Rheem Gas Heavy Duty Water Heater Models 265 Litre and 275... Technical Document

This water heater must be installed and serviced by a qualified person.
Please leave this guide with the householder.
Owner’s Guide
and
Installation Instructions
Gas Heavy Duty
Water Heater
265 litre and 275 litre models

PATENTS
This water heater may be protected by one or more patents or registered designs
in the name of Rheem Australia Pty Ltd.
TRADEMARKS
®Registered trademark of Rheem Australia Pty Ltd.
TM Trademark of Rheem Australia Pty Ltd
Note: Every care has been taken to ensure accuracy in preparation of this publication.
No liability can be accepted for any consequences, which may arise as a result of its application.
Warning: Upon completion of the installation and commissioning of the water heater, leave this guide
with the householder or responsible officer. DO NOT leave this guide inside of the cover of the water
heater, as it may interfere with the safe operation of the water heater or ignite when the water heater is
turned on.

3
CONTENTS
RESPONSIBLE OFFICER –We recommend you read pages 4 to 16.
The other pages are intended for the installer but may be of interest.
About Your Water Heater............................................................................................................ 4
Regular Care ................................................................................................................................ 8
Water Supplies........................................................................................................................... 11
Save A Service Call ................................................................................................................... 14
Installation.................................................................................................................................. 17
Connections –Plumbing .......................................................................................................... 26
Connections –Electrical........................................................................................................... 29
Multiple Installations ................................................................................................................. 33
Commissioning.......................................................................................................................... 37
Lighting The Water Heater........................................................................................................ 38
Draining The Water Heater ....................................................................................................... 40
Temperature Control ................................................................................................................. 41
Warranty ..................................................................................................................................... 43

4
ABOUT YOUR WATER HEATER
WATER HEATER APPLICATION
This water heater is designed for the purpose of heating potable water. Its use in an application other than
this may shorten its life.
MODEL TYPE
The Rheem®Heavy Duty Gas water heater model you have chosen is
either a 265 litre or 275 litre indoor or outdoor quick recovery water
heater.
Water is stored in a vitreous enamel lined steel cylinder and heated by
a gas burner located under the cylinder. The heat produced by the
burner is transferred to the water through the base of the cylinder and
through the wall of a flue pipe which passes through the centre of the
cylinder. A flue baffle in this flue ensures the efficiency of the water
heater is correct. The gas supply to the burner is controlled by the
thermostat so the water is heated to a constant temperature.
Automatic safety controls are fitted to the water heater to provide safe
and efficient operation.
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 19, a pressure limiting valve must be
fitted. The supply pressure should be greater than 350 kPa for true mains pressure operation to be achieved.
HOW HOT SHOULD THE WATER BE?
The water heater has a maximum temperature setting of 82°C and a
minimum temperature setting of 60°C. Refer to “Temperature
Adjustment” on page 5.
For applications requiring sanitising temperatures, the thermostat
should be set at 82°C. Note: For temperatures above 80°C, a
circulator must be installed.
To meet the requirements of the National Plumbing Standard the
temperature of the stored water must not be below 60°C.
If this water heater is installed as an in-series booster water heater as
part of a commercial solar water heating system, to maximise solar
contribution it is recommended the thermostat is set at 60°C, unless
sanitising temperatures are required.
Note: AS 3498 requires that a water heater provides the means to
inhibit the growth of Legionella bacteria in potable water. This water
heater can satisfy this AS 3498 requirement provided it is operating
and the thermostat setting is 60°C or higher, including when it is used
as an in-series booster water heater for a solar water heater.
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 bathing and public areas when this water heater is installed. This will
keep the water temperature below the maximum permitted by AS/NZS 3500.4 to these areas. The risk of
scald injury will be reduced and still allow hotter water to the kitchen, laundry and other areas requiring
sanitising temperatures.
maximum thermostat
setting (82°C)
minimum recommended
stored water temperature
and minimum
thermostat setting
maximum recommended
supply temperature to
bathrooms, ensuites and
public areas

