Rheem 325 II Series Operating instructions

First Issued April 2014
This document is stored and maintained electronically by Service. All printed copies are deemed uncontrolled.
Rheem Australia Pty Ltd ABN 21 098 823 511
Solahart
Everhot
RheemPlus
Rheem
325HAV
251325
554325
451325
251410
554410
551325
551410
SERVICE INSTRUCTIONS
325 & 410 Series II Heat Pump
TM077
Revision: 00
Issued: April 2014

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
CONTENTS
INTRODUCTION .................................................................................................................3
SAFETY WARNING.............................................................................................................3
POWER SUPPLY................................................................................................................3
ENVIRONMENTAL..............................................................................................................3
HEAT PUMP WATER HEATER MODEL IDENTIFICATION ...............................................4
HEAT PUMP WATER HEATER MODELS ..........................................................................5
SPECIFICATIONS...............................................................................................................6
PREVENTATIVE MAINTENANCE ......................................................................................8
REFRIGERATION TERMS AND THEIR MEANING............................................................9
COMPONENTS AND THEIR FUNCTION ...........................................................................9
CONTROLLER..................................................................................................................11
Power and Tank Sensor Connections ........................................................................11
Sensors ......................................................................................................................11
Reset Button...............................................................................................................12
OPERATION......................................................................................................................13
Refrigerant High Pressure Switch...............................................................................17
LED STATUS CODES.......................................................................................................18
OPERATIONAL SEQUENCES..........................................................................................20
System Start-Up and Standby Mode ..........................................................................20
Faults..........................................................................................................................21
Heat Pump Mode........................................................................................................22
Element Mode –Ambient ...........................................................................................23
Element Mode –Fault.................................................................................................24
Fault 9 –Heating Disabled .........................................................................................25
WIRING DIAGRAM............................................................................................................26
REFRIGERATION SYSTEM DIAGRAM............................................................................27
COMMON COMPLAINTS..................................................................................................27
SERVICE TECHNICIAN‟S HEAT PUMP KIT.....................................................................29
FAULT FINDING................................................................................................................31
Sensors ......................................................................................................................48
Refrigerant Charge.....................................................................................................54
Electrical Insulation Testing........................................................................................55
COMPONENT REPLACEMENT PROCEDURES .............................................................56
Storage Tank..............................................................................................................56
Heat Pump Module.....................................................................................................62
Refrigeration System..................................................................................................66
DOCUMENT REVISION HISTORY...................................................................................76

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
INTRODUCTION
The information provided in these instructions is based on the water heater being installed
in accordance with AS/NZS 3500.4, AS/NZS 3000 and the Owner‟s Guide and Installation
Instructions booklet provided with each water heater.
Should you require further technical advice on a 325 or 410 Series II Heat Pump Water
Heater, contact your nearest Rheem Service Department where all genuine replacement
parts are also available.
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 325 or 410 Series II Heat Pump Water Heater in the minimum amount 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.
General warning symbol. Observe the instructions accompanying the
symbol.
“Live” testing to be conducted. Personal Protective Clothing (PPE) shall
be worn to reduce the risk of electric shock. Refer to Rheem Safety
Procedure on electrical testing.
Isolate power before conducting the indicated test
Hot surface or liquid. Personal Protective Clothing (PPE) shall be worn to
reduce the risk of scalding.
WARNING: The heat pump must NEVER be operated with the refrigeration
system open to atmosphere.
POWER SUPPLY
325 & 410 Series II Heat Pumps will only operate on a sine wave at a
frequency of 50 Hz. Devices generating a square or saw tooth wave cannot
be used to supply power to the water heater.
ENVIRONMENTAL
R134a refrigerant is a controlled substance under the Ozone Protection
and Synthetic Greenhouse Gas Management Act. Only personnel qualified
and licensed to work with refrigerants may carry out service and repair
work on the sealed refrigeration system. During repair the refrigerant must
always be recovered, never vented to the atmosphere.
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.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
HEAT PUMP WATER HEATER MODEL IDENTIFICATION
All identification numbers are designed to convey detailed information about the water
heater to which it is attached. Model number, serial number and date of manufacture
should be quoted in all correspondence.
