Solahart TM096A Operating instructions

This document is stored and maintained electronically by Rheem Technical Support. All printed copies are deemed “uncontrolled”
Rheem Australia Pty Ltd ABN 21 098 823 511
SERVICE INSTRUCTIONS
PowerStore Grid Interactive
Electric Water Heater
TM096A
Issued: Dec 2021
REV: AA
Issued: Aug 22
250E5X36
315E5X36

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
This document is stored and maintained electronically by Rheem Technical Support. All printed copies are deemed “uncontrolled”
2
CONTENTS
INTRODUCTION .................................................................................................................3
SAFETY WARNINGS..........................................................................................................3
GLOSSARY OF ACRONYMS .............................................................................................5
MODEL IDENTIFICATION...................................................................................................5
SPECIFICATIONS...............................................................................................................6
INSTALLATION...................................................................................................................6
PREVENTATIVE MAINTENANCE ......................................................................................7
COMPONENTS AND THEIR FUNCTION ...........................................................................9
System Components........................................................................................................9
Heater Components.........................................................................................................9
Heater Component Overview Diagram..........................................................................11
PRODUCT CHANGES ......................................................................................................12
EMI Filter Wiring Harness Discontinuation.....................................................................12
Software Changes .........................................................................................................12
WIRING DIAGRAMS .........................................................................................................13
Water Heater Wiring Diagram –All Models ...................................................................13
Water Heater Wiring Harness –All Models....................................................................14
PLUMBING DIAGRAM ......................................................................................................14
OPERATION......................................................................................................................15
Operating Instructions....................................................................................................15
Basic System Overview.................................................................................................16
Sequence of Operation..................................................................................................17
Operational Flow Charts................................................................................................23
MASTER CONTROLLER ..................................................................................................32
LED INDICATION..............................................................................................................33
FAULT FINDING................................................................................................................34
Common Complaints .....................................................................................................34
Confirming Powerstore Communications.......................................................................36
Fault Indication...............................................................................................................37
Fault Code Table ...........................................................................................................38
Fault Diagnosis Sequence –Fault Finding Charts.........................................................39
FAULT FINDING TESTS...................................................................................................61
COMMISSIONING PROCEDURE.....................................................................................65
COMPONENT ADJUSTMENT PROCEDURES ................................................................66
Adjusting the Temperature Limiting Valve .....................................................................66
Mechanical Thermostat Temperature Adjustment .........................................................67
Resetting Mechanical Thermostat ECOs.......................................................................67
COMPONENT REPLACEMENT PROCEDURES .............................................................69
DOCUMENT REVISION HISTORY...................................................................................80

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
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INTRODUCTION
The information provided in these instructions is based on the water heater being installed
and commissioned in accordance with the Installation Instructions provided with each water
heater.
Should you require further technical advice on a Solahart PowerStore Grid Interactive
Electric Water Heater contact Rheem Technical Support on 1300 712 863.
SAFETY WARNINGS
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 Solahart PowerStore Grid Interactive Water Heater in the minimum of time.
Safety precautions or areas where extra care should be observed when conducting tests
outlined in this service manual are indicated by print in bold italics and/or a warning symbol.
Take care to observe the recommended procedure.
Isolate power before conducting the indicated test.
Hot surface or liquid. Personal Protective Clothing (PPE) shall be worn to
reduce the risk of scalding.
General warning symbol. Observe the instructions accompanying the
symbol.
Live Testing
A number of test procedures detailed within this document require ‘live’
testing to be conducted.
All State and Territory Authorities stipulate requirements that must be met
before working live i.e. conducting a risk assessment and/or preparing a
safe work method statement and wearing appropriate PPE.
It is the responsibility of the service person to be aware of and comply
with the requirements of the State or Territory where the water heater is
installed before working ‘live’.
Under certain fault conditions it is possible for the metal jacket of a water
heater to become live. To check for a shock hazard in a suspect
installation, a Touch Voltage Test must be performed (refer page 4).
