Rheem 812 Series 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
Continuous Flow
Gas Water Heater
874, 876 series
812, 816, T16, 820, 826, T26 models

PATENTS
This water heater may be protected by one or more patents or registered designs in the name of
Rheem Australia Pty Ltd, Rheem New Zealand Limited or Paloma Co., Ltd.
Rheem Australia Pty Ltd and Rheem New Zealand Limited are the suppliers of the Rheem range of continuous flow gas
water heaters, manufactured by Paloma Co., Ltd., a world leader in water heater technology and manufacture.
TRADEMARKS
®Registered trademark of Rheem Australia Pty Ltd., or Rheem New Zealand Limited.
™ Trademark of Rheem Australia Pty Ltd., or Rheem New Zealand Limited.
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 a 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.
HOUSEHOLDER AND INSTALLER PLEASE NOTE
This Owner’s Guide and Installation Instructions is shared for the Australian and New Zealand markets.
Where the content of this document is specific to either market, it is marked with either
AU for Australian specific content or NZ for New Zealand specific content.
The 874816, 874820, 874826 natural gas and Universal LP Gas models
are the only models sold in New Zealand.
References to propane gas models do not apply to the New Zealand market.
The Universal LP Gas models are not sold in Australia.
References to these models do not apply to the Australian market.
The 876 series water heaters are not sold in New Zealand.
References to these models do not apply to the New Zealand market.

3
CONTENTS
HOUSEHOLDER - We recommend you read pages 4 to 46.
The other pages are intended for the installer but may be of interest.
Householder Safety and Warnings............................................................................................ 4
About Your Water Heater............................................................................................................ 6
Temperature Control................................................................................................................. 13
Temperature Control –Standard ............................................................................................. 14
Temperature Control –Deluxe................................................................................................. 24
Water Supplies........................................................................................................................... 43
Save A Service Call................................................................................................................... 44
Installation –Water Heater ....................................................................................................... 47
Connections –Plumbing .......................................................................................................... 61
Connections –Electrical........................................................................................................... 63
EZ LINK System Dual Installation............................................................................................ 65
Installation –Controllers .......................................................................................................... 70
Commissioning.......................................................................................................................... 77
Draining The Water Heater ....................................................................................................... 87
Warranty..................................................................................................................................... 90

4
HOUSEHOLDER –SAFETY AND WARNINGS
It is important you read the following safety and warnings information.
SAFETY AND WARNINGS
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.
If the power supply cord or plug 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 / Centre to arrange for an
inspection.
The power lead from the water heater must be plugged into a weatherproof electrical outlet. Take care
not to touch the power plug with wet hands.
The water heater uses 240 V AC electrical power for operation of the control systems and the combustion
fan. The removal of the front panel will expose 240 V AC wiring. It must only be removed by a qualified
person.
Servicing of the water heater must only be carried out by qualified personnel. Phone Rheem Service or
their nearest Accredited Service Agent / Centre.
This water heater is supplied with temperature sensors, a FlameSafe®protection system and a 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 Rheem warranty may not cover faults if safety devices or the relief valve are tampered with or
if the installation is not in accordance with these instructions.
For continued safety of this water heater it must be installed, operated and maintained in accordance with
the Owner’s Guide and Installation Instructions.
Temperature controllers must not be fitted to this water heater (874 series) if it is installed as an in-series
gas booster with a solar water heater system because water at a temperature much higher than the
controller setting can be delivered. If a solar water heater is installed to an existing water heater
installation, then all controllers must be disconnected and removed.
Do not modify this water heater.
Switch off the electrical supply at the power outlet to the water heater prior to performing general
maintenance. This will prevent the water heater from operating while you clean or spray around the water
heater. Refer to “General Maintenance” on page 9 for additional information.
Do not spray aerosols in the vicinity of this water heater while it is
in operation. Propellants and gases in many aerosol sprays contain
hydrocarbons which are flammable. Gases from aerosol sprays
may also become corrosive when drawn into a flame.
Do not use or store flammable materials in or near this water
heater. Flammable liquids (such as petrol), combustible materials
(such as newspapers) and similar articles must be kept well away
from the water heater and the flue terminal.
Do not store swimming pool chemicals, household cleaners,
etc., near the water heater.
Do not place articles on or against this water heater, or in contact
with the flue terminal. Ensure the flue terminal is not obstructed in
any way at any time.