Rheem / Everhot Model Identification
5
5
1
325
07
2 –Everhot
4 –Rheem Optima
5 –Rheem
5 –Integrated
6 –Split
1 –Booster Element
4 –Booster Element and RheemPlus
Storage Capacity in Litres
04 –1800 watt element
05 –2400 watt element
07 –3600 watt element
Solahart Model Identification
325
H
A
V
36
Storage Capacity in Litres
H –Heat Pump
A –Air Sourced
V –Warranty Code *
24 –2400 watt element
36 –3600 watt element
* For details refer to the product‟s Owner‟s Guide.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
AquaMax Model Identification
Note: The 325 & 410 Series II Heat Pump module is not manufactured under the AquaMax brand,
however another brand module may be fitted to an existing AquaMax storage tank.
HP
325
-
36
-
1
B
HP –Heat Pump
Storage Capacity in Litres
36 –3600 watt element
1 –Number of Heat Pump Modules
B –Heat Pump Module B (AQ9290000)
HEAT PUMP WATER HEATER MODELS
The 325 & 410 Series II Heat Pump consists of a storage tank and a heat pump module,
which combine to make up the complete heat pump water heater.
The table below details the model numbers of the storage tanks and heat pump modules
that comprise each model of heat pump water heater.
“xx”indicates the booster element capacity:
04 or 18 = 1.8kW
05 or 24 = 2.4kW
07 or 36 = 3.6kW
Brand
Model
Storage Tank
Heat Pump
Module
Rheem
551325xx
=
T551325xx
+
182550
551410xx
T551410xx
Rheem Optima
451325xx
T451325xx
RheemPlus
554325xx
T554325xx
554410xx
T554410xx
Everhot
251325xx
=
T251325xx
+
182553
251410xx
T251410xx
Solahart
325HAVxx
=
T325HAVxx
+
182541

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
SPECIFICATIONS
Storage Tank
Parameter
Model
T5514101
T5544101, 3
T2514101
T451325
T551325
T5543253
T251325
T325HAV
HP325S36
Capacity (Litres)
410
325
325
325
Boost Capacity (Litres)
2002
1802
100 / 1802
206
Booster Element Rating (kW)
2.4 / 3.6
1.8 / 2.4 / 3.6
1.8 / 2.4 / 3.6
3.6
T&PR Valve Rating (kPa)
1000
1000
1000
1000
Maximum Inlet Water
Pressure (kPa)
With ECV
680
680
680
650
Without ECV
800
800
800
850
Water Connections
Inlet / Outlet
Rp ¾” (20mm)
Rp ¾” (20mm)
Rp ¾” (20mm)
Rp ¾” (20mm)
Heat Pump
Rp ½” (15mm)
Rp ½” (15mm)
Rp ½” (15mm)
Rp ½” (15mm)
T&PR
Rp ½” (15mm)
Rp ½” (15mm)
Rp ½” (15mm)
Rp ¾” (20mm)
Anode
Quantity
1
1
1
1
Length (mm)
1596
1340
1370
1480
Booster Element Thermostat Setting
(Fixed)
70ºC
70ºC
70ºC
70ºC
Booster Element ECO Setting
85ºC
85ºC
85ºC
84ºC
1410L model for use in QLD only.
2Boost volume with droopy element fitted –droopy element available in 2.4kW and 3.6kW only.
3RheemPlus models have the mains terminal block and earth connection on the opposite side of the tank to the heat pump module. RheemPlus
models therefore have three electrical covers on the storage tank.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Heat Pump Module
Parameter
Model
182550 / 182553 / 182541
Superheat Setting (Factory)
6K at 10ºC saturated suction temperature
Refrigerant Type
R134a
Refrigerant Charge
375 grams
Refrigerant High Pressure Switch
Cut Out:
Manual Reset Pressure:
2930kPa (± 103kPa)
2241kPa (± 207kPa)
Compressor Capacitor
25 µF +10/–5%, 370/440V AC, 50/60Hz
Compressor Current Draw
3.3A
Compressor Internal Overload Setting
(Automatic Reset)
Cut Out:
Cut In:
150°C
90°C
Compressor Winding Resistance
Run Winding –Red & Blue:
Start Winding –Red & Black:
4.18Ω at 20ºC
5.76Ω at 20ºC
Compressor Switching Relay
Type:
Coil Voltage:
Coil Resistance:
Omron
240V AC
30.51kΩ at 20ºC
Fan Capacitor
1.5µF ± 5%
Fan Winding Resistance
Run Winding –Blue & Black:
Start Winding –Blue & Brown:
650Ω at 20ºC
375Ω at 20ºC
Circulator Winding Resistance
on Speed Setting 1
602Ω at 20ºC
Circulator Capacitor
1.5µF +2/–5%
Circulator Speed Setting
1

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
PREVENTATIVE MAINTENANCE
It is suggested that the water heater be serviced annually, to retain optimum
performance.
