Rheem W2W Series Technical Document

This water heater must be installed and serviced by an qualified person.
Please leave this guide with a responsible officer.
Owners Guide
and
Installation Instructions
Commercial Water to Water
Heat Pump Water Heater
WMKA21549

PATENTS
This water heater may be protected by one or more patents or registered designs.
® Registered trademark of Rheem Australia Pty Ltd.
™ Trademark of Rheem Australia Pty Ltd.
Notice to Victorian Customers from the
Victorian Plumbing Industry Commission.
This water heater must be installed by a licensed person as required by
the Victorian Building Act 1993.
Only a licensed person will give you a Compliance Certificate, showing that
the work complies with all the relevant standards. Only a licensed person will
have insurance protecting their workmanship for 6 years. Make sure you use
a licensed person to install this water heater and ask for your Compliance
Certificate.

3
CONTENTS
RESPONSIBLE OFFICER –We recommend you read pages 4 to 18.
The other pages are intended for the installer but may be of interest.
Contents.......................................................................................3
About Your Water Heater............................................................4
How Your Water Heater Works...................................................8
Regular Care ..............................................................................12
Water Supplies...........................................................................14
Save A Service Call ...................................................................16
Installation..................................................................................19
Heat Pump And Tank Assembly ..............................................31
Manifold Installations................................................................35
Connections –Plumbing ..........................................................38
Commissioning..........................................................................56
Draining The Water Heater .......................................................68
TROUBLE SHOOTING...............................................................68
Rheem Heat Pump Water Heater Warranty - Australia & New
Zealand Only -............................................................................70

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ABOUT YOUR WATER HEATER
WATER HEATER APPLICATION
This water heater is designed for the purpose of heating potable water by
simultaneously reducing building chilling load. Its use in an application other than
this may shorten its life.
MODEL TYPE
Congratulations for choosing a Rheem®
commercial water to water (W2W) heat
pump water heater. The Rheem W2W
heat pump water heater is designed for
outdoor or indoor installation.
HOW HOT SHOULD THE WATER BE?
The heat pump (compressor, evaporator
and condenser) will operate until a water
temperature of up to 65C is reached.
To meet the requirements of the National
Plumbing Standard (AS/NZS3500.4) the
temperature of the stored water must not
be below 60C.
HOTTER WATER INCREASES THE
RISK OF SCALD INJURY
This water heater can deliver water at
temperatures which can cause scalding.
Check the water temperature before use,
such as when entering a shower or filling
a bath or basin, to ensure it is suitable for the application and will not cause scald
injury.
We recommend and it may also be required by regulations that an approved
temperature limiting device be fitted into the hot water pipe work to the bathroom
and ensuite when this water heater is installed. This will keep the water
temperature below 50C (55C in NZ) at the bathroom and ensuite. The risk of
scald injury will be reduced and still allow hotter water to the kitchen and laundry.
TEMPERATURE ADJUSTMENT
Set Point Quick Setting
Press ‘prg’ from the main display screen and the Set Point page will appear.
Cursor will be on the set temperature. Pressing the up and down keys will
adjust the setting in 0.1 increments. Hold down for rapid change. Press ’Enter’
to confirm change. Press ‘esc’ to return to the main display screen. Refer to
page 51 for more information.
minimum recommended
stored water temperature
maximum recommended
supply temperature to
bathrooms and ensuites

ABOUT YOUR WATER HEATER
5
WARNING
This water heater is only intended to be operated by persons who have the
experience or the knowledge and the capabilities to do so. This water heater is
not intended to be operated by persons with reduced physical, sensory or mental
capabilities i.e. the infirm, or by children. Children should be supervised to ensure
they do not interfere with the water heater.
This water heater uses 415V / 240 V AC electrical power for operation of the
control systems and other electrically operated components. The removal of the
access cover(s) will expose 415V / 240 V wiring. They must only be removed by
a qualified person.
SAFETY
This water heater is supplied with built in Rheem IQ Controller which controls low
and high pressure switches, low temperature cut off, temperature safety switch
and flow switch.
Additionally, the compressor is fitted with thermal overload protection, the
condenser heat exchanger is fitted with a pressure relief valve and the storage
tanks are supplied with a combination temperature pressure relief valve. These
devices must not be tampered with or removed. The water heater must not be
operated unless each of these devices is fitted and is in working order.
If the electrical supply conduit to the water heater is damaged, it must be
replaced by a qualified person in order to avoid a hazard. Phone your nearest
Rheem Service Department or Accredited Service Agent (or Service Centre in
NZ) to arrange for an inspection.
Warning: For continued safety of this water heater it must be installed,
operated and maintained in accordance with the Owner’s Guide and Installation
Instructions.
The Rheem warranty may not cover faults if relief valves or other safety
devices are tampered with or if the installation is not in accordance with
these instructions.