HOUSEHOLDER –SAFETY AND WARNINGS
5
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 LP gas fuel, in a Propane
model is unsafe and can cause damage to the water heater.
Note: LP gas models sold in New Zealand are designed to operate on the Propane / Butane mixture
supplied in New Zealand. An LP gas model has an LFZ suffix in its model number.
NOTES
Mounting of the water heater –This water heater must be installed vertically upright with the water, gas
and power connections on the underside, pointing toward the ground. The back of the water heater can
be either against a wall or supported by a frame. The water heater must be well secured to the wall or
frame using two fasteners, suitable for the wall or frame type, each at the top and bottom of the unit. Refer
to the note on page 48 for additional information. Alternatively the water heater can be recessed into a
wall, housed in a proprietary made recess box from Rheem.
Mains pressure water supply –The water heater is designed for direct connection to the mains water
supply. The maximum mains water supply pressure for the water heater is 1,000 kPa and the minimum
water supply pressure is 120 kPa. If the mains supply pressure in your area exceeds 1,000 kPa, a pressure
limiting valve must be fitted. A minimum water supply pressure of 120 kPa is required to achieve the rated
flow and performance of the water heater. Refer to “Mains Water Supply” on page 50 for additional
information.
Connection to the water supply –This water heater is intended to be permanently connected to the
water mains and not connected by a hose-set. A braided flexible hose or semi-flexible connector may be
used for connection to the water heater, where permitted by AS/NZS 3500.4.

6
ABOUT YOUR WATER HEATER
WATER HEATER APPLICATION
This water heater is designed for use in a single family domestic dwelling for the purpose of heating potable
water. Its use in an application other than this may shorten its life.
MODEL TYPE
The Rheem®continuous flow gas water heater model you have chosen is
for outdoor installation only.
The water heater has a maximum preset outlet temperature setting of:
874 series 75°C
876 series 50°C
Note: The 876 series water heater is marked “THIS APPLIANCE DELIVERS
WATER NOT EXCEEDING 50°C IN ACCORDANCE WITH AS 3498” on the
front panel.
An 876 series model must not be installed as an in-series gas booster
to a solar water heater, as water temperature greater than 50°C can be
delivered from the water heater contravening its compliance to AS 3498.
WATER HEATER OPERATION
The water heater operates automatically, heating water as it passes through the water heater. When a hot tap
is opened, the gas burners ignite to provide immediate heating of the water. The heat produced by the burner
is transferred to the water through the heat exchanger. The water is heated to a constant temperature by the
automatic adjustment of the gas supply to the burner to suit the water flow rate (refer to “Temperature Control”
on pages 13 to 42). The gas burners extinguish when the hot tap is closed.
Automatic safety controls are fitted to the water heater to provide safe and efficient operation.
REDUCED HOT WATER FLOW WHEN HEAT EXCHANGER IS COLD
At a cold start-up, i.e. when the water heater has not operated for some time (which is most often first thing in
the morning), the initial flow of hot water may be reduced for a period of 5-10 seconds while the heat exchanger
warms up. This is both an energy and water saving feature of this water heater. Once the heat exchanger
has warmed up the hot water flow will increase and remain at normal flow levels. This feature will only occur
at a cold start-up and not when the heat exchanger is already warm from a recent use of hot water.
GAS BOOSTING FOR A SOLAR WATER HEATER
The 874 series water heater may be installed as an in-series gas booster to a solar water heater.
Water stored in the solar storage tank passes through the in-series gas booster when a hot tap is opened. The
in-series gas booster is for heating water at times of low solar energy gain, such as during cloudy or rainy
weather, or during colder months.
The in-series gas booster operates automatically. When the solar heated water temperature is below 58°C,
the in-series gas booster heats the water to its preset outlet temperature setting.
Solar heated water can reach temperatures up to 70°C to 80°C for a Premier Loline and Loline pumped system
and possibly higher for a Hiline and Premier Hiline thermosiphon system. When the solar heated water
temperature is 58°C or higher, the flow passes through the in-series gas booster without boosting.
For information relating to the function and operation of the solar water heater, refer to the Owner’s Guide and
Installation Instructions supplied with the solar water heater.