Annual Service
Check for discharge from the T&PR valve. When the heat pump or element is
operating a small discharge of water may be evident. Operate the valve, easing the
lever to ensure the valve opens and reseats properly. Always open and close the
valve gently.
Check for leaks at all fittings.
Check for signs of excessive corrosion on the water heater and heat pump jackets.
Check for sludge build up and if necessary drain and flush tank.
Clear the circulator impellor & ensure free rotation.
Clean the condensate tray and check the condensate drain for blockages –clear if
necessary.
RheemPlus models: Service the tempering valve, refer to page 61.
Clean blockages and debris from evaporator fins, fan blades, grilles and louvers.
Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
Conduct an 'Electrical Insulation Test' on the water heater, refer to pages 40 and 55.
Check for vibration or excess noise from the compressor, fan and circulator.
Check the refrigerant charge by inspecting the sight glass.
Visually check the unit for any potential problems.
Confirm correct heat pump module operation.
Five Year Service
Replace the T&PR valve.
Inspect and flush the expansion control valve (if fitted). If required, replace the valve.
Inspect and if required, replace the anode.
If the anode is not replaced, it should be replaced within three years of this service.
Check the heating element for excessive calcium build up or corrosion and replace if
necessary.
Check for leaks at all fittings.
Check for signs of excessive corrosion on the water heater and heat pump jackets.
Check for sludge build up and if necessary drain and flush tank.
Clear the circulator impellor & ensure free rotation.
Clean the condensate tray and check the condensate drain for blockages –clear if
necessary.
RheemPlus models: Service the tempering valve, refer to page 61.
Clean blockages and debris from evaporator fins, fan blades, grilles and louvers.
Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
Conduct an 'Electrical Insulation Test' on the water heater, refer to pages 40 and 55.
Check for vibration or excess noise from the compressor, fan and circulator.
Check the refrigerant charge by inspecting the sight glass.
Visually check the unit for any potential problems.
Confirm correct heat pump module operation.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
REFRIGERATION TERMS AND THEIR MEANING
Condense –The action of a substance as it releases heat and changes state from a
vapour (gas) to a liquid.
Evaporate –The action of a substance as it absorbs heat and changes state from a liquid
to a vapour (gas).
Heat of Compression –The heat energy added to a substance by the act of compressing
it.
High Side –Components and pipework of a refrigeration system operating at high
pressure, generally the compressor case where a rotary compressor is utilised, discharge
line, condenser, liquid line, liquid receiver where utilised and filter drier.
Latent Heat –The „hidden‟ heat energy that causes a change in state of a substance,
without changing its temperature.
Low Side –Components and pipework of a refrigeration system operating at low
pressure, generally the evaporator, suction line and suction accumulator.
Saturated Liquid –A liquid at the point that it will boil with any increase in temperature, at
a given pressure.
Saturated Vapour –A vapour at the point that it will condense with any decrease in
temperature, at a given pressure.
Subcooled Liquid –A liquid at a temperature below its saturation point, at a given
pressure.
Superheated Vapour –A vapour (gas) at a temperature above its saturation point, at a
given pressure.
COMPONENTS AND THEIR FUNCTION
Anode (Sacrificial) –A metal alloy electrode installed in the water heater cylinder that
protects the cylinder from corrosion by galvanic action.
Compressor –An electromechanical device that increases the pressure of superheated
refrigerant vapour by decreasing its volume, as well as increasing its temperature due to
the addition of the heat of compression. The increase in pressure causes the refrigerant to
circulate through the refrigeration system.
Condenser –A heat exchanger containing three chambers; one for the refrigerant, one for
water and a third separating chamber which is open to atmosphere. The refrigerant enters
the condenser as a high pressure, high temperature superheated refrigerant vapour and
gives off its heat. This heat is absorbed by the water from the storage tank which is being
circulated through the water chamber in the condenser. As the refrigerant gives off its heat
and becomes cooler, it condenses (changes state) to a saturated liquid. Cooling of the
saturated liquid refrigerant continues such that it becomes subcooled.
