°C?
YES
NO
Element Off
YES
Z
Circulator On
NO
S1
<61°C?
NO
S4
>53°C?
YES Circulator Off
YES
NO
Sequence 0
YES
S4
Sensor
ok?
Temp at
thermostat =
70°C?
Controller can no longer detect
lower cylinder temperature.
Water temperature will be
controlled by mechanical
thermostat to 70°C
S1
Sensor
ok?
NO
YES
Controller can no longer detect
upper cylinder temperature.
The circulator will not operate
preventing water below the
element level from heating
Temperature at sensor S4 will
not achieve 53°C
NO
Heating Cycle
complete
Element On
Limp Mode
111L heated to
approx. 70°C
NO
Element Off
YES
Power to controller off Y
S1
Sensor
ok?
S1
>62°C?
YES
Boost Mode
220L heated to
approx. 70°C
Circulator On
Temp at
thermostat =
70°C?
YES
S1
<61°C?
NO
Circulator Off
YES
NO
YES
Element On
NO
T2
> 2°C?
T4
> 2°C? A
YES
NO
NO Ambient temperature high enough
to resume heat pump operation
YES

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
8
Refrigeration Terms and their Meaning
Sub Cooled Liquid – A substance below its saturation temperature at a given pressure.
Super Heated Vapour –A substance above its boiling point at a given pressure.
Saturated Vapour – A substance at its boiling point at a given pressure.
Latent Heat – Hidden (invisible) heat removed or added to a substance that results in a
change of state (i.e. liquid to a vapour) without an increase or decrease in temperature.
Heat of Compression – The additional heat added to a substance by the act of
compressing it.
Low Side – Components and pipe work of a refrigeration system operating at low
pressure, generally considered to be the evaporator, suction line and accumulator.
High Side – Components and pipe work of a refrigeration system operating at high
pressure, generally considered to be the condenser, discharge line, liquid receiver/filter
drier and compressor case where a rotary compressor is utilized.
Boil Off – The action of a substance as it absorbs heat and changes state (evaporates)
from a liquid to a vapour (gas).
Give Up Heat – The action of a substance as it releases heat and changes state
(condenses) from a vapour (gas) to a liquid.
Components and their Function
Temperature and Pressure Relief Valve - A valve designed to provide automatic relief by
discharging water in case of excessive temperature, pressure or both.
Never fit a T&PR Valve with a pressure rating greater than that indicated on
the product-rating label.
Pressure Limiting Valve (P.L.V.) - A valve that controls its outlet pressure to a
predetermined limit.
Outlet Delivery Tube (Dip Tube) - A plastic tube installed in the hot water outlet of the
water heater cylinder to conduct water from the highest point to the outlet connection. It
also acts as a fitting liner.
Diffuser - A plastic device installed in the cold water inlet of the water heater cylinder to
assist with stratification. It also acts as a fitting liner.
Fitting Liner - A plastic tube installed in the cold-water inlet of the water heater to provide
protection against corrosion through the life of the water heater.
Anode (Sacrificial) - A metal alloy electrode installed in the water heater cylinder that by
galvanic action protects the cylinder from corrosion.
Thermostat - A device responsive to temperature that controls the supply of electrical
energy to the compressor, which results in the stored water being maintained at the
required temperature.
Evaporator Thermistor - A device responsive to temperature that controls the active
supply between the compressor circuit and the booster element circuit.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
9
Compressor - An electro-mechanical device that adds heats to the refrigerant by
compressing it, known as “heat of compression” the resulting increase in refrigerant
temperature increases its pressure and causes the refrigerant to circulate through the
system.
Evaporator - A finned copper coil mounted on top of the water heater. The refrigerant
enters as a liquid, as it passes through the coil it absorbs heat from the surrounding
atmosphere and “boils off” (evaporates) to a gas.
Condenser - An insulated housing containing stainless steel chambers where heat
transfer occurs. The condenser (or heat exchanger) contains three chambers, one for
refrigerant, one for water and a third separating chamber containing air. The refrigerant
enters as a gas, as it passes through the condenser it transfers (“gives up”) the heat
absorbed via the evaporator to the water flowing through the condenser in a separate
chamber, during this process the refrigerant cools and changes state (condenses) back to
a liquid.