ABOUT YOUR WATER HEATER
5
TEMPERATURE ADJUSTMENT
The water heater features an electronic adjustable thermostat. We recommend only a licensed tradesperson
make any temperature adjustments. We advise the thermostat be adjusted to the lowest temperature setting
that meets your needs, especially if there are young children or elderly people in the premises. Refer to
“Hotter Water Increases the Risk of Scald Injury” on page 4.
ELECTRONIC THERMOSTAT
The thermostat automatically operates the gas control by switching its power on and off, so a constant
temperature is maintained. The thermostat is mounted externally on the water heater and the protective over
temperature cut out is mounted inside the lower front cover of the water heater.
There is no need to switch the water heater off when it is not in use. The thermostat is fully automatic and
only allows the gas control to open when the burner requires gas for heating. The thermostat displays the
current water temperature. To adjust the thermostat settings refer to “Temperature Control” on page 41.
HOT SURFACE IGNITION
The water heater incorporates an automatic burner ignition system. A hot surface igniter (HSI) probe
automatically heats up when the thermostat registers heating of the water is required. When the HSI probe is
fully energised, the gas valve opens allowing gas to the burner which in turn is ignited by the HSI probe.
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 240 V AC electrical power for operation of the control systems and the electrically
operated components. The removal of the access cover(s) will expose 240 V wiring. They must only be
removed by a qualified person.
The water heater is fitted with a power supply cord and plug and must be plugged into a weatherproof
electrical outlet if installed outdoors. Take care not to touch the power plug with wet hands.
SAFETY
If the power supply cord or electrical conduit to the water heater is damaged, it must be replaced by a
qualified person in order to avoid a hazard. The power supply cord and plug must be replaced with a genuine
replacement part available from Rheem. Phone Rheem Service or their nearest Accredited Service Agent to
arrange for an inspection.
This water heater is supplied with a thermostat, an over-temperature cut-out, and 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.
The operation of the over-temperature cut-out on the thermostat indicates a possibly dangerous situation. If
the over-temperature cut-out operates, it must not be reset and the water heater must be serviced by a
qualified person.
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
Do not store flammable or combustible materials near the water
heater. Flammable liquids (such as petrol), newspapers and
similar articles must be kept well away from the water heater and
the draught diverter or flue terminal.
Gases from some aerosol sprays, stain removers and
household chemicals become corrosive when drawn into a
flame. Do not use aerosols and stain removers near the water
heater whilst it is working.
Do not store swimming pool chemicals, household cleaners,
etc., near the water heater.
Do not place anything on top of the water heater or in contact with
the draught diverter or flue terminal. Ensure the flue terminal is not
obstructed in any way at any time.
Do not use Propane / Butane gas mixtures in a Propane model. A Propane model is designed to operate
on Propane only. The use of Propane / Butane mixture, such as automotive LPG fuel, in a Propane
model is unsafe and can cause damage to the water heater.
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. 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 8 and to “Anode Inspection and Replacement” 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.
TO TURN OFF THE WATER HEATER
If it is necessary to turn off the water heater:
Switch off the electrical supply at the isolating switch to the water heater(s).
Close the gas isolation valve(s) at the inlet to the gas control(s).
Close the cold water isolation valve on the cold water line to the water heater(s) to shut down the entire
system, or;
Close the isolation valves on the cold and hot water branches to shut down an individual water heater in
a bank.
TO TURN ON THE WATER HEATER
Open the isolation valves fully on the cold and hot water branches to the water heater(s) installed in a
bank.
Open the cold water isolation valve on the cold water line to the water heater(s). Air will be forced out of
the taps.
Open the gas isolation valve(s) fully at the inlets to the gas control(s).
Switch on the electrical supply at the isolating switch to the water heater(s).

ABOUT YOUR WATER HEATER
7
HOW DO I KNOW THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on pages 17 to 24. The water heater must be installed:
by a qualified person, and
in accordance the installation instructions, and
in compliance with Standards AS/NZS 3500.4, AS 5601 or AS/NZS 5601.1, as applicable under local
regulations, and all local codes and regulatory authority requirements.
In New Zealand the installation must also conform with NZS 5261, as applicable under local regulations, and
the New Zealand Building Code.
VICTORIAN CUSTOMERS
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.
DOES THE WATER CHEMISTRY AFFECT THE 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 11.
If you are in a known harsh water area or you are not sure of your water chemistry, have your water checked
against the conditions described on pages 11 to 13.
HOW LONG WILL THE WATER HEATER LAST?
The water heater is supported by a manufacturer‟s warranty (refer to page 43). 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, the water temperature (inlet and outlet) and the water usage
pattern. Refer to “Precautions” on page 6.