ABOUT YOUR WATER HEATER
7
USER TEMPERATURE CONTROL
The water heater may be installed with one or more user adjustable temperature controllers, which allow you
to choose the most suitable water temperature for your hot water needs (refer to “Temperature Control” on
page 13).
For an 874 series –NZ or an 876 series water heater, if temperature controllers have not been installed and
where they may not be an ideal option to retrofit to your water heater installation, the Rheem EZiSETTM system
is an alternative temperature control system. The Rheem EZiSET allows you to control the water temperature
and bath water levels directly from your Smartphone. An appropriately licensed tradesperson must firstlyinstall
the Rheem EZiSET control module into your water heater and a PLT adaptor (supplied in the EZiSET kit) must
also be connected to your Wi-Fi modem before you download the free app onto your Smartphone. No
additional wiring is required.
For further information, visit AU –www.rheem.com.au/Continuous-Flow-Accessories, or NZ –
www.rheem.co.nz/gas-water-heaters/.
Note –The Rheem EZiSET system:
is suitable for a single water heater installation only.
cannot be used on the 874 series –NZ or an 876 series water heaters if two of these water heaters are
installed with the Rheem EZ Link system, or if multiple water heaters are manifolded together.
is not suitable for installation on an 874 series –AU water heater.
HOW HOT SHOULD THE WATER BE?
If a controller or EZiSET system is not installed, the water heater heats the water to the preset outlet
temperature setting. The factory preset outlet temperature setting is:
874 series 60°C –AU 55°C –NZ
876 series 50°C
Note: The preset outlet temperature setting of this water heater cannot be adjusted by the householder. The
setting can only be adjusted by the installer, Rheem Service or their nearest Accredited Service Agent / Centre.
Australia New Zealand
Note:Australian Standard AS 3498 and New Zealand Building Code Clause G12 requires that a water heater
provides the means to inhibit the growth of Legionella bacteria in potable water. When this water heater is
used as an in-series booster for a solar water heater it can satisfy these AS3498 and Clause G12 requirements
provided it is energised, the booster preset outlet temperature setting is 70°C, and that a remote temperature
controller is not used.
maximum recommended supply
temperature to bathrooms and ensuites.
maximum Bathroom controller
temperature setting 874 series.
maximum Kitchen and Bathroom
controller temperature setting
876 series.
maximum Kitchen controller
temperature setting 874 series.
maximum recommended supply
temperature to bathrooms and ensuites.
maximum Bathroom controller
temperature setting 874 series
minimum Kitchen and Bathroom
controller temperature setting
maximum Kitchen controller
temperature setting 874 series
minimum Kitchen and Bathroom
controller temperature setting

ABOUT YOUR WATER HEATER
8
Warning: Temperature controllers must not be fitted to this water heater (874 series) if it is installed as an
in-series gas booster with a solar water heater system because water at a temperature much higher than the
controller setting can be delivered. If a solar water heater is installed to an existing water heater installation,
then all controllers must be disconnected and removed.
If this water heater is installed as part of a solar water heater system, the system can deliver water at
temperatures from 58°C up to 80°C and possibly higher depending upon the model of solar water heater
installed.
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 be required by regulations that an approved temperature limiting device be fitted
into the hot water piping to the bathroom and ensuite when an 874 series water heater is installed. This will
keep the water temperature below 50°C –AU or 55°C –NZ at the bathroom and ensuite. The risk of scald
injury will be reduced and if no controllers are installed and the preset outlet temperature setting has not been
adjusted below 55°C or if a Kitchen controller is installed, still allow hotter water to the kitchen and laundry.
An 876 series water heater will not deliver temperatures exceeding 50°C, in accordance with AS 3498. There
is no need to fit a temperature limiting device to satisfy the requirements of AS/NZS 3500.4, if an 876 series
water heater is installed in an application where 50°C is the maximum permissible hot water temperature at
the outlet of a sanitary fixture used primarily for personal hygiene purposes.
HOW DO I KNOW IF THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on pages 47 to 60. 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, and either AS 5601 or AS/NZS 5601.1 as applicable under
local regulations, and all local codes and regulatory authority requirements.
The Gas installations Standards AS 5601 and AS/NZS 5601.1 place limitations on the location of a gas
water heater within a covered area. Refer to “Installation within a Covered Area” on page 49.
In New Zealand, the installation must conform to Clauses G11, G12 and H1 of the New Zealand Building Code.
Warning: Temperature controllers must not be fitted to this water heater (874 series) if it is installed as an
in-series gas booster with a solar water heater system because water at a temperature much higher than the
controller setting can be delivered. If a solar water heater is installed to an existing water heater installation,
then all controllers must be disconnected and removed.
The pipe work between the solar storage tank (if one is installed) and the in-series gas booster has a minimum
recommended pipe size of DN20, MUST BE of copper and be fully insulated in accordance with the
requirements of AS/NZS 3500.4. The insulation must be weatherproof and UV resistant if exposed. The
insulation must be fitted up to the connections on both the solar storage tank and the in-series gas booster.
PRECAUTIONS
The water heater must be maintained in accordance with the Owner’s Guide and Installation Instructions. Refer
to “General Maintenance” on page 9 and “Major Service Every Five Years”on page 9.
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 a plumber or specifier about your needs and building back-up
redundancy into your hot water supply system.