Receiver Filter Drier - This device, fitted between the condenser and thermal expansion
(TX) valve, receives and stores liquid refrigerant from the condenser for delivery to the
evaporator. The receiver also incorporates a filter and drier to trap impurities and remove
moisture from the sealed refrigeration system
Accumulator - This device, fitted in the suction line prior to the compressor, is designed to
accumulate and prevent liquid refrigerant from entering and damaging the compressor.
Any liquid refrigerant is evaporated or “boiled off” and converted to a vapour by the
accumulator.
Thermal Expansion (TX) Valve -A valve, installed between the condenser and
evaporator that controls (meters) the amount of refrigerant delivered to the evaporator.
The TX valve has an external temperature sensor fitted to the suction line and increases or
decreases the refrigerant flow to the evaporator depending on the detected suction line
temperature.
Thermal Cut Out (Overload) - A manual reset temperature sensitive device that
automatically cuts off the supply of electrical energy to the control board and/or boost
element.
Heating Unit (Element) - A tubular device containing an electric resistance element that
converts electrical energy to heat. Standard element ratings are 2.4 and 3.6kW.
Common Faults
When a complaint is lodged about the performance of a hot water system there are a
number of causes that should be checked and eliminated. In an attempt to pinpoint the
most likely cause it is important to discuss with the customer their reasons for the
complaint, the duration of the problem, any change in circumstances or usage and recent
weather conditions. This information in conjunction with the following listed common
complaints will assist you in locating the most likely cause. All procedures assume there is
water flowing through the water heater.
Discoloured water - This may be the result of discoloured water entering from the cold
water mains. Check if the cold water is also discoloured.
Excessive hot water usage - The complaints of insufficient hot water and no hot water
can on many occasions be attributed to hot water usage exceeding the capacity of the
water heater to provide hot water.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
10
When first attending a call of this nature it is essential to establish the probable hot water
usage by querying the usage habits of the household and compare this with the potential
delivery of the model water heater installed. It can then be established if the usage is
within or outside the capacity of the model. The areas to look at for excessive usage are:
1. Automatic washing machines.
2. Showers exceeding 12 litres/minute for mixed water and 5 minutes in duration.
3. Two or more showers operating at the same time.
4. Change of occupancy or number of persons increased.
5. High water pressure area. (Excessive pressure relief valve discharge)
6. Plumbing leaks.
7. Crossed connection.
Water hammer - A water heater will not cause water hammer, however valves associated
with the water heater may be the source of the problem i.e. cold-water stopcock, non-
return valve or relief valve.
Most water hammer problems are associated with plumbing, hot and cold or appliances
i.e. solenoid valves, ballcocks, loose pipes, sharp angles in pipe work, faulty or worn valve
parts, loose tap washers or neighbouring equipment.
High water pressure areas will have more complaints of this nature and the use of a
pressure-limiting valve (PLV) to reduce the household cold-water pressure will usually
solve most problems.
Hot water plumbing leaks - If hot water has not been used for a period of time, feeling
the temperature of the hot water line may give an indication of water flow if the pipe is
warm. The method of checking for plumbing leaks is:
1. Turn off the stopcock on the cold water supply to the water heater.
2. Open a hot tap to ensure the flow of water stops. This will confirm the stopcock is
operating correctly.
3. Turn off the hot tap.
4. Turn on the stopcock to make up the water pressure in the cylinder, and then turn the
stopcock off again.
5. Wait approximately 5 minutes then do either of the following:
a. With your ear close to the stopcock turn it on slightly and listen for any water
passing. If there are no leaks, water should not pass.
b. Open a hot tap while listening for any pressure release. If there is a pressure
release there will be no leaks in the plumbing system.
Mixing or crossed connections - If an automatic dishwasher, washing machine, flick
mixer tap, tempering valve or thermostatic mixing valve is installed there is always the
possibility that the cold water could mix with the hot water through a faulty or incorrectly
installed valve. This is referred to as a cross connection. The complaints of insufficient hot
water, water too cold or excessive discharge from the pressure relief valve may be
attributed to a cross connection. The method of checking for a cross connection is:
1. Turn off the stopcock on the cold water supply to the water heater.
2. Open a hot tap. If water flow is persistent and cold a cross connection exists.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
11
Wiring Diagram

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
12
Refrigeration Sealed System Diagram
LED Indication
All 310 series Heat Pumps have LED indication. There are two variations of LED indication
depending upon the version of the controllers software; however all versions utilise a red
and green LED to display the operational status and/or fault condition of the appliance.