8
REGULAR CARE
MINOR SIX MONTH MAINTENANCE
It is recommended minor maintenance be performed every six months by a responsible officer.
The minor maintenance includes:
Operate the easing lever on the temperature pressure relief valve. It is very important you raise and
lower the lever gently. Refer to “Temperature Pressure Relief Valve” on page 10.
Warning: Exercise care to avoid any splashing of water, as water discharged from the drain line will
be hot. Stand clear of the drain line‟s point of discharge when operating the valve‟s lever.
Operate the easing lever on the expansion control valve (if fitted). It is very important you raise and
lower the lever gently. Refer to “Expansion Control Valve” on page 9.
Check the drain line from the safe tray (if one is installed) is not blocked.
ANNUAL SERVICE
For safe and efficient operation, it is recommended an annual service be conducted on the water heater.
Warning: Servicing of a water heater must only be carried out by qualified personnel. Phone Rheem
Service or their nearest Accredited Service Agent.
Note: The annual service and routine replacement of any components, if required, are not included in the
Rheem warranty. A charge will be made for this work. Only genuine replacement parts should be used on
this water heater.
The annual service includes the following actions:
Inspect and flush the temperature pressure relief valve.
Inspect and flush the expansion control valve (if fitted).
Check and if necessary adjust the inlet gas pressure.
Check the operation of and clean the main burner.
Visually check the unit for any potential problems.
Inspect all connections.
Check the drain line from the safe tray (if one is installed) is not blocked.
Note: The water heater may need to be drained during this service. After the completion of the service, the
water heater will take some time to reheat the water. Hot water may not be available for a while.

REGULAR CARE
9
MAJOR FIVE YEAR SERVICE
It is recommended a major five year service be conducted on the water heater.
Warning: Servicing of a water heater must only be carried out by qualified personnel. Phone Rheem
Service or their nearest Accredited Service Agent.
Note: The five year service and routine replacement of any components, such as the anode and relief
valve(s), are not included in the Rheem warranty. A charge will be made for this work. Only genuine
replacement parts should be used on this water heater.
The major service includes the following actions:
Replace the temperature pressure relief valve.
Inspect and flush the expansion control valve (if fitted). If required, replace the valve.
Inspect and if required, replace the anodes.
If the anodes are not replaced, they should be replaced within three years of this service (refer to
“Anode Inspection and Replacement” on page 12).
Check and if necessary adjust the inlet gas pressure.
Check the operation of and clean the main burner.
Drain and flush the water heater if required.
In commercial applications where large volumes of hot water are used, sediment may build up on the
bottom of the cylinder and reduce the heating efficiency. In extreme cases, particularly in areas of high
water sediment, draining and flushing out may be necessary.
Visually check the unit for any potential problems.
Inspect all connections.
Check the drain line from the safe tray (if one is installed) is not blocked.
Note: The water heater may need to be drained during this service. After the completion of the service, the
water heater will take some time to reheat the water. Hot water may not be available for a while.
EXPANSION CONTROL VALVE
In many areas, including South Australia, Western Australia and scaling water areas, an expansion control
valve is fitted to the cold water line to the water heater. The expansion control valve may discharge a small
quantity of water from its drain line during the heating period instead of the temperature pressure relief valve
on the water heater.
Operate the easing lever on the expansion control valve once every six months. It is very important you
raise and lower the lever gently. The expansion control valve should be checked for performance or
replaced at intervals not exceeding 5 years, or more frequently in areas where there is a high incidence of
water deposits.