Heater Safety Warnings
This product contains electronic components that are sensitive to
electrostatic discharge (ESD). Appropriate precautions shall be taken to
prevent damage to electronic components.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
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Touch Voltage Testing
Under certain fault conditions it is
possible for the metal jacket of a
water heater to become live. The
electrical fault may be an internal
appliance issue or an issue with
the premises wiring.
In the example opposite, the
appliance metal jacket has
become live due to the appliance
active wire touching the metal
frame.
To check for a shock hazard in a suspect installation, a Touch Voltage Test must be
performed using the following equipment:
1. A high impedance multimeter with an input impedance greater than 5 Megaohm.
2. A 2 kΩ resistor box fitted with contact terminals (the 2 kΩresistor is used to simulate the
body resistance of a typical person).
3. A long trailing lead for connection to the premises earth electrode.
Procedure
Personal Protective Equipment (electrical insulating gloves) should be
worn when conducting this procedure toreduce the risk of electric shock.
1. Connect resistance box between metal casing of appliance and premises main earth
electrode (spike) using the long trailing lead (as depicted above).
2. Connect multimeter (set on AC voltage scale) to resistor box terminals and record
reading.
3. If reading is higher than 50 VAC (dry) or 25 VAC (wet), then there is a fault either with
the premises wiring or with the appliance.
4. To confirm earthing of the appliance:
•Electrically isolate appliance from electrical circuit.
•Conduct an earth continuity test to AS/NZS 3760 (pay particular attention to the
cordset earth on plug-in water heaters).
•If the earth continuity test is ok (≤0.5 ohms), the problem is with the premises wiring.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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GLOSSARY OF ACRONYMS
CFH –Call for heat.
CT –Current transformer.
ECM –External Control Mode.
EMU –Energy management unit.
ECV –Expansion control valve.
GIEWH –Grid interactive electric water heater.
HEMS –Home energy management system.
N/A –Not applicable. Depending on context may also mean not fitted or not relevant.
N/C –Normally closed i.e. normally closed contact.
N/O –Normally open i.e. normally open contact.
O/C –Open circuit.
PLT –Powerline telecommunication (communication via heater power supply wiring).
PLV –Pressure limiting valve.
PV –Photovoltaic.
PCB –Printed circuit board.
S/C –Short circuit.
T&PR –Temperature and pressure relief valve.
TLV –Temperature limiting valve.
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.
250
E
5
X
36
250 –250 Litres Storage Capacity
315 –315 Litres Storage Capacity
E –Electric
5 –Temperature Limiting Valve Fitted
X –10 Year Cylinder Warranty *
36 –3.6 kW
* When installed in a single-family domestic dwelling. Refer to Warranty section in Owners Guide and
Installation Instructions supplied with heater for terms and conditions.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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SPECIFICATIONS
General
Model
250E5
315E5
Rated Capacity
250 L
315 L
Maximum Water Supply Pressure (1)
With ECV
680 kPa
Without ECV
800 kPa
Water Connections
Cold Water Inlet
G¾B
G¾B
Hot Water Outlet
G¾B
G¾B
T&PR
RP½/15
Electrical
Power Supply
220 ~ 240 VAC 50 Hz Hard Wired
Nominal Power Max
3.6 kW
Nominal Current Max
15 A
Water Temperature Setting (2)
70°C ~ 83°C
Temperature Limiting Valve
Yes
Yes
Communication Protocols (using PLT)
TCP/IP
(1) Where the mains water supply pressure exceeds the values shown, an approved pressure limiting valve is
required.
(2) 70°C during normal operation via master controller. 80°C (± 3°C) via mechanical thermostats when operating
in independent legionella sterilisation mode or critical fault mode.