Note: The software version is printed on a label on the control board.
Controller Software Version HPV 3.1, HPV 3.2 or no HPV identification
310 Series Heat Pumps with controller version HPV3.1, HPV 3.2 or no HPV identification
have a green and red LED located internally on the control board in the heat pump
(refrigeration) module and utilise the following LED indication:
LED Indication
LED Status Condition Details
Green Solid S4 > 53ºC or S5 > 50ºC Standby mode (end of heating cycle,
cylinder water at required temperature).
Green Flashing S4 < 44.5ºC or S3 < 50ºC Call for heat initiated.
Red Flashing Various (refer to operating sequence flow chart on
page 6 for more details).
Component fault or ambient conditions
too cold for heat pump operation.
No indication Fault or system operating
in limp mode.
Fault or system in limp mode with call for
heat satisfied (water in cylinder @ 70ºC
determined by mechanical thermostat).
Note: Refer to diagram on page 5 for control board LED location.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
13
Controller Software Version HPV 4.0 or higher
310 series Heat Pumps with controller version HPV 4.0 or higher have a red and green
LED located externally on the front of the heat pump module or internally on the control
board in the heat pump (refrigeration) module depending upon date of manufacture.
LED Flashing Frequency: Different combinations of flashing red and/or green LED’s are
utilised to indicate the operational status or fault condition of the Heat Pump. Each flash in
a series will last 0.5 seconds and is separated by 0.5 seconds between flashes. Each
series of flashes is separated by 2 sec.
Example: LED provides 2 flashes: 1) LED on for 0.5 sec.
2) LED off for 0.5 sec.
3) LED on for 0.5 sec.
4) LED off for 2 sec.
5) Return to Step 1).
Operational LED Indication: If no fault is present the green LED will flash as shown
below to indicate the operational sequence number the Heat Pump is currently operating
in (refer to operating sequence flow chart on page 6 for more details).
Operational LED Indication
Sequence Green LED Red LED
0 Solid 0
2 2 flashes 0
3 3 flashes 0
4 4 flashes 0
Fault Indication: If a fault is present the green and/or red LED’s will indicate the fault
condition according to the table below.
Fault Indication
Fault Error Green LED Red LED
Faulty power supply or system in limp mode
with call for heat satisfied (1) N/A 0 0
T3 (comp dis) > 60°C in sequence 0(2) SerrNo 4 1 Flash 0
T4 (ambient air) < 0°C (3) SerrNo 1 0 Solid
Any Sensor Strip Sensor Fault Any Sflag 0 1 Flash
Water circ fault T0 (water outlet) > 80°C SerrNo 2 0 2 Flashes
T2 (evaporator) < -3°C SerrNo 8 0 3 Flashes
Comp/refrig fault T3 > T4 + 15°C (in seq3) SerrNo 32 0 4 Flashes
Comp/refrig fault T0 - T1 < 8°C (in seq4) SerrNo 32 0 5 Flashes
Water circ fault T1 > S4 + 7°C SerrNo 64 0 6 Flashes
TRIAC/refrig fault T3 > 110°C SerrNo 128 0 7 Flashes
Thermistor T0 Fault Tflag 1 1 Flash* 1 Flash*
Thermistor T1 Fault Tflag 2 2 Flashes* 2 Flashes*
Thermistor T2 Fault Tflag 4 3 Flashes* 3 Flashes*
Thermistor T3 Fault Tflag 8 4 Flashes* 4 Flashes*
Thermistor T4 Fault Tflag 16 5 Flashes* 5 Flashes*
Notes:
* The green and red LED’s flash simultaneously in these cases.
(1) System may be in limp mode with call for heat satisfied (water in cylinder @ 70ºC
determined by mechanical thermostat).
(2) This condition creates a delay start for the compressor. This is not considered a fault.