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.
Discharge Check Valve –A valve in the refrigerant discharge line that allows refrigerant
to move in one direction only. The valve prevents refrigerant migrating back into the
compressor when the refrigeration system is not operating.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Evaporator –An aluminium finned copper coil where the low pressure, low temperature
refrigerant absorbs heat from the surrounding ambient air. As the refrigerant absorbs heat
and becomes warmer, it evaporates (changes state) to a saturated vapour. Heating of the
saturated refrigerant vapour continues such that it becomes superheated.
Filter Drier –A component fitted in the refrigerant liquid line. The filter drier traps
impurities and removes moisture from the sealed refrigeration system.
Fitting Liner –A plastic tube installed in the cold water inlet of the storage tank to provide
protection against corrosion through the life of the water heater.
Heating Element –A tubular device containing a resistive element, that converts electrical
energy to heat.
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.
Pressure Limiting Valve (PLV) –A valve that controls its outlet pressure to a
predetermined limit.
Process Tube –A short piece of copper pipework used for charging refrigerant into the
refrigeration system during manufacture.
Refrigerant High Pressure Switch –A pressure switch in the refrigerant discharge line
that opens when the refrigerant discharge pressure exceeds the switch rating.
Sensor –A device which changes resistance with a change in temperature, also known as
a thermistor. Sensors are used to measure temperature and feed the information back to a
control system.
Sight Glass –A component fitted in the refrigerant liquid line. The sight glass allows the
state (liquid/vapour) of the passing refrigerant to be observed, and includes a moisture
indicator.
Suction Accumulator –A device fitted in the refrigerant suction line, which accumulates
and prevents any liquid refrigerant from entering and damaging the compressor. Any liquid
refrigerant in the suction accumulator is evaporated or “boiled off” to a vapour.
Temperature and Pressure Relief (T&PR) 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.
Thermal Cut Out (ECO) –A manually reset temperature sensitive device mounted
against the water heater cylinder, which cuts off the supply of electrical energy.
Thermostat –A temperature sensitive device mounted against the water heater cylinder,
which controls the supply of electrical energy to maintain the stored water at the required
temperature.
Thermostatic Expansion (TX) Valve –A mechanical valve that expands the liquid
refrigerant to a lower pressure as it moves through the TX valve‟s orifice. The expansion
process also lowers the temperature of the refrigerant, to a point below that of the
surrounding ambient air. The TX valve has a bulb that senses the temperature of the
suction line at the evaporator outlet. The TX valve thermostatically meters the flow of
expanding refrigerant to the evaporator, in response to the temperature of the suction line
as measured by the bulb.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
CONTROLLER
Power and Tank Sensor Connections
Sensors
Four independent temperature sensors (thermistors) are utilised in the heat pump module.
The sensors are identified as follows:
Tank sensor
Evaporator sensor
Compressor sensor
Heat exchanger water outlet sensor
The sensors are monitored by the controller and provide information on specific
temperatures. This information is utilised to determine heater operation.
For more information on the sensors refer to the Sensor Testing section on page 48.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Reset Button
On the underside of the controller is a reset button.
The reset button may be used to cancel the start delay, or reset Fault 9. Fault 9 will not
disable all heating unless it has occurred 3 consecutive times however if Fault 9 has
occurred once, or twice consecutively, the reset button will reset the consecutive
occurrence count.
The reset button also clears any stored Fault Code from the controller memory.
The reset button does not function during System Start-Up or the Last Fault Code display
function, however may be used at all other stages of system operation.
To reset the system, press and hold the reset button until both LEDs come on
(approximately 2 seconds). After both LEDs come on, release the reset button. If the reset
button is held down for longer than 10 seconds, the reset will not occur.
When reset, the system returns to System Start-Up.
NOTES:
1. The refrigerant high pressure switch is manual reset and may also need to be reset
following the occurrence of Fault 9.
2. Resetting the compressor start delay prematurely after the compressor has been
operating may cause the compressor to trip out on its internal overload switch, if the
heat pump is operated. This is due to the compressor‟s inability to overcome the
residual pressure differential that will remain in the refrigeration system for a period
of time after the compressor has operated. The compressor‟s internal overload
switch will reset automatically, however the controller may detect Fault 9 prior to the
automatic reset occurring.