Water Heater Components
Model
250E5
315E5
Anode
1 x 1140 mm
1 x 1395 mm
Temperature Limiting Valve Outlet Temperature
50⁰C
T&PR Valve
1000 kPa
Master Controller
Solahart
Top Heating Unit (3)
Element 1 Rating
3600 W
Bottom Heating Unit (3)
Element 1 Rating
500 W
Element 2 Rating
1000 W
Element 3 Rating
2000 W
Temperature Sensor Strip (Temp Sensors TH1 ~ TH5)
Refer to table on page 62
Legionella Temperature Sensor TH7 (4)
Refer to table on page 61
Bottom Temperature Sensor TH9 (4)
Top Mechanical
Thermostat
Make
Robertshaw ST1205134D80 (select)
Nominal Setting
Opens 80°C ± 3°C. Closes @ 72⁰C ± 2°C
ECO
Trips @ 87 ~ 93°C. Manual reset @ 82°C
Bottom Mechanical
Thermostat
Make
Robertshaw ST1205134D80 (select)
Nominal Setting
Opens 80°C ± 3°C. Closes @ 72⁰C ± 2°C
ECO
Trips @ 87 ~ 93°C. Manual reset @ 82°C
(3) Only one heating unit can operate at a time (maximum 3600 W).
(4) Single unit dual sensor comprised of bottom temperature sensor TH9 and legionella temperature sensor
TH7.
INSTALLATION
Solahart PowerStore Grid Interactive Electric Water Heaters are suitable for indoor or
outdoor installation and must be installed in accordance with AS/NZS 3000,
AS/NZS 3500.4, all local codes and regulatory authority requirements and the Installation
Instructions supplied with the water heater and any ancillary components.
Note: If the water heater is installed without an EMU, or power meter, or connection to a
home energy management system (HEMS), then it will operate as a conventional twin
element electric water heater only, with a setpoint of 70⁰C with element switching performed
by the heater’s master controller according to TH1 sensor for top element heating, and TH9
for bottom element heating.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
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PREVENTATIVE MAINTENANCE
Servicing must be performed by a suitably qualified person.
Annual Service
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 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.
2. Check for discharge from the ECV if fitted. When the element 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.
3. Check for leaks at all tank fittings.
4. Check for signs of excessive corrosion on the water heater jacket.
5. Visually check the unit for any potential problems.
6. If a safe tray is installed, check to ensure the drain pipe is not blocked.
7. Ensure master controller fins have adequate airflow and are free of insects/debris.
8. Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
9. Remove TLV and clean or replace TLV cold water inlet strainer, non-return valve and
hot water inlet strainer, then reinstall TLV. Refer to component replacement procedure
15 on page 76.
10. Check and adjust TLV if required. Refer to ‘Adjusting the Temperature Limiting Valve’
on page 66.
11. Contact CET Support by texting your mobile number to 0488 824 202 requesting a call
back to assist in confirming that there are no faults present and that the water heater is
functioning correctly.
Major Five Year Service
It is recommended that a major five year service be conducted on the water heater.
Note: The five year service androutine replacement of any components, such as the anode,
relief valve(s) and TLV, are not included in the Solahart warranty. A charge is to be made
for this work. Only genuine replacement parts should be used on the water heater.
1. Replace the T&PR valve. Refer to component replacement procedure 13 on page 75.
2. Replace the TLV. Refer to component replacement procedure 15 on page 76.
3. Inspect and flush the expansion control valve (if fitted). If required, replace the valve.
4. Inspect and if required, replace the anode.
5. For water supplies which are either softened or desalinated, or where the water supply
may alternate between a water tank and a reticulated public supply or another supply,
or where there is a variable supply (e.g. from a bore or public reticulated supply from
various water sources), the anode must be inspected (and replaced if there is any sign
of depletion) within five years of installation, and within every five years thereafter.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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For all water supplies, if the anode is not replaced during a major service then in any
event, the anode must be replaced at ten years. Refer to the 'Anode Inspection and
Replacement' section in the Owner’s Guide and Installation Instructions for full details.
6. Check electric heating units for excessive calcium build up or corrosion and replace if
necessary.
7. Check for leaks at all tank fittings.
8. Check for signs of excessive corrosion on the water heater jacket.
9. Visually check the unit for any potential problems.
10. If a safe tray is installed, check to ensure the drain pipe is not blocked.
11. Ensure master controller fins have adequate airflow and are free of insects/debris.
12. Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
13. Restore power.
14. Contact CET Support by texting your mobile number to 0488 824 202 requesting a call
back to assist in confirming that there are no faults present and that the water heater is
functioning correctly.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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COMPONENTS AND THEIR FUNCTION
System Components
Grid Interactive Electric Water Heater (GIEWH): The PowerStore GIEWH provides a
means of storing energy by heating water utilising special grid tariffs and/or excess power
from a PV system (if a PV system is installed). The GIEWH reports the heater’s tank charge
and status to the EMU via PLT communication, and the EMU reports to the web monitoring
service via ethernet connection to the premises modem. Note: If the GIEWH is installed
without an EMU, or power meter, or connection to a home energy management system
(HEMS), then it will operate as a conventional twin element electric water heater only.