(3) Ambient temperature too cold for heat pump operation. This is not considered a fault.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
14
Fault Finding
Fault Chart
Number Page
1 16
1.1 17
1.2 21
No Hot Water
7 43
Insufficient hot water 2 23
3 24
3.1 25
3.2 25
3.3 26
3.4 27
3.5 29
3.6 30
3.7 30
8.1 44
Software version
HPV 3.1, HPV 3.2
or no HPV
identification
8.3 44
4 32
4.1 33
4.2 33
4.3 34
4.4 35
4.5 36
4.6 37
4.7 38
4.8 39
4.9 – 4.13 40
4.14 40
8 44
System in boost or limp mode
Software version
HPV 4.0 or higher
8.2 44
Leaking water heater 5 41
Noisy water heater 6 42
Blowing fuse/circuit breaker 7 43

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
15
General Fault Finding Chart
Fault Diagnosis
No
hot water? YES 1
Insufficient
hot water?
NO
2
YES
System
in boost or limp
mode?
NO
3
YES
NO
5
YES
6
NO
Leaking
water heater?
Noisy
water heater?
7
YES
NO
Blowing fuse/circuit breaker
Boost or limp mode will be
indicated by any of the following
LED conditions:
Red solid or flashing.
Red & green flashing together.
No LEDs (Limp mode with
Robertshaw thermostat open)
4
HPV 3.1, HPV 3.2 or
no HPV identification
HPV 4.0 or higher
What is the
controller
software
version?
Note: For more information on LED indication refer to pages 12 and 13.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
16
Fault Finding Chart 1
1
Warning: Terminals may be ‘live’.
Wear Personal Protective
Equipment to prevent risk of
electric shock.
Is 240
volts present at
the terminal
block? Test 1
1.1
YES
Is
the heater
connected to an
off peak
tariff?
NO
Off peak connection is unsuitable for Heat
Pump models. Connect to continuous tariff or
‘off peak 2’ if available
YES
Is the
isolating switch
or time clock
turned off?
NO
Restore power and advise customerYES
Is the
fuse blown at the
switchboard?
NO
Fault in household electrical wiringNO
Reset circuit breaker
or rewire fuse
YES
Did
the fuse or
circuit breaker blow
again?
7
YES
1. Heat pump connected to mixed circuit,
possible excessive current draw or another
appliance with a fault
2. Faulty circuit breaker or fatigued fuse wire
3. Unit may be short cycling due to faulty
thermostat
NO
No Hot Water

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
17
Fault Finding Chart 1.1
Note: Ensure you
wait the full five
minutes before
progressing from
this point.
1.1
Are the
thermostat contacts
closed? NO Replace thermostat.
Test 2
No Hot Water
Is there
240V at the
control board &
relay?
Test 3 Wiring incorrect.
Check control board wiring loom
plug (lower thermostat to control
board wiring loom).
NO
Test 4
What is the
status of the
control boards
LED’s five
minutes after
resetting?
Replace control board.
Red solid or Red and
Green LED’s indicating
simultaneously
Green flashing
Green solid
No indication
1.2
Replace sensor strip.
Replace control board (system
should have been operating in
boost mode after five minutes
from resetting) then check
system operation as a second
fault may be present.
YES
Note: To reset heat
pump switch power off,
wait for 30 seconds
then switch back on.
Reset heat pump &
wait five minutes
before progressing
from this point.
Is the
compressor
running?
Is the
sensor strip
working? NO
YES
Is the
refrigeration
system
heating?
YES
NO
YES
NO
To check if the refrigeration system is
heating feel the braided flexible hose
from the heat exchanger water outlet.
What is the
controller
software
version? HPV 3.1, HPV 3.2 or
no HPV identification
HPV 4.0 or higher
Is
sensor T3
working?
YES
Replace sensor T3.NO
Test 5
System working ok. The element circuit should be
checked as a temporary condition may have caused the
appliance to enter boost mode. If in boost mode and the
element circuit is not operational the cylinder water will
be cold and the system cannot reset itself automatically.
Replace control board.
YES
Is the
evaporator fan
operating?
YES
3.6
NO
1.2
Red flashing
Is
the air flow
obstructed?
NO
Remove obstruction or clean
evaporator.
YES
Note: For more information on LED indication refer to pages 12 and13.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
18
Component Tests 1, 2, 3 & 6
Tests 1 Test 2
240
Warning – ‘Live’ equipment wear
Personal Protective Equipment
when conducting this test.