REGULAR CARE
10
TEMPERATURE PRESSURE RELIEF VALVE
This valve is near the top of the water heater and is essential for its
safe operation. It is possible for the valve to release a little water
through the drain line during each heating period. This occurs as the
water is heated and expands by approximately 1/50 of its volume.
Continuous leakage of water from the valve and its drain line may
indicate a problem with the water heater (refer to “Temperature
Pressure Relief Valve Running” on page 15).
Warning: Never block the outlet of this valve or its drain line for any
reason.
Operate the easing lever on the temperature pressure relief valve once
every six months. It is very important you raise and lower the lever
gently.
Warning: Failure to do this may result in the water heater cylinder
failing.
Warning: Exercise care to avoid any splashing of water, as water
discharged from the drain line will be hot. Stand clear of the drain line‟s
point of discharge when operating the valve‟s lever.
If water does not flow freely from the drain line when the lever is lifted,
then the water heater must be checked. Phone Rheem Service or their
nearest Accredited Service Agent to arrange for an inspection.
The temperature pressure relief valve should be replaced at intervals
not exceeding 5 years, or more frequently in areas where there is a
high incidence of water deposits (refer to “Water Supplies” on
page 11).
drain
line
lift until water
flows from the
drain line –
lower gently
water
heater

11
WATER SUPPLIES
This water heater must be installed in accordance with this advice to be covered by the Rheem
warranty.
This water heater is manufactured to suit the water conditions of most public reticulated water supplies.
However, there are some known water chemistries which can have detrimental effects on the water heater
and its operation and / or life expectancy. If you are unsure of your water chemistry, you may be able to
obtain information from your local water supply authority. This water heater should only be connected to a
water supply which complies with these guidelines for the Rheem warranty to apply.
CHANGE OF WATER SUPPLY
The changing or alternating from one water supply to another can have a detrimental effect on the operation
and / or life expectation of a water heater cylinder and a temperature pressure relief valve.
Where there is a changeover from one water supply to another, e.g. a rainwater tank supply, bore water
supply, desalinated water supply, public reticulated water supply or water brought in from another supply,
then water chemistry information should be sought from the supplier or it should be tested to ensure the
water supply meets the requirements given in these guidelines for the Rheem warranty to apply.
ANODE
The vitreous enamel lined cylinder of the water heater is only covered by the Rheem warranty when the total
dissolved solids (TDS) content in the water is less than 2500 mg/L and when the correct colour coded anode
is used. If an incorrect colour coded anode is used in the water heater, any resultant faults will not be
covered by the Rheem warranty. In addition, the use of an incorrect colour coded anode may shorten the life
of the water heater cylinder.
The correct colour coded anode must be selected and fitted to the water heater in accordance with the
following advice and the Anode Selection chart on page 11 for the Rheem warranty to apply to the water
heater cylinder.
Total Dissolved Solids
Anode colour code
0 –40 mg/L
Green
40 –150 mg/L
Green or Black
150 –400 mg/L
Black
400 –600 mg/L
Black or Blue
600 –2500 mg/L
Blue
2500 mg/L +
Blue (no cylinder warranty)
The changing of anodes must be carried out by a qualified person.
Note: Some water analysis reports may state the conductivity of the water rather than the level of total
dissolved solids. Conductivity, measured in microsiemens per centimetre (µS / cm), is directly proportional to
the TDS content of the water. TDS, in mg / L, is approximately 70% of the conductivity in µS / cm.
CONDUCTIVITY - µS/cm
TOTAL DISSOLVED SOLIDS & CONDUCTIVITY
(vitreous enamel lined water heater cylinder)
40 150 400 600 TOTAL DISSOLVED SOLIDS (TDS) - mg/L
ANODE SELECTION
warranty applies to a vitreous enamel lined water heater cylinder if the
correct coloured anode is used for the TDS / conductivity level of water
2500
3570
no warranty
applies
to a vitreous
enamel lined
water heater
cylinder
Blue
Black
Green
60 215 570 860
0
0
Blue