Energy Management Unit (EMU): A third-party electronic device utilised to communicate
site specific and system status information with a third-party web monitoring service (such
as CET onWatch portal). The EMU can also monitor the flow of power to and from the
premises using a power meter and send heating requests to the heater to self-consume
solar energy generated if a PV system is installed or if special grid tariffs are available.
Power Meter: A third-party electronic device utilised to monitor the flow of power to and
from the premises (from premises only if a PV system is installed).
Home Energy Management System (HEMS): A combination of hardware and software
that allows the user to automatically monitor and control energy production and usage in a
premises. For GIEWHs, this is typically the EMU & power meter.
Heater Components
Master Controller: An electronic device utilised to control water heater operation during
normal operation. Refer to 'Master Controller' on page 32 for more information.
Current Transformer (CT): An electrical device inside the master controller utilised for
water heater power consumption measurements.
Heating Units: A tubular device containing electric resistance elements that convert
electrical energy to heat. Each GIEWH has two heating units; one heating unit is located in
the top section of the tank and the other near the bottom of the tank. Only one heating unit
can be energised at a time.
The top heating unit has a single 3600 W element. The bottom heating unit has three
elements; 500 W, 1000 W and 2000 W.
Temperature Sensors: Thermistor type sensors are utilised to sense the water temperature
at various locations against the storage tank face and are monitored by the master controller.
The resistance value of each sensor will change according to the detected temperature, and
the master controller utilises the resistance value, which has a corresponding temperature
value, to determine mode of operation. There are seven temperature sensors that are
located at the following positions on the storage tank:
•Bottom/legionella temperature sensor. This is a single unit dual sensor comprised of
bottom temperature sensor TH9 and legionella temperature sensor TH7. The sensor is
fitted to a clip attached to the bottom mechanical thermostat and connects to the master
controller via a plug-in ribbon cable. Bottom temperature sensor TH9 is utilised for bottom
heating unit monitoring/control and controller legionella sterilisation monitoring/control.
Legionella temperature sensor TH7 is utilised for independent (backup) legionella
sterilisation monitoring/control.

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•Temperature sensor strip comprised of five sensors (temperature sensors TH1 ~ TH5)
and a 10 Kilo ohm resistor. Utilised for tank heat monitoring and heating calculations and
located in a vertical aluminium duct in contact with the cylinder wall. The temperature
sensor strip connects to the master controller via a plug-in ribbon cable.
Mechanical Thermostats: During normal operation, the water
temperature is maintained by the master controller which utilises
temperature sensors to determine the water temperature at
various locations in the storage tank.
Top and bottom mechanical thermostats are also fitted to the
water heater and are utilised to control the water temperature if
the master controller enters independent legionella sterilisation
mode or critical fault mode. Each thermostat's controlling
contacts are set at 80°C and MUST NOT be altered (yellow dial).
Each mechanical thermostat has an integral double pole manual reset over temperature cut-
out (ECO) to provide additional over temperature protection in case the mechanical
thermostat controlling contacts fail.
The ECO contacts open at 87 ~ 93ºC. The ECO will not reset automatically and must be
manually reset by pressing and releasing the ECO reset button after temperatures have
fallen to a safe level (≤ 82°C). DETERMINE CAUSE OF OPERATION.
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.
Expansion Control Valve (ECV): A valve designed to provide automatic relief by
discharging water in case of excessivepressure. Commonly utilisedin areas with poor water
quality in which case the pressure relief valve provides a safety back up.
The expansion control valve pressure rating must not exceed 80% of the
T&PR valve rating
Temperature Limiting Valve (TLV): A valve that controls its outlet temperature to a preset
value. The TLV mixes cold water with hot water from the cylinder hot water outlet to provide
a hot water outlet temperature not exceeding 50⁰C.
