Rheem 864 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 Indoor Water Heater
864, 866 series
627 models
INSTALLER:
The ONLY suitable flue parts are certified Rheem coaxial flue components
carrying the following label:
DO NOT use any other type of flue parts.
Carefully follow the Installation Instructions.
OPERATOR:
DO NOT OPERATE THIS WATER HEATER:
Unless a certified Rheem coaxial flue system, venting to the outside through a certified Rheem
terminal, is installed in accordance with the Installation Instructions.
If a loud continued vibration occurs during operation

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.

3
CONTENTS
HOUSEHOLDER - We recommend you read pages 4 to 44.
The other pages are intended for the installer but may be of interest.
About Your Water Heater............................................................................................................ 4
Temperature Control................................................................................................................. 11
Temperature Control –Standard ............................................................................................. 12
Temperature Control –Deluxe................................................................................................. 22
Water Supplies........................................................................................................................... 41
Save A Service Call................................................................................................................... 42
Installation –Water Heater ....................................................................................................... 45
Connections –Plumbing .......................................................................................................... 57
Flueing........................................................................................................................................ 59
Connections –Electrical........................................................................................................... 76
EZ LINK System Dual Installation............................................................................................ 77
Installation –Controllers .......................................................................................................... 82
Commissioning.......................................................................................................................... 89
Draining The Water Heater ....................................................................................................... 99
Warranty................................................................................................................................... 102
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 864627 models in natural gas and Universal LP Gas fuel types are sold in New Zealand.
References to other models do not apply to the New Zealand market.
The 866 series water heater is not sold in New Zealand.
References to these models do not apply to the New Zealand market.
Universal LP Gas models are not sold in Australia.
References to these models do not apply to the Australian market.

4
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
indoor installation only.
The water heater has a maximum preset outlet temperature setting of:
864 series 75°C
866 series 50°C
Note: The 866 series water heater is marked “THIS APPLIANCE DELIVERS
WATER NOT EXCEEDING 50°C IN ACCORDANCE WITH AS 3498” on the
front panel.
This 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.
MAINS PRESSURE
The water heater is designed for direct connection to the mains water supply. If the mains supply pressure in
your area exceeds that shown on page 47, a pressure limiting valve must be fitted. The supply pressure should
be greater than 140 kPa for the rated flow and performance to be achieved.
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 11 to 40). 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 864 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
5
HOW HOT SHOULD THE WATER BE?
The water heater may be installed with one or more user adjustable temperature controllers, which allow you
to choose the most suitable temperature for your hot water needs (refer to “Temperature Control” on page 11).
If a controller is not installed, the water heater heats the water to the preset outlet temperature setting. The
factory preset outlet temperature setting is:
864 series 60°C –AU 55°C –NZ
866 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 AS 3498 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.
Warning: Temperature controllers must not be fitted to this water heater (864 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 has been 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 864 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 866 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 866 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.
maximum recommended supply
temperature to bathrooms and ensuites.
maximum Bathroom controller
temperature setting 864 series.
maximum Kitchen and Bathroom
controller temperature setting
866 series.
maximum Kitchen controller
temperature setting 864 series.
maximum recommended supply
temperature to bathrooms and ensuites.
maximum Bathroom controller
temperature setting 864 series
minimum Kitchen and Bathroom
controller temperature setting
maximum Kitchen controller
temperature setting 864 series
minimum Kitchen and Bathroom
controller temperature setting

ABOUT YOUR WATER HEATER
6
SAFETY
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.
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 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.
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.
The water heater uses 240 Volt AC electrical power for operation of the control systems and the
combustion fan. The removal of the front panel will expose 240 V wiring. It must only be removed by a
qualified person.
The power lead from the water heater must be plugged into an electrical outlet. Take care not to touch the
power plug with wet hands.
For continued safety of this water heater it must be installed, operated and maintained in accordance with
the Owner’s Guide and Installation Instructions.
Do not modify this water heater.
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 spray aerosols in the vicinity of this water heater while
it is in operation. Gases from many aerosol sprays are
flammable, or may become corrosive when drawn into a flame.
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.
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.
PRECAUTIONS
The water heater must be maintained in accordance with the Owner’s Guide and Installation Instructions. Refer
to “General Maintenance” on page 7, “Minor Maintenance Every Six Months”on page 7 and “Major Service
Every Five Years”on page 7.
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.

ABOUT YOUR WATER HEATER
7
GENERAL MAINTENANCE
The jacket of the water heater can be cleaned with a soft cloth and warm mild soapy water. Under no
circumstances should abrasive materials or powders be used.
Condensate Trap
A condensate trap may be installed as part of a condensate drain line from the secondary flue system.
Regularly check a condensate trap, if one is installed, to ensure it is filled with water. If a trap is dry or the
water level is low, then a trap must be refilled.
To check and / or refill a trap with water, remove the clamp securing the hose of the condensate trap to the
spigot on the flue outlet. Remove the hose from the spigot and fill the condensate trap with water. Reconnect
the hose to the spigot. Ensure the hose is not kinked when reconnected.
Warning: Failure to fill a Condensate Trap with water may cause flue gases to escape through the drain
line.
MINOR MAINTENANCE EVERY SIX MONTHS
It is recommended minor maintenance be performed every six (6) months. Minor maintenance can be
performed by the dwelling occupant.
The minor maintenance includes:
Check the water level in the condensate trap (if one is installed). Refer to “Condensate Trap” on page 7.
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 the water level in the condensate trap (if one is installed).
Check and clean the line strainer.
Visually check the unit for any potential problems.
Inspect all connections.

ABOUT YOUR WATER HEATER
8
CIRCULATED HOT WATER FLOW AND RETURN SYSTEM
A Rheem 864 627 model 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 50 for further
information and notes on this type of installation.
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 9
and “Draining the Water Heater”on page 9).
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.
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 8.
X10L
88
°C
X10L
88
°C

ABOUT YOUR WATER HEATER
9
FROST PROTECTION
The water heater has a frost protection system. The frost protection system will protect the water heater from
damage, by preventing ice forming in the waterways of the water heater, in the event of freezing conditions
occurring.
Notes:
The frost protection system will be rendered inoperable if electrical power is not available at the water
heater. Damage caused by freezing due to the unavailability of power at the water heater is not covered
by the Rheem warranty (refer to “Terms of the Rheem Warranty” on page 102).
If it is necessary to switch the power off to the water heater and there is a risk of freezing, then it is
necessary to drain the water heater (refer to “Draining the Water Heater” on page 9).
Pipe work to and from the water heater must be adequately insulated to prevent freezing.
The water heater is not suitable for installation in areas where the ambient temperature falls below -20°C
(including wind chill factor).
Refer to “Terms of the Rheem Warranty” on page 102.
DRAINING THE WATER HEATER
Turn off the water heater (refer to “Turn Off The Water Heater” on page 8).
Open a hot tap (preferably the shower outlet).
Unscrew the two drain plugs, one each at the cold water inlet and hot water outlet, on the underside of
the water heater.
Water will drain from the water heater.
When water stops flowing from the water heater, close the hot tap.
Note: It is recommended not to screw the drain plugs back in, until the water heater is to be turned on again.

ABOUT YOUR WATER HEATER
10
HOW DO I KNOW IF THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on pages 45 to 56. 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.
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 (864 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 has been 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.
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 41.
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 page 41.
HOW LONG WILL THE WATER HEATER LAST?
The water heater is supported by a manufacturer’s warranty (refer to page 102). 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.