WATER SUPPLIES
12
ANODE INSPECTION AND REPLACEMENT
The anodes installed in your water heater will slowly dissipate whilst protecting the cylinder. The life of the
cylinder may be extended by replacing the anodes.
If the anodes are not replaced during a five year service (refer to “Major Five Year Service” on page 9) then
the maximum time after installation when the anodes should be replaced for this water heater is 8 years.
For water supplies which are either softened, desalinated or where the water supply may alternate between
a water tank and a reticulated public supply or another supply, it is recommended the anodes be replaced
within 5 years of installation.
CAUTION
If the water supply has a TDS greater than 150 mg/L and a green anode has not been changed to a black
anode, or if the TDS is greater than 600 mg/L and the anode has not been changed to a blue anode, there is
the possibility the anode may become overactive and hydrogen gas could accumulate in the top of the water
heater during long periods of no use. In areas where this is likely to occur, the installer should instruct the
householder on how to dissipate the gas safely.
If, under these conditions, the water heater has not been used for two or more weeks the following procedure
should be carried out before using any electrical appliances (automatic washing machines and dishwashers)
which are connected to the hot water supply.
The hydrogen, which is highly flammable, should be vented safely by opening a hot tap and allowing the
water to flow. There should be no smoking or naked flame near the tap whilst it is turned on. Any hydrogen
gas will be dissipated. This is indicated by an unusual spurting of the water from the tap. Once the water runs
freely, any hydrogen in the system will have been released.
SATURATION INDEX
The saturation index (SI) is used as a measure of the water‟s corrosive or scaling properties.
In a corrosive water supply, the water can attack copper parts and cause them to fail.
In a scaling water supply calcium carbonate is deposited out of the water onto any hot metallic surface.
Where the saturation index exceeds +0.40, the water is very scaling. An expansion control valve must be
fitted on the cold water line after the non-return valve to protect and for the Rheem warranty to apply to the
temperature pressure relief valve and water heater cylinder.
Water which is scaling may be treated with a water softening device to reduce the saturation index of the
water.
Refer to the Saturation Index chart on page 13.
Refer to the cold water connection detail on page 26 for the position of the expansion control valve.

WATER SUPPLIES
13
-1.0
no warranty applies to a:
temperature pressure relief valve or a
water heater cylinder unless an
expansion control valve is fitted.
SATURATION INDEX (SI)
GAS STORAGE WATER HEATERS
WITHIN WARRANTY
SPECIFICATION
SATURATION INDEX
(calculated @ 80°C water temperature)
+0.4 +0.80
very corrosive very scaling
scaling
corrosive
SUMMARY OF WATER CHEMISTRY ADVICE AFFECTING WARRANTY
The water heater and its components are not suitable for certain water chemistries. Those chemistries are
listed below. If the water heater is connected at any time to a water supply with the following water chemistry,
the Rheem warranty will not cover any resultant faults on the components listed below:
Water Chemistry
Component
Total Dissolved Solids (TDS) > 2500 mg/L
water heater cylinder
Total Dissolved Solids (TDS) not suitable for anode type
water heater cylinder
Saturation Index (SI) > +0.4
(if expansion control valve is not fitted)
water heater cylinder
temperature pressure relief valve

14
SAVE A SERVICE CALL
Check the items below before making a service call. You will be charged for attending to any condition or
fault that is not related to manufacture or failure of a part.
NOT ENOUGH HOT WATER (OR NO HOT WATER)
Is the electricity switched on?
Inspect the isolating switch adjacent to the water heater and ensure it
is turned on.
Is there a time clock on the power supply?
Check the settings on the time clock and ensure they are suitable to
enable heating when it is required.
Is the ignition system ‘locked out’?
Reset the water heater. Refer to “Water Heater Not Operating” on
page 14.
Is a code displayed on the electronic thermostat?
Check the LED display on the electronic thermostat.
If a code is displayed, refer to “Diagnostic Features of Electronic Thermostat” on page 15.
Are you using more hot water than you think?
Are outlets (especially the showers) using more hot water than you think?
Very often it is not realised the amount of hot water used, particularly when showering. Carefully review
the hot water usage.
Have your plumber fit a flow control valve to each shower outlet to reduce water usage.
Temperature pressure relief valve running
Is the relief valve discharging too much water?
Refer to “Temperature Pressure Relief Valve Running” on page 15.
Thermostat setting
Ensure the thermostat setting is appropriate. You may choose to have your electrician adjust the
thermostats upwards to gain additional hot water capacity.
Warning: Hotter water increases the risk of scald injury.
Water heater size
Do you have the correct size water heater for your requirements?
The sizing guide in the Rheem sales literature and on the Rheem website (www.rheem.com.au)
suggests average sizes that may be needed.
WATER HEATER NOT OPERATING
The ignition system may have „locked out‟. To reset the water heater, switch the electrical supply off at the
isolating switch, wait ten seconds then switch on again. If the water heater fails to light, phone Rheem
Service or their nearest Accredited Service Agent to arrange for an inspection.