Pressure Limiting Valve (PLV): 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.
Inlet 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 throughout 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.
Rating Label: The rating label details the model number, serial number and other
specifications and is located on the left hand side of the water heater above the T&PR valve.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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Heater Component Overview Diagram
All Models
1
Master Controller
10
T&PR Valve
2
Bottom mechanical thermostat
11
Anode
3
Bottom Heating Unit *
12
EMI Filter Wiring Harness (discontinued)
4
Bottom/Legionella Temp Sensor (TH9 & TH7)
13
Temperature Limiting Valve **
5
Temperature Sensor Strip (TH1 ~ TH5)
14
Cold water Inlet Adapter
6
Top Mechanical Thermostat
15
Cold Water Flexible Pipe
7
Top Heating Unit (3600 W)
16
Quick Connect Fittings
8
Power Supply Terminal Block (A & N)
17
Plastic Insulated Covers
9
Power Supply Earth Connection
* Bottom heating unit has three elements (500 W, 1000 W and 2000 W)
** TLV has two integral strainers and a non-return valve

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PRODUCT CHANGES
EMI Filter Wiring Harness Discontinuation
An EMI filter wiring harness was fitted to models manufactured
prior to 01/10/2021 and is not available as a spare part. (Refer to
‘Water Heater Wiring Diagram – All Models’ on page 13 to
identify EMI filter wiring harness location if required).
If an EMI filter wiring harness is found to be faulty, it must be removed and discarded, and
a replacement master controller MUST be installed (replacement master controllers have a
built-in EMI filter and MUST NOT have the EMI filter harness fitted as well).
To remove and discard an EMI filter wiring harness and replace the master controller, refer
to component replacement procedure 4 on page 69.
Software Changes
Solahart may, at its discretion, provide remote patches or upgrades to the firmware or
software incorporated in the water heater, either directly or through a third-party service
provider. Currently, remote upgrades can only be performed via the third-party service
provider (such as CET), and are only possible if the water heater is connected to the internet
via an external control device such as an EMU.

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WIRING DIAGRAMS
Water Heater Wiring Diagram –All Models
DRED & RJ45 ethernet external interface connections are for future use and are not currently utilised.
Wiring diagram plug and corresponding
plug socket example
EMI Filter Wiring Harness *
If harness is present, it is connected between the
two plug and plug socket example shown opposite.
* Models manufactured prior to 01/10/2021 have an EMI filter wiring harness connected
between the master controller and bottom element four pin wiring plugs. Models
manufactured from this date do not have the EMI filter wiring harness (the EMI filter is built-
in to the master controller after this date). Refer to ‘Product Changes’ section on page 12
for more information.

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Water Heater Wiring Harness –All Models
The wiring harness connects between the top and bottom electrical access covers and is
also detailed in the wiring diagram on page 13.
PLUMBING DIAGRAM
PowerStore GIEWHs have an integral
TLV and deliver water not exceeding
50°C in accordance with AS 3498.
There is no need to install a separate
temperature limiting device to satisfy the
requirements of the Plumbing Code of
Australia (PCA) if a PowerStore GIEWH
is installed serving an application where
50°C is the maximum permissible hot
water temperature at the outlet of a
fixture or appliance used primarily for
personal hygiene, such as in a bathroom
or ensuite.
Circulated Hot Water Flow & Return System
PowerStore GIEWHs must not be installed as part of a circulated hot water flow and return
system in a building.

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OPERATION
Operating Instructions
The start up and shut down procedures assume that the water heater is full of water and
has been commissioned, and that all valves are positioned to allow water flow through the
heater.
To Turn the Water Heater ON
1. Turn ON circuit breaker/electrical isolator in switchboard marked 'Water Heater' or
‘HWS’.
2. Turn ON water heater electrical isolator located adjacent to the heater (if installed).
When power is provided to the water heater, it will automatically operate in initialisation
mode for 15 ~ 60 seconds after which time it will operate according to the master controller
determined mode of operation.