RESET BUTTON

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
OPERATION
The heat pump controller contains a main relay that ensures only the heat pump or the
booster element can be operated. The main relay will enable element operation in its un-
powered (off) state. Whenever power is available and element heating is not being used,
the controller energises the main relay to enable heat pump operation.
When heat pump operation is enabled and occurring, power for the compressor is passed
through an electronic switch called a triac, which is downstream of the main relay and
allows the controller to switch the compressor on and off in response to the demand for
heat pump heating.
Downstream of the triac, power for the compressor also passes through the load side of a
compressor switching relay. The compressor switching relay prevents compressor
operation in the event of high refrigerant pressure, via a high pressure switch in the
refrigeration system. The compressor switching relay will enable compressor operation in
its powered (on) state.
The compressor switching relay‟s coil side is fed power from the main relay when the main
relay is in its powered (on) state, via the refrigerant high pressure switch. This way, the
compressor switching relay is energised whenever heat pump heating enabled, and it will
not switch the compressor load unless it is de-energised as a result of the refrigerant high
pressure switch opening.
The 325 & 410 Series II Heat Pump Water Heaters utilise R134a refrigerant to transfer
heat from the atmosphere to the water in the storage tank.
The four main components of the sealed refrigeration system are the compressor,
condenser (heat exchanger), thermostatic expansion (TX) valve and the evaporator.
Refrigerant enters the compressor as a low pressure superheated vapour. The
compressor increases the pressure of the refrigerant vapour by decreasing its volume, as
well as increasing its temperature due to the addition of the heat of compression.
The high pressure, high temperature superheated refrigerant vapour flows to the
condenser (heat exchanger), where it gives off its heat. This heat is absorbed by the water
from the storage tank which is being circulated through a separate chamber in the
condenser. As the refrigerant gives off its heat and becomes cooler, it condenses
(changes state) to a saturated liquid. Cooling of the saturated liquid refrigerant continues
such that it becomes subcooled, meaning it is cooled to a temperature below its saturation
point.
The liquid refrigerant then moves through the thermostatic expansion (TX) valve, where it
is expanded to a lower pressure by moving through the TX valve‟s orifice. The expansion
process also lowers the temperature of the refrigerant, to a point below that of the
surrounding ambient air.
The TX valve has a bulb that senses the temperature of the suction line at the evaporator
outlet. The TX valve thermostatically meters the flow of expanding refrigerant in response
to the temperature of the suction line.
Following expansion, the low pressure, low temperature refrigerant moves into the
evaporator where it absorbs heat from the surrounding ambient air. As the refrigerant
absorbs heat and becomes warmer, it evaporates (changes state) to a saturated vapour.
Heating of the saturated refrigerant vapour continues such that it becomes superheated,
meaning it is heated to a temperature above its saturation point. This low pressure
superheated vapour then returns to the compressor to complete the cycle.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
SYSTEM START-UP
When power is first applied to the system, a 3 second System Start-Up process occurs.
During the 3 second System Start-Up, the green LED displays a rapid flash and the
element operates.
If a fault occurred during the last operation of the heat pump, a Fault Code will have been
stored. If a Fault Code is stored, that Fault Code will be displayed for 27 seconds after the
green LED‟s rapid flash, to indicate the last fault that occurred. See the LED Status Codes
section on page 18.
The element is energised if the red LED is displaying a stored Fault Code.
STANDBY MODE
Standby is an idle mode where power is available, but water heating is not required. The
green LED is illuminated and remains on.
The Freeze Protection function may be required whilst in Standby Mode, refer to the
Freeze Protection section on page 17.
HEAT PUMP MODE
Heat pump heating is initiated when the tank sensor detects a temperature less than 50°C.
Should the ambient temperature be outside the heat pump‟s operating limits or a fault is
detected, the system may switch to Element Mode at any stage during Heat Pump Heating
–see the Element Mode section on page 15.
Heat Pump Mode consists of three stages –System Check, Heat Pump Pre-Heating and
Heat Pump Heating.
System Check
During system check, the green LED will display one flash.
If the compressor sensor detects a temperature greater than 60°C, the system will
remain in Standby Mode until the compressor has cooled.