SAVE A SERVICE CALL
15
DIAGNOSTIC FEATURES OF ELECTRONIC THERMOSTAT
This water heater incorporates an electronic thermostat. In the event of a fault occurring with the thermostat,
a 2-digit code will be displayed.
Code
Fault
E1
Temperature sensor failure
If the fault code is displayed, phone Rheem Service or their nearest Accredited Service Agent to arrange for
an inspection.
BURNER WILL NOT LIGHT
Is the fan in the air duct (631 275 model only) operating continuously?
Ensure the front cover is securely in position. Switch off the electrical supply at the isolating switch, wait
30 seconds and then switch the electrical supply on again. Phone Rheem Service or their nearest
Accredited Service Agent to arrange for an inspection if the water heater burner fails to light.
Is there gas to the water heater?
Check the gas isolation valve on the gas supply line is open.
Is there a normal gas supply to the rest of the premises?
Try lighting another gas appliance. If there is no gas call your gas provider.
Is the ignition system ‘locked out’?
Try resetting the water heater. Refer to “Water Heater Not Operating” on page 14.
TEMPERATURE PRESSURE RELIEF VALVE RUNNING
Normal Operation
It is normal and desirable that this valve allows a small quantity of
water to escape during the heating cycle. However, if the discharge is
deemed excessive (more than 2% of hot water used), there may be
another problem.
Continuous dribble
Try gently raising the easing lever on the relief valve for a few seconds
(refer to “Temperature Pressure Relief Valve” on page 10). This may
dislodge a small particle of foreign matter and clear the fault. Release
the lever gently.
Steady flows for long period (often at night)
This may indicate the mains water pressure sometimes rises above
the designed pressure of the water heater. Ask your installing plumber
to fit a pressure limiting valve.
Warning: Never replace the relief valve with one of a higher
pressure rating.
Heavy flows of hot water until water heater is cold - then stops
until water reheats
The water heater must be switched off at the switchboard. Phone
Rheem Service or their nearest Accredited Service Agent to arrange
for an inspection.
EXPANSION CONTROL VALVE RUNNING
If an expansion control valve is fitted in the cold water line to the water heater (refer to page 26)it may
discharge a small quantity of water instead of the temperature pressure relief valve on the water heater. The
benefit is that energy is conserved as the discharged water is cooler.

SAVE A SERVICE CALL
16
WATER HEATER APPEARS TO BE LEAKING
When the water heater is first lit or after a large usage of hot water, condensation may form on the burner of
the water heater. This is quite normal, especially in winter months and will dry off as the water is heated.
HIGHER THAN EXPECTED GAS BILLS
Should you at any time, feel your gas account is higher than expected, we suggest you check the following
points:
Is the relief valve running excessively?
Refer to “Temperature Pressure Relief Valve Running” on page 15.
Are outlets (especially the showers) using more hot water than you
think?
Refer to “Not Enough Hot Water” on page 14.
Is there a leaking hot water pipe, dripping hot water tap, etc?
Even a small leak will waste a surprising quantity of hot water and gas.
Replace faulty tap washers, and have your plumber rectify any leaking
pipe work.
Has there been an increase in hot water usage?
An increase in hot water usage will result in an increase in water heater operation.
Has your water heating tariff rate been increased by your gas retailer since your previous account?
IF YOU HAVE CHECKED ALL THE FOREGOING AND STILL BELIEVE YOU NEED ASSISTANCE, PHONE
RHEEM SERVICE OR THEIR NEAREST ACCREDITED SERVICE AGENT.