To Turn the Water Heater OFF
1. Turn OFF water heater electrical isolator located adjacent to the heater (if installed).
2. Turn OFF circuit breaker/electrical isolator in switchboard marked 'Water Heater' or
‘HWS’.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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Basic System Overview
The PowerStore GIEWH operates as a staged power input water heater at times when there
are special grid tariffs or if there is excess PV power available (if a PV system is installed).
When special grid tariffs or excess PV power is available and water heating is required, the
water heater’s master controller and the EMU and/or power meter react enabling the water
heater to operate at or near an equivalent power consumption.
A combination of triple electric elements and electronic control enables a staged input from
500 W to full power (3500 W) in 500 W steps for the bottom heating unit, and 3600 W for
the single electric element top heating unit. This power control system allows the water
heater to operate whenever smaller or larger amounts of excess PV power is detected and
water heating is required.
An external control device (such as the Solahart CET Power Meter) monitors the flow of
power to and from the premises and communicates the amount of excess PV power
available to the EMU via PLT (powerline telecommunications). The EMU then passes the
required power reading to the GIEWH master controller via PLT. The GIEWH master
controller then adjusts the heating rate to consume the available excess power.
70 litres (250E models) or 90 litres (315E models) of 60⁰C hot water is maintained regardless
of excess PV power availability or special grid tariffs (ECM amenity maintenance mode).
Controller legionella protection is also ensured regardless of excess PV power availability
or special grid tariffs, and a separate independent electronic circuit, including independent
legionella temperature sensor TH7, provides a back up to ensure the entire tank volume is
heated to ≥ 60°C once every 7 days if such heating has not occurred during normal day to
day operation.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
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In the event of a component failure that causes the master controller to enter critical fault
mode, the water heater defaults to operating as a 3500 W bottom element water heater
controlled by a mechanical thermostat i.e. all three bottom heating unit elements are
energised.
For monitoring and fault indication purposes, the system can interface with a third-party web
monitoring portal (such as CET onSite) via the internet to provide feedback on the water
heaters performance.
Note: If the water heater is installed without an EMU, or power meter, or connection to a
home energy management system (HEMS), then it will operate as a conventional twin
element electric water heater only, with a setpoint of 70⁰C with element switching performed
by the heater’s master controller according to top temperature sensor TH1 for top element
heating, and bottom temperature sensor TH9 for bottom element heating. In this instance it
will not be able to be part of an intelligent water heating system or utilise special grid tariffs
and/or excess PV power.
Sequence of Operation
The GIEWH master controller has 11 modes of operation and starts from initialisation mode
when power is supplied/restored to the water heater, or if the master controller is reset via
a third-party web monitoring portal.
1. Initialisation Mode.
2. Bottom Thermostat Trip Calibration Mode.
3. Standalone Control Mode.
4. External Control Mode –Amenity Maintenance.
5. External Control Mode –Heat Request.
6. External Control Mode –No Heat Request.
7. Controller Legionella Sterilisation Mode.
8. Independent Legionella Sterilisation Mode.
9. Critical Fault Mode.
10. External Control Mode –AS4755 Request (currently disabled –for future use).
11. Factory Test Mode (currently only utilised during manufacturing end of line testing).
During any mode of operation, only one heating unit can be energised at any one time i.e.
top heating unit or bottom heating unit. Refer to 'Heating Unit Element Switching & Control'
on page 22 for element switching/control methodology.
Whilst operating in any normal mode of operation (modes 1 ~ 8), the master controller
continuously monitors the water heater and if a fault is detected the following occurs:
•If a warning fault is detected: A fault code is logged to memory and the heater operates
as normal in the current mode of operation, but possibly with impeded functionality
depending on the type of fault. The fault code can only be viewed via the third-party web
monitoring portal and no LED indication is provided.
•If a critical fault is detected: The master controller red LED illuminates on solid and
critical fault mode is entered to provide backup heating (refer to page 21 for operation
when in critical fault mode). The fault code can only be viewed via the third-party web
monitoring portal.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
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•If an independent legionella control fault is detected: A fault code (ELS_REPORTED)
is logged to memory and independent legionella sterilisation mode is entered to provide
sterilisation heating (refer to page 21 for operation when in independent legionella
sterilisation mode). The fault code can only be viewed via the third-party web monitoring
portal and no LED indication is provided.