Using a multimeter on the AC voltage
scale, measure between the terminals of
the terminal block located behind the
element access cover. The following
measurements should be obtained:
Active & Neutral – 240 volts.
Active & Earth – 240 volts.
Neutral & Earth – 0 volts.
Warning - Ensure power is
isolated before conducting this
test.
Using a multimeter on the ohms scale,
measure between the terminals of the
mechanical thermostat. The following
results should be obtained:
1L & 2T – 0 ohms.
3L & 4L – 0 ohms.
Test 3 Test 6
240
240
Warning – ‘Live’ equipment wear
Personal Protective Equipment
when conducting this test.
Using a multimeter on the AC voltage
scale, measure between the top 2 terminals
of the heat pump module terminal block.
Normal voltage is 240 volts.
Warning – ‘Live’ equipment wear
Personal Protective Equipment
when conducting this test.
Using a multimeter on the AC voltage
scale, measure between the A return and
Neutral terminals of the terminal block
located behind the element access cover.
Normal voltage is 240 volts.
Note: Refer to page 19 for component test 4 and page 20 for component test 5.

TM025 Rheem Heat Pump Service Instructions REV: B
Date of Issue: 02/08/07
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
19
8.49
Component Test 4
Warning – ‘Live’ equipment wear Personal Protective Equipment when
conducting this test.
Sensor Strip Testing: Unplug the sensor strip plug from the control board and using a
multimeter on the kilo-ohms scale, measure between the pins of the sensor strip plug*.
There are six individual tests to be performed as there are six individual sensors contained
along the length of the sensor strip (sensors S0 – S5). As the resistance of each sensor
will change according to its temperature, the resistance measurements for each sensor will
need to be checked against the Temperature/Resistance Table shown below. For this
reason it is best to empty the tank of hot water and then measure the cold water
temperature at the T&PR so a known temperature datum can then be applied to all
sensors which should then in turn all have similar resistance value when tested.
Sensor Test Points
S0 – Between Pins 1 and 9
S1 – Between Pins 2 and 9
S2 – Between Pins 4 and 9
S3 – Between Pins 6 and 9
S4 – Between Pins 3 and 8
S5 – Between Pins 3 and 10
*Note: The sensor strip plug socket test points are quite small, Fine Probe Adapters (part
number WH0020082) can be utilised as probe extensions. Alternatively small pins may be
used however ensure good contact is made when testing.
Sensor Strip Temperature / Resistance Table
T (°C) R (kΩ) T (°C) R (kΩ) T (°C) R (kΩ) T (°C) R (kΩ) T (°C) R (kΩ)
-10 37.45 10 15.45 30 7.037 50 3.485 70 1.853
-9 35.73 11 14.82 31 6.782 51 3.371 71 1.799
-8 34.11 12 14.22 32 6.537 52 3.262 72 1.743
-7 32.56 13 13.65 33 6.302 53 3.157 73 1.695
-6 31.10 14 13.10 34 6.076 54 3.055 74 1.646
-5 29.71 15 12.58 35 5.86 55 2.957 75 1.589
-4 28.39 16 12.09 36 5.653 56 2.863 76 1.552
-3 27.13 17 11.61 37 5.454 57 2.773 77 1.508
-2 25.94 18 11.16 38 5.264 58 2.686 78 1.465
-1 24.81 19 10.72 39 5.081 59 2.602 79 1.424
0 23.73 20 10.31 40 4.905 60 2.521 80 1.384
1 22.71 21 9.913 41 4.736 61 2.442 81 1.345
2 21.73 22 9.535 42 4.574 62 2.367 82 1.307
3 20.81 23 9.173 43 4.418 63 2.295 83 1.271
4 19.92 24 8.826 44 4.269 64 2.225 84 1.236
5 19.09 25 8.495 45 4.125 65 2.157 85 1.202
6 18.29 26 8.177 46 3.987 66 2.092 86 1.169
7 17.52 27 7.873 47 3.854 67 2.029 87 1.137
8 16.80 28 7.583 48 3.726 68 1.968 88 1.107
9 16.11 29 7.304 49 3.603 69 1.91 89 1.077
Sensor strip plug
pin configuration
Testing the
sensor strip