17
INSTALLATION
THIS WATER HEATER IS NOT SUITABLE FOR POOL HEATING.
Check the water heater is suitable for the gas type available.
(refer to the rating label on the water heater)
Note: In Australia, natural gas models can be connected to SNG, however the hourly gas consumption may
be reduced (typically by 10%).
INSTALLATION STANDARDS
The water heater must be installed:
by a qualified person, and
in accordance the installation instructions, and
in compliance with Standards AS/NZS 3500.4, AS 5601 or AS/NZS 5601.1, as applicable under local
regulations, and all local codes and regulatory authority requirements.
In New Zealand the installation must also conform with NZS 5261, as applicable under local regulations, and
the New Zealand Building Code.
All packaging materials must be removed from the water heater prior to its installation. This includes the
removal of the cardboard base of the carton from the underside of the water heater and the protective
packaging from the draught diverter of an indoor model.
WATER HEATER APPLICATION
This water heater is designed for the purpose of heating potable water. Its use in an application other than
this may shorten its life.
If this water heater is to be used where an uninterrupted hot water supply is necessary for the application or
business, then there should be redundancy within the hot water system design. This should ensure the
continuity of hot water supply in the event that this water heater was to become inoperable for any reason.
We recommend you provide advice to the system owner about their needs and building backup redundancy
into the hot water supply system.
Note: AS 3498 requires that a water heater provides the means to inhibit the growth of Legionella bacteria in
potable water. This water heater can satisfy this AS 3498 requirement provided it is operating and the
thermostat setting is 60°C or higher, including when it is used as an in-series booster water heater for a solar
water heater.
WATER HEATER LOCATION
An indoor model must be installed indoors and an outdoor model must
be installed outdoors, except where a 631 275 model water heater is
installed indoors with a room sealed installation kit.
The water heater should be installed either close to the most frequently
used outlets or with a circulated flow and return system and its position
chosen with safety and service in mind. Make sure people (particularly
children) will not touch the flue outlet. The flue terminal must be clear
of obstructions and shrubbery.
Clearance must be allowed for servicing of the water heater. The water
heater must be accessible without the use of a ladder or scaffold.
Make sure the temperature pressure relief valve lever is accessible
and the front covers or panels, thermostats and burner can be
removed for service.
You must be able to read the information on the rating plate. If possible
leave headroom of one water heater height so the anode can be
inspected or replaced. Remember you may have to take the entire
water heater out later for servicing.

INSTALLATION
18
The water heater must not be installed in an area with a corrosive atmosphere where chemicals are stored or
where aerosol propellants are released. Remember the air may be safe to breathe, but when it goes through
a flame, chemical changes take place which may attack the water heater.
For a single water heater installation, follow the diagrams on pages 23 and 24. For multiple water heater
installations, follow the instructions on pages 33 to 36.
INDOOR INSTALLATION
The water heater is to be installed at floor level on a fireproof base and
must stand vertically upright. There are also special requirements in
AS 5601 and AS/NZS 5601.1 for water heaters installed in a garage,
an enclosed space and other locations. Remember all local authorities
have regulations about putting water heaters into roof spaces.
For indoor models the distances set out in the diagram should be
observed. Keep the water heater and flue at least 25 mm clear of
walls, cupboards, timber or any other combustibles and at least
500 mm clear of curtains and furnishings.
Ventilation
The ventilation of a room or an enclosure such as a cupboard, where
the water heater is installed must comply with AS 5601 or
AS/NZS 5601.1.
If the water heater is installed in a room or an enclosure, where the
total thermal input of the water heater and any other gas burning
appliance(s) exceeds 3 MJ / h for each cubic metre of room or
enclosure volume, an adequate air supply must be provided.
For efficient water heater operation allow two permanent openings into
the room or enclosure, each of at least:
66,000 mm2for each 110 MJ model
120,000 mm2for each 200 MJ model
The distance between the top of the upper opening and the ceiling and the distance between the bottom of
the lower opening and the floor must not exceed 5% of the total height of the room or enclosure.
Secondary Flue
A secondary flue must be installed with an indoor water heater to discharge combustion products outside the
building. The flue design and installation must comply with AS 5601 or AS/NZS 5601.1.
The water heater is supplied with a draught diverter, screwed to the top of the water heater. An adaptor is
also supplied with a 621 275 model. The draught diverter is designed to receive a 125 mm diameter
flue (621 265 models) and a 200 mm diameter flue (621 275 models). The flue installed with a 621 275
model sits inside of the adaptor.
Remove the adaptor (621 275 models) from the packaging at the top of the water heater and insert into
the outlet spigot of the draught diverter cone.
The secondary flue must:
be seated inside of the outlet spigot (621 265 models) or the adaptor (621 275 models) of the draught
diverter.
be self supporting and not impose a load on the water heater.
use a slip joint or similar to allow for disconnection.
be designed to run vertically for the maximum possible distance, and not less than 600 mm, before any
change of direction.
There are particular fluing requirements for a 631 275 model water heater installed with a room sealed
installation kit. Refer to the installation instructions supplied with the kit.
Clearance Requirements
Heavy Duty Gas Indoor Water Heaters