ABOUT YOUR WATER HEATER
6
TO TURN OFF THE WATER HEATER
Switch off the electrical supply at the isolating switch to the water heater
Close the cold side and hot side water isolation valve at the inlets to the water
heater.
TO TURN ON THE WATER HEATER
First, ensure the water is connected to storage tanks, the system is filled with
water and all valves between the tanks and the water heater are open
Open the cold side and hot side water isolation valve fully at the inlets to the
water heater.
Switch on the electrical supply at the isolating switch to the water heater.
Note: The water heater may not turn on immediately when it is first switched on,
if it is switched on within 20 minutes to 2 hours of it having been switched off at
the isolating switch, or the heat pump has just completed a heating cycle. The
water heater will wait until the conditions for start-up are favourable in order to
protect the compressor from damage. This may take up to 20 minutes to 2 hours.
The auxiliary booster will operate instead of the heat pump if the heat pump is in
fault or sufficient energy is not available from the chiller.
HOW DO I KNOW IF THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on page 19. The water heater must be
installed:
by a qualified person, and
in accordance with the installation instructions, and
in compliance with Standards AS/NZS 3500.4, AS/NZS 3000 and all local
codes and regulatory authority requirements.
In New Zealand, the installation must also conform with Clause G12 of the New
Zealand Building Code.
DOES THE WATER CHEMISTRY AFFECT THE WATER HEATER?
This advice relates to the cold water side and hot water side of the heat
pump water heater.
The water heater is suitable for most public water supplies, however some
water chemistries may have detrimental effects on the water heater, its
components and fittings. Refer to “Water Supplies” on page 14. If you are
not sure, have your water chemistry checked against the conditions described
on pages 14 to 15.

ABOUT YOUR WATER HEATER
7
HOW LONG WILL THE WATER HEATER LAST?
Your water heater is supported by a manufacturer’s warranty (refer to page 72).
There are a number of factors that will affect the length of service the water
heater will provide. These include but are not limited to the water chemistry, the
water pressure, temperature (inlets and outlets) and the water usage pattern.
Precautions
Where damage to property can occur in the event of the water heater leaking,
the water heater must be installed in a safe tray or be suitably bunded.
Construction, installation and draining of a safe tray must comply with AS/NZS
3500.4 and all local codes and regulatory authority requirements.
The water heater must be maintained in accordance with the Owner’s Guide and
Installation Instructions. Refer to “Regular Care” on page 12.
If this water heater is to be used where an uninterrupted hot water supply is
necessary for your application, or business you should ensure that you have
back up redundancy within the hot water system design. This should ensure the
continuity of hot water supply in the event that this water heater were to become
inoperable for any reason. We recommend you seek advice from your plumber
or specifier about your needs and building back up redundancy into your hot
water supply system.
ENVIRONMENT
At the end of the service life of the heat pump water heater and prior to the water
heater being disposed of, a person qualified to work with refrigerants must
recover the refrigerant from within the sealed system. The refrigerant must not
be vented to atmosphere. Phone your nearest Rheem Service Department or
Accredited Service Agent (or Service Centre in NZ) to arrange for an inspection.