The controller checks that the 45 minute start delay has elapsed. The start delay may
have already elapsed, as it begins from the last compressor shut down. To begin the
start delay, the control system requires that power is available. The start delay does
not occur when power is applied to a new system for the first time.
Once the compressor has cooled and the start delay has elapsed, the system goes
to Heat Pump Pre-Heating.
The Freeze Protection function may be required whilst in System Check, refer to the
Freeze Protection section on page 17.
Heat Pump Pre-Heating
During Heat Pump Pre-Heating, the green LED will display 2 flashes.
The compressor and fan operate, and the circulator is initially off. The controller checks the
heat exchanger water outlet temperature every 30 seconds and when the heat exchanger
water outlet temperature is greater than 22°C, the circulator starts at its pre-set initial
speed.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
The circulator speed is then adjusted up or down to maintain the heat exchanger water
outlet temperature at a control point of 26°C. The circulator speed is adjusted every 30
seconds, in very small increments only. This ensures the controller is only able to maintain
the 26°C control point whilst the heat input from the refrigeration system is very low (as it is
at start-up).
As the refrigeration system begins to generate useful heat, the temperature at the heat
exchanger water outlet will rise more quickly and pull away from the control point. In this
way, the system will only proceed from Heat Pump Pre-Heating when the heat exchanger
water outlet temperature is rising at an acceptable rate.
The system goes to Heat Pump Heating under either of the following conditions:
Heat exchanger water outlet temperature is greater than 35°C for more than 2
minutes
The circulator speed reaches its maximum
Note: This means the system will always be in Heat Pump Pre-Heating for at least
2 minutes. This is because the circulator speed can not reach its maximum within 2
minutes, as it is only adjusted every 30 seconds.
Heat Pump Heating
During Heat Pump Heating, the green LED will display 3 flashes.
The compressor and fan continue to operate, and the circulator runs at full speed. The
system can not go from Heat Pump Heating back to Heat Pump Pre-Heating.
Heat Pump Heating ceases and the system returns to Standby Mode when the tank
sensor detects a temperature greater than 60°C.
ELEMENT MODE
At all times when power is available, the controller monitors the condition of the heat pump
system. Should the ambient temperature be outside the heat pump‟s operating limits or a
fault is detected, the controller initiates Element Mode which uses the booster element to
heat the water.
The booster element is controlled by the mechanical thermostat on the storage tank and
remains energised until the mechanical thermostat contacts open at approximately 70ºC,
at which point the element, controller and LEDS are de-energised.
Element Mode –Ambient
During Element Mode –Ambient, the green LED will display one long flash.
Element Mode –Ambient is utilised if the ambient temperature is outside the heat pump‟s
operating limits. The conditions for Element Mode –Ambient depend on whether or not the
heat pump is operating. Therefore, Element Mode –Ambient is utilised under the following
conditions:
The evaporator sensor temperature is less than 4°C or greater than 45°C when the
system is in Standby Mode and heating is required, and the compressor start delay
has elapsed (it has been 45 minutes since the compressor last ran)

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
The evaporator sensor temperature is less than –3°C or greater than 40°C when
the system is in Heat Pump Mode, any time after the first 10 minutes of compressor
operation
The Freeze Protection function may be required whilst in Element Mode –Ambient, refer
to the Freeze Protection section on page 17.
Element Mode –Fault
During Element Mode –Fault, the red LED will display a fault code indicating the fault that
has occurred –see the LED Status Code Tables on page 19.
The Freeze Protection function may be required whilst in Element Mode –Fault, refer to
the Freeze Protection section on page 17.
The faults listed in the table below will cause the water heater to enter Element Mode –
Fault.
Fault
Description
Condition
Fault 1
Compressor Over-Temperature Fault
The temperature detected by the compressor
sensor is greater than 110ºC.
Fault 3
Compressor Cooling Fault
During System Check, the compressor
sensor detects a temperature greater than
60ºC that persists for more than 90 minutes.
Fault 4
Tank Sensor Fault
The tank sensor has failed.
Fault 5
Evaporator Sensor Fault
The evaporator sensor has failed.
Fault 6
Compressor Sensor Fault
The compressor sensor has failed.
Fault 7
Heat Exchanger Water Outlet Sensor Fault
The heat exchanger water outlet sensor has
failed.