•If a major fault is detected: A fault code is logged to memory and the heater operates
in the current mode of operation but heating is unlikely to occur. The fault code can only
be viewed via the third-party web monitoring portal and no LED indication is provided.
•Loss of Network Connection: If connection to EMU, power meter or ethernet is lost or
has not been configured, the master controller red LED provides one flash every 10
seconds and enters standalone control mode (refer to page 19 for operation when in
standalone control mode). Note: This is not a fault if an EMU or HEMS is not connected.
1. Initialisation Mode (Green & red LEDs fast flash)
Initialisation mode is entered when 240 VAC power is supplied to the water heater, or if
a master controller reset is performed via the third-party web monitoring portal (such as
CET onSite). Initialisation mode normally takes 15 ~ 60 seconds during which time the
following actions are performed:
1. Master controller green and red LEDs fast flash (0.25 seconds on, 0.25 seconds
off).
2. All master controller relays and triac output are de-energised (if energised).
3. Bottom/top changeover relay is energised for 5 seconds then de-energised.
4. Master controller performs a self-check routine.
If no faults are detected at step 4, the master controller determines the next mode of
operation according to parameter settings and external control inputs. Note: Bottom
thermostat trip calibration mode is immediately entered if first time operation.
2. Bottom Thermostat Trip Calibration Mode (No specific LED indication)
During first time operation, the master controller performs a heating cycle to determine
at what bottom temperature sensor TH9 value the bottom mechanical thermostat trips
(contacts open). The master controller utilises its internal current transformer (CT)
output to determine when the thermostat has operated i.e. loss of power to element
(thermostat trip) = 0 volt output from CT.
A bottom thermostat trip calibration may also be performed by resetting the master
controller to default factory settings via the third-party web monitoring portal (such as
CET onSite).
Bottom thermostat trip calibration normally takes 3 ~ 4 hours from a cold tank start
during which time the following actions are performed:
1. Top heating unit is energised (single element on) and operates until the top
mechanical thermostat opens (80⁰C ± 3⁰C) i.e. until CT provides 0 volt output.
2. Bottom heating unit is energised (all three elements on) and operates until the
bottom mechanical thermostat opens (80⁰C ±3⁰C) i.e. until CT provides 0 volt output.
Bottom temperature sensor TH9 value at this point is recorded as B_TRIP value.
The master controller then determines the next mode of operation according to
parameter settings and external control inputs.

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
This document is stored and maintained electronically by Rheem Technical Support. All printed copies are deemed “uncontrolled”
19
3. Standalone Control Mode (No specific LED indication)
Standalone control mode is entered directly from initialisation mode (or from bottom
thermostat trip calibration mode for first time operation) if an external control device has
not been connected/detected, or if the last communication with an external control
device has been > 15 minutes.
When in standalone control mode, the GIEWH functions similar to a standard twin
heating unit water heater but heating is controlled by the master controller (not the
mechanical thermostats) i.e., top heating unit is energised (single element on) until top
temperature sensor TH1 detects 70°C. Heating then switches to bottom heating unit (all
three elements on) and continues until bottom temperature sensor TH9 detects 70°C at
which time all heating ceases.
Bottom heating is maintained between 68°C and 70°C as detected by bottom
temperature sensor TH9 (i.e., 2⁰C differential), and if top temperature sensor TH1
detects ≤ 68°C (i.e., hot water usage), power is redirected to the top heating unit until
top temperature sensor TH1 detects 70°C.
4. External Control Mode –Amenity Maintenance (No specific LED indication)
ECM amenity maintenance mode is entered if an external control device has been
detected by the master controller and the amenity maintenance volume of hot water is
not available.
The amenity maintenance volume of hot water is 70 litres for 250E models and 90 litres
for 315E models at a temperature of ≥ 60⁰C and is calculated by the master controller
based on sensor strip temperature sensor TH1 ~ TH5 values. ECM amenity
maintenance mode ensures a usable amount of hot water is available during periods
when there are no special grid tariffs or little or no excess PV power is available.