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HOW YOUR WATER HEATER WORKS
The Rheem commercial water to water heat pump is an instantaneous type and
does not have an integral storage cylinder. The unit is designed to be installed
indoors or outdoors. The water heater’s evaporator absorbs heat from the
returning chilled water circuit or condenser loop and transfers this heat into the
potable water. A circulator transfers
the heated water to a bank of storage
tanks. By taking heat from the chilled
water circuit, the heat pump reduces
load on chiller as colder water returns
to the building chiller circuit. The heat
pump produces a sound level of up to
59 dBA (measured at 3 metres) when
it is operating.
When hot water is drawn off and cold water enters the storage tanks, a remote
thermostat activates the compressor and circulating pumps of the water heater.
The chiller return water (building heat) is drawn in through the cold side inlet and
then through the evaporator (single wall heat exchanger), where heat is
transferred to a refrigerant fluid. The fluid is compressed and passes to the
condenser (double wall heat exchanger) where heat is transferred into the
potable water. The pump circulates water from the bottom of the storage tanks
through the heat exchanger and the heated water is circulated back into the
storage tanks. This process continues until the water in the storage tanks
reaches the set temperature.
The heat pump is designed to operate most efficiently at cold side temperatures
between a minimum of 12C and maximum of 35°C. Operation with higher cold
side inlet temperature is possible, however must be engineered in consultation
with Rheem. The efficiency of the water heater is relative to the building chilled
water circuit temperature and the incoming hot side (potable) water temperature.
Automatic safety controls are fitted to the water heater to provide safe and
efficient operation.
FREEZE PROTECTION
Ice may begin to form in the evaporator when the cold side outlet temperature
falls below 4°C or the flow rate of cold side water is excessively low or the pump
on the cold side fails, and this may damage the evaporator heat exchanger.

HOW YOUR WATER HEATER WORKS
9
To prevent this damage, the pumps for
both sides of the water heater are sized
and supplied by Rheem and the heat
pump is supplied with a flow switch
sensor and a low temperature cut out
switch. The heat pump will terminate its
operation if poor flow rate is sensed or
the cold side outlet temperature or hot
side outlet temperature falls below
5°C.
AUXILIARY BOOST OPERATION
There are two types of auxiliary boost operation, which operate as follows:
ANTIFREEZE AUXILIARY BOOST OPERATION
When freeze protection activates, the heat pump will cease operating. It is then
possible to activate auxiliary heating mode.
In auxiliary heating mode the controller deactivates the heat pump and switches
to an auxiliary gas or electric water heater, if installed and activated in the menu.
A pump circulates water from the storage tanks through the auxiliary water heater
until the set temperature is reached.
When the cold side outlet temperature and hot side outlet temperature rises to
10°C, the auxiliary heating mode is deactivated and the heat pump starts
operating again.
For installations using multiple heat pumps in a master/slave configuration,
activation of antifreeze auxiliary boost operation on any heat pump activates the
auxiliary boost on all LAN connected heat pumps.
BACKUP AUXILIARY BOOST OPERATION
If the heat pump is in fault mode, the controller switches to an auxiliary gas or
electric water heater, if installed and activated in the menu. A pump circulates
water from the storage tanks through the auxiliary water heater until the set
temperature is reached.

HOW YOUR WATER HEATER WORKS
10
For multiple heat pump (Master/Slave) configuration, the auxiliary booster will
operate instead of the heat pumps if fifty percent (50%) or more heat pumps are
in fault.
For installations using multiple heat pumps in a master/slave configuration;
activation of backup auxiliary boost operation on any heat pump activates the
auxiliary boost on all LAN connected heat pumps.
The auxiliary boost should be set to 60°C.
The auxiliary boost will remain active until the water heater fault is cleared.
Warning: Rheem will not be responsible for higher utility bills due to
excessive use of auxiliary boost heater. It is the customers’ responsibly
to monitor the system regularly for its correct operation. Rheem
recommends monitoring via BMS (modules supplied separately).
MAINS PRESSURE
The water heater is designed to operate at mains pressure by connecting directly
to the mains water supply. If the mains supply pressure in your area exceeds
that shown on page 21, a pressure limiting valve must be fitted.
THERMAL CUT OUT
The refrigeration circuit is protected by thermal sensors. These will activate a
thermal cut out in the event of excessive heat in the refrigeration system.
If the thermal cut out has activated, the heat pump will not operate for a period
of 20 minutes to 2 hours. The water heater will make two more attempts to start
up. If the thermal cut out is tripped again after the third attempt, the system will
enter lock out and the alarm contacts will close. If connected to a BMS, this will
alert the user that the unit is not operating.
The lockout condition can be manually reset by switching the power to the water
heater off and then on.
CONTROL FUNCTIONALITY
A timer can be set through the heat pump control panel to limit the hours of
operation of the water heater (e.g. to reduce noise at night).
The operation of the heat pump can also be controlled by setting up tariff option
on the control panel to manage operating costs.