Fault 8
Water Flow Fault
The temperature detected by the heat
exchanger water outlet sensor is greater than
73ºC.
FAULT 9 –HEATING DISABLED
When Fault 9 is current and heating is disabled, the red LED will display 9 flashes.
Fault 9 is a Refrigeration System Fault and is detected when the compressor sensor
temperature is less than 12°C higher than the evaporator sensor temperature at any time
after the first 10 minutes of compressor operation.
First and Second Consecutive Occurrences of Fault 9
On the first and second consecutive occurrences of Fault 9, the heat pump will return to
System Check. Although the system attempts to re-start the first two consecutive times,
each occurrence of Fault 9 is still stored in the controller‟s memory as per the Last Fault
Code function –see page 18. After the first and second consecutive occurrences of Fault
9, the Fault 9 counter will be reset if a successful completion of a heat pump heating cycle
occurs.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Refrigerant High Pressure Switch
The refrigerant high pressure switch will stop the compressor if it trips. The refrigerant high
pressure switch is manual reset, therefore Fault 9 will occur when the compressor has
cooled after being stopped. Without intervention, the refrigerant high pressure switch will
remain open and therefore Fault 9 will re-occur after the system attempts to re-start.
Fault 9 Occurs 3 Consecutive Times
If Fault 9 occurs 3 consecutive times, the heat pump and element are disabled and no
further heating will occur. Cycling of the power supply will not reset this condition. For
instructions on how to reset Fault 9, refer to the Reset Button section on page 12.
The refrigerant high pressure switch is manual reset and may also need to be reset
following the occurrence of Fault 9.
The Freeze Protection function may be required whilst heating is disabled, refer to the
Freeze Protection section on page 17.
FREEZE PROTECTION
Whilst the Freeze Protection function is active, the green LED will display 4 flashes.
The Freeze Protection function is utilised in order to prevent the water within the heat
pump module freezing during low ambient conditions. (Only Series II heat pump models
are susceptible to freezing in the water circuit, due to the presence of a check valve in the
storage tank fittings).
If the compressor start delay has elapsed (it has been 45 minutes since the compressor
last ran) and the evaporator sensor temperature is less than 1°C for more than 15 minutes,
the circulator is switched on at full speed in order to circulate heated water from the
storage tank through the water circuit, to prevent freezing.
The circulator will switch off after 30 seconds.
The controller may utilise the Freeze Protection function when in any of the following
modes:
Standby Mode
System Check
Element Mode –Ambient
Element Mode –Fault
Fault 9 –Heating Disabled
Whilst the Freeze Protection function is active, the controller checks for Faults 1, 5 and 6
only.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Freeze Protection during Element Heating –Fault
Whilst the Freeze Protection function is active, the main relay is energised meaning it is
possible for the compressor to receive power if a controller hardware failure exists.
Therefore if Freeze Protection is required during Element Heating –Fault, it must still be
possible to monitor the condition of the compressor.
Therefore the Freeze Protection function is disabled under the following conditions:
If Fault 1 is current, as Fault 1 may indicate a compressor problem
If Fault 6 is current, as Fault 6 indicates the compressor temperature sensor has
failed and therefore the compressor condition can not be monitored
Whenever Fault 5 is current, the Freeze Protection function is also disabled as Fault 5
indicates the evaporator temperature sensor has failed and therefore it is not possible to
determine the need for Freeze Protection.
LED STATUS CODES
The 325 & 410 Series II Heat Pumps utilise a green and red LED to display information
about the operating status and/or fault conditions.
The green LED displays the operating mode; the red LED displays a fault condition. Refer
to the LED Status Code Tables on page 19 for the LED flash sequences and a description
of the condition.
In addition to displaying the current operating condition, the red LED is also able to display
the last fault condition that occurred, as this Fault Code is stored in the controller‟s
memory. If a current fault is being displayed, this is the same Fault Code that is stored in
the controller‟s memory.
To initiate the Last Fault Code function, turn the power off, wait 30 seconds then turn the
power back on again.
When power is restored to the system, the green LED will display a rapid flash during the 3
second System Start-Up process and the element operates.
If only the green LED illuminates after System Start-Up, a fault is not stored in the
memory.
If a fault has occurred in the past, the red LED will display the stored Fault Code for 27
seconds, then attempt normal operation. (For example, if the red LED displays 1 flash –
Fault 1 –the compressor discharge temperature has exceeded 110°C during the last heat
pump operation).