When in ECM –amenity maintenance mode, the top heating unit is energised (single
element on) until top temperature sensor TH1 detects T_CUTOFF. If top mechanical
thermostat contacts open (contacts open at 80⁰C ± 3⁰C) before top temperature sensor
TH1 detects T_CUTOFF value, heating then switches to the bottom heating unit (all
three elements on) and continues until top temperature sensor TH1 detects B_TRIP
value at which time all heating ceases.
5. External Control Mode –Heat Request (No specific LED indication)
ECM heat request mode can only be entered if
•an external control device has been detected by the master controller, and
•special grid tariffs and/or excess PV power is available, and
•ECM amenity maintenance mode has been satisfied.
The master controller enters ECM heat request mode when it receives a heating request
from the EMU. The EMU selects which element configuration is appropriate for grid
management and the master controller energises the elements accordingly.
The element configuration can be any combination of bottom elements (500 W, 1000 W
and/or 2000 W) or top element (3600 W) or no elements (0 W). There are a total of 8
element configurations plus an additional 8 element configurations using the bottom
thermostat calibration trip point setting B_TRIP value determined when performing the
initial bottom thermostat trip calibration mode. The additional 8 combinations allow the
heater to store more energy at a setpoint just below the bottom mechanical thermostat
calibrated trip point B_TRIP value (approximately 80⁰C instead of 70⁰C).

TM096A PowerStore Grid Interactive Electric Water Heater Service Instructions
REV AA: Issued 22/08/2022
This document is stored and maintained electronically by Rheem Technical Support. All printed copies are deemed “uncontrolled”
20
•Bottom 500W: Provides 500W total.
•Bottom 1000W: Provides 1000W total.
•Bottom1000W + Bottom 500W: Provides 1500 W total.
•Bottom 2000W: Provides 2000W total.
•Bottom 2000W + Bottom 500W: Provides 2500 W total.
•Bottom 2000W + Bottom 1000W: Provides 3000 W total.
•Bottom 2000W + Bottom 1000W + Bottom 500 W: Provides 3500 W total.
•Top 3600W element: Provides 3600W total.
When in ECM heat request mode, the EMU provides the heat request and determines
setpoint, e.g. 70⁰C or B_TRIP value (approximately 80⁰C), however call for heat
operation is determined by the master controller utilising a 2⁰C differential.
6. External Control Mode –No Heat Request (No specific LED indication)
ECM no heat request mode can only be entered if
•an external control device has been detected by the master controller, and
•special grid tariffs and/or excess PV power is available, and
•ECM amenity maintenance mode has been satisfied.
ECM no heat request mode is entered if the master controller does not receive a heating
request from the EMU for 15 seconds and no other mode has priority. During normal
operation, the master controller remains in ECM no heat request mode indefinitely or
until the master controller determines that another mode of operation is required
according to parameter settings and external control inputs.
7. Controller Legionella Sterilisation Mode (No specific LED indication)
Controller legionella sterilisation mode is entered if bottom temperature sensor TH9
does not detect ≥ 62°C for a minimum of 33 minutes within a 6 day (144 hour) period.
If top temperature sensor TH1 detects < 62°C, the master controller energises the top
heating unit (single element on) until top temperature sensor TH1 detects ≥64°C (i.e.,
2⁰C differential). Heating then switches to the bottom heating unit (all three elements on)
and continues until bottom temperature sensor TH9 detects ≥64°C at which time all
heating ceases.
Bottom heating is maintained between 62°C and 64°C as detected by bottom
temperature sensor TH9, and if top temperature sensor TH1 detects < 62°C (i.e., hot
water usage), power is redirected to the top heating unit (single element on) until top
temperature sensor TH1 detects 64°C.
Heating continues in this manner until bottom temperature sensor TH9 detects ≥ 62°C
for 33 minutes in a single period. If bottom temperature TH9 detects < 62⁰C at any stage,
the 33 minute counter is reset to zero i.e. controller legionella sterilisation mode
continues for another 33 minutes.
At expiry of the 33 minute sterilisation period, the master controller determines the next
mode of operation according to parameter settings and external control inputs.