INSTALLATION
19
OUTDOOR INSTALLATION
The water heater is to be installed at ground level on a concrete or brick plinth or other fireproof base as
approved by the local authority. The water heater must also stand vertically upright with the back of the water
heater against or within 25 mm of an external wall or alternatively against a fireproof screen extending at
least 500 mm above, below and either side the flue terminal. Failure to observe this precaution can cause
problems in high wind areas. A secondary flue is not required.
The water heater must be located to ensure that the location of the flue terminal complies with the
requirements of AS 5601 or AS/NZS 5601.1, as applicable under local regulations. As a guide the following
requirements are extracted from the Gas Installations Standard. The distances are measured along the wall
behind the water heater.
At least 500 mm between the top of the flue terminal and the
eaves.
At least 500 mm (265) or 1500 mm (275) between the flue
terminal and the edge of any opening into the building, such
as an openable door or window, measured horizontally*.
At least 1000 mm (265) or 1500 mm (275) between the flue
terminal and the edge of any opening into the building, such
as an openable window, measured vertically.
At least 500 mm between the flue terminal and a return wall
or external corner, measured horizontally*.
At least 500 mm clear of any combustibles.
Note: * If these horizontal distances cannot be achieved, AS/NZS 5601.1 states an equivalent horizontal
distance measured diagonally from the nearest discharge point of the flue terminal to the opening may be
deemed to comply. Check with the local regulator.
SAFE TRAY
Where damage to property can occur in the event of the water heater
leaking, the water heater must be installed in a safe tray. Construction,
installation and draining of a safe tray must comply with AS/NZS 3500.4
and all local codes and regulatory authority requirements. AS/NZS 3500.4
also has particular requirements when a safe tray must be installed.
MAINS WATER SUPPLY
Where the mains water supply pressure exceeds that shown in the table below, an approved pressure
limiting valve is required and should be fitted as shown in the installation diagram (refer to installation
diagram on page 26).
Model
265, 275
Relief valve setting
1000kPa
Expansion control valve setting*
850kPa
Max. mains supply pressure
With expansion control valve
680kPa
Without expansion control valve
800kPa
* Expansion control valve not supplied with water heater
TANK WATER SUPPLY
If the water heater is supplied with water from a tank supply and a pressure pump system is not installed,
then the bottom of the supply tank must be at least 1 m above the highest point of the hot water plumbing
system, including the water heater. Care must be taken to avoid air locks. The cold water line to the water
heater should be adequately sized and fitted with a full flow gate valve or ball valve.

INSTALLATION
20
HOT WATER DELIVERY
This water heater can deliver water at temperatures which can cause scalding.
It is necessary and we recommend that a temperature limiting device be fitted between the water heater and
the hot water outlets in any ablution and public areas such as bathrooms, ensuites or public amenities, to
reduce the risk of scalding. The installing plumber may have a legal obligation to ensure the installation of
this water heater meets the delivery water temperature requirements of AS/NZS 3500.4 so that scalding
water temperatures are not delivered to a bathroom, ensuite, or other ablution or public area.
Where a temperature limiting device is installed adjacent to the water heater, the cold water line to the
temperature limiting device can be branched off the cold water line either before or after the isolation valve,
pressure limiting valve and non return valve to the water heater. If an expansion control valve is required, it
must always be installed after the non return valve and be the last valve prior to the water heater.
If a pressure limiting valve is installed on the cold water line to the water heater and the cold water line to a
temperature limiting device branches off before this valve or from another cold water line in the premises,
then a pressure limiting valve of an equal pressure setting may be required prior to the temperature limiting
device.
LEGEND
Two Temperature Zones Using a Temperature Limiting Device