NOTE: Power must be available and the mechanical thermostat contacts must be closed
for this function to operate.
The element is energised whilst the red LED displays the stored Fault Code.
The stored Fault Code is automatically cleared from the controller memory each time the
heat pump completes a full cycle in Heat Pump Mode without detecting a fault, or when
the reset button is pressed.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
LED STATUS CODE TABLES
Operation
Green LED
Red LED
Condition
See the Operation section from page 13 for detailed information
Off
Off
No power or mechanical thermostat contacts open.
Rapid Flash
Off
System Start-Up.
Solid
Off
Standby Mode.
1 Flash
Off
Heat Pump Mode –System Check. The system waits for the compressor sensor temperature to fall to
at least 60°C and the start delay to elapse.
The start delay begins from the last compressor shut down, so may have already elapsed.
2 Flashes
Off
Heat Pump Mode –Heat Pump Pre-Heating. Compressor and fan on, circulator off for at least the first
30 seconds. Circulator starts when the heat exchanger water outlet temperature is greater than 22°C,
and runs at variable speed.
3 Flashes
Off
Heat Pump Mode –Heat Pump Heating. Compressor, fan and circulator on –circulator at full speed.
4 Flashes
Off
Freeze Protection. Circulator operates for 30 seconds, every 15 minutes.
Long Flash
Off
Element Heating –Ambient Mode.
Fault Codes
Fault
Green LED
Red LED
Condition
See the Operation section from page 13 for detailed information
FAULT 1
Off
1 Flash
Compressor Over-Temperature Fault, element heating enabled. Compressor temperature > 110°C.
FAULT 3
Off
3 Flashes
Compressor Cooling Fault, element heating enabled. Compressor temperature > 60°C.
FAULT 4
Off
4 Flashes
Tank Sensor Fault, element heating enabled.
FAULT 5
Off
5 Flashes
Evaporator Sensor Fault, element heating enabled.
FAULT 6
Off
6 Flashes
Compressor Sensor Fault, element heating enabled.
FAULT 7
Off
7 Flashes
Heat Exchanger Water Outlet Sensor Fault, element heating enabled.
FAULT 8
Off
8 Flashes
Water Flow Fault, element heating enabled.
FAULT 9
Off
9 Flashes
Refrigeration System Fault, heat pump and element heating disabled.
Solid
Solid
System reset –release button.
Notes
1. All faults will trigger Element Heating, except Fault 9 (9 red flashes).
2. Fault 9 will not disable all heating unless it has occurred 3 consecutive times. On the first and second consecutive occurrences of Fault 9, the heat pump will return to System Check.
3. To reset Fault 9 or cancel the start delay, press and hold the reset button until both LEDs come on.
4. The refrigerant high pressure switch is manual reset and may also need to be reset following the occurrence of Fault 9.

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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
OPERATIONAL SEQUENCES
System Start-Up and Standby Mode
Power to controller
Is there a stored Fault
Code?
Green LED –Off
Red LED –Display stored
Fault Code for 27 seconds
System Start-Up
for 3 seconds
Green LED –Rapid flash
A
Mechanical thermostat
contacts close
YES
FIRMWARE: V5.8
Main relay energised
B
Fault 9 has occurred
3 consecutive times? C
YES
Tank
sensor < 50ºC?
Evaporator sensor
< 4ºC or > 45ºC?
YES
YES
F
NO
Standby Mode
Green LED –On solid
NO At least 45 minutes
since the compressor
last ran?
Fault detected? D
NO
Green LED –Off
Red LED –9 flashes
NO
NO
At least 15 minutes
since the circulator
last ran?
YES
Evaporator sensor
< 1ºC for more than
15 minutes?
YES
Circulator on
Circ. Speed: Maximum
Green LED –4 flashes
YES
NONO
Faults 1, 5 or 6
detected?
Circulator has been
on for 30 seconds?
YES
Circulator off
Green LED –Off
D
Circulator off
Green LED –On solid
NO
NO
NO
E
Reset button pressed
during Standby Mode B
NOTES
1. The reset button will reset the
Fault 9 counter and clear any
stored Fault Code from the
controller memory.
2. The reset button does not
function during System Start-Up
or the Last Fault Code display
function.
YES
G
Green LED –OffYES