ABOUT YOUR WATER HEATER
9
GENERAL MAINTENANCE
General maintenance can be performed by the dwelling occupant. It is recommended general maintenance
be conducted every six (6) months or as required.
Switch off the electrical supply at the power outlet to the water heater prior to performing general maintenance.
This will prevent the water heater from operating while you clean or spray around the water heater. Switch on
the electrical supply at the power outlet to the water heater when finished performing the general maintenance.
The general maintenance includes:
If required the jacket of the water heater can be cleaned with a soft cloth and warm mild soapy water if
required. Under no circumstances should abrasive materials or powders be used.
Inspect around the air inlet, flue terminal and the water heater in general for plant growth.
Trim back any shrubs, bushes or other plants which have encroached around the water heater.
Plant growth across the air inlet and flue terminal can interfere with the performance of the water
heater.
Inspect around the water heater for infestations of insects, such as ants. Insects encroaching into or
nesting in the water heater can interfere with the operation of the water heater and also damage
components. The area around the water heater can be sprayed with insecticide to rid the area of insects.
Warning: Do not spray insecticide near the water heater while it is operating. Propellants in many
insect sprays contain hydrocarbons which are flammable. Gases from aerosol sprays may also become
corrosive when drawn into a flame.
If necessary to rid the area of insects:
Ensure the electrical supply at the power outlet to the water heater has been switched off.
Spray the affected are, taking care not to spray into the air inlet or flue terminal or onto the surface
of the water heater.
Wait a few minutes to allow any aerosol gases to dissipate before switching on the electrical
supply at the power outlet to the water heater.
MAJOR SERVICE EVERY FIVE YEARS
For safe and efficient operation, it is recommended a major service be conducted on the water heater every
five (5) years.
Warning: Servicing of a water heater must only be carried out by qualified personnel. Phone Rheem
Service or their nearest Accredited Service Agent / Centre.
Note: The major 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 major service includes the following actions:
Check and if necessary adjust the gas pressure.
Check the operation of and clean the burner.
Check and clean the line strainer.
Visually check the unit for any potential problems.
Inspect all connections.

ABOUT YOUR WATER HEATER
10
TO TURN OFF THE WATER HEATER
If it is necessary to turn off the water heater:
Turn off the controller(s) (if fitted) by pressing the on / off ( ) button.
The on / off operating light will go out and the priority light, if it is on, will go out.
Switch off the electrical supply at the power outlet to the water heater if there is no risk of freezing
conditions occurring (refer to note below).
Close the gas isolation valve at the inlet to the water heater.
Close the cold water isolation valve at the inlet to the water heater.
Note: If there is a risk of freezing conditions, the electrical supply to the water heater should not be switched
off unless the water heater is drained, otherwise damage could result (refer to “Frost Protection”on page 11
and “Draining the Water Heater”on page 11).
TO TURN ON THE WATER HEATER
Screw in the drain plugs at the cold water inlet and hot water outlet of the water heater if the water heater
has been drained.
Open all of the hot taps in the house (don’t forget the shower).
Open the cold water isolation valve fully at the inlet to the water heater.
Air will be forced out of the taps.
Close each tap as water flows freely from it.
Open the gas isolation valve fully at the inlet to the water heater.
Plug in the power supply cord at the power outlet.
Switch on the electrical supply at the power outlet to the water heater.
Turn on a controller, if one is fitted, by pressing the on / off ( ) button.
The on / off operating light and the priority light will both glow.
The water heater will operate automatically when you open a hot tap.
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A Rheem 874 series continuous flow water heater can be installed as part of a circulated hot water flow and
return system in a building. Refer to “Circulated Hot Water Flow and Return System” on page 53 for further
information and notes on this type of installation.
GOING ON HOLIDAYS
If you are going on holidays, it is not necessary to turn the water heater off. If it is necessary to turn off the
water heater, refer to “To Turn Off The Water Heater” on page 10.
X10L
88
°C
X10L
88
°C