Rheem 874 Series Technical Document

Owner’s Guide and
Installation Instructions
Gas Continuous Flow Water Heater
27L Gas Water Heater — 874 & 872 Series, 627 Models
This water heater must be installed and serviced by an authorised person.
Please leave this guide with the householder.
INSTALL A RHEEMTM
www.rheem.co.nz

PATENTS
This water heater may be protected by one or more patents or registered designs in the name of
Rheem Australia Pty Ltd or Paloma Co., Ltd.
Rheem New Zealand Pty Ltd is the supplier of the Rheem range of electronic continuous flow gas water heaters,
manufactured by Paloma Co., Ltd, a world leader in water heater technology and manufacture.
TRADEMARKS
® Registered trademark of Rheem New Zealand Pty Ltd.
™ Trademark of Rheem New Zealand 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 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 41.
The other pages are intended for the installer but may be of interest.
Contents....................................................................................................................................... 3
About Your Water Heater............................................................................................................ 4
Temperature Control................................................................................................................... 9
Temperature Control –Standard............................................................................................. 10
Temperature Control –Deluxe................................................................................................. 20
Save A Service Call................................................................................................................... 39
Installation –Water Heater ....................................................................................................... 42
Connections –Electrical........................................................................................................... 55
Ez-Link System Dual Installation............................................................................................. 56
Installation –Controllers .......................................................................................................... 60
Commissioning.......................................................................................................................... 67
Draining The Water Heater ....................................................................................................... 74
Water Supplies........................................................................................................................... 74
Warranty..................................................................................................................................... 75
Water Quality ............................................................................................................................. 75

4
ABOUT YOUR WATER HEATER
MODEL TYPE
The Rheem®electronic continuous flow gas water heater model you have chosen is for outdoor installation
only. This model has an extended warranty (refer to “Warranty”on page 75).
The water heater has a factory preset outlet temperature setting of:
874 series 55 C
872 series 55 C
Notes:
The 874 series water heater may be installed as an in-series gas booster water heater to a solar preheat
water heater. 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.
When installed as a gas booster to a solar preheater, the 874 series water heater:
Can deliver water at temperatures up to 75 C for a Premier Loline system.
During periods of low solar energy gain, will boost the water temperature automatically to a minimum
75 C when required.
The 872 and 874 series water heaters can be used on a recirculation system.
The 872 series water heater can be preset to a maximum temperature of 82˚C.
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 9 to 38). 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.
GAS BOOSTING FOR A SOLAR WATER HEATER
Water stored in the solar storage tank passes through the gas booster
water heater when a hot tap is opened. The gas booster water heater
is for heating water at times of low solar energy gain, such as during
cloudy or rainy weather, or during winter months.
874 SERIES
Solar heated water can reach temperatures up to 75 C for a Premier Loline system. The gas booster water
heater operates automatically. When the solar heated water temperature is 58 C or higher, the flow passes
through the gas booster water heater without boosting. When the solar heated water temperature is below
58 C, the gas booster water heater operates, and heats the water to a minimum temperature of 75 C.
862 SERIES
When the gas booster is set at temperatures up to 75ºC and the water from a solar preheat is within 2ºC of
the gas booster set temperature, the incoming flow passes through the in-series gas booster without
operating. If the water heater is set at 82ºC the temperature difference before the gas booster operates
increases to 4ºC below the set temperature. (i.e. incoming water temperature is <78ºC)

ABOUT YOUR WATER HEATER
5
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 44, 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.
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 9).
If a controller is not installed, the water heater heats the water
to the factory preset outlet temperature setting.
The preset outlet temperature setting is:
874 series 55°C
872 series 55˚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, or a Rheem Service
Centre.
If this water heater is installed as part of a solar water heater
system, the installer has checked and if required, adjusted the
preset outlet temperature setting to:
864 series 75 C
862 Series 70ºC
A tempering valve must be installed as per AS/NZS3500.4 requires you to do so.
Warning: Temperature controllers must not be fitted to this water heater (874 series) as part of a solar
water heater system. This is because the water can be supplied at a temperature much higher than the
controller temperature setting. If a solar preheater 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 75 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.
The factory preset temperature setting of an 874 and 872 series water heaters will not deliver temperatures
exceeding 55 C. There is no requirement in AS/NZS 3500.4 to fit a temperature limiting device unless the
water heater is supplying hot water to an early childhood centre, school, nursing home or a facility for young,
aged, sick or disabled people.
maximum Kitchen controller
temperature setting 874 &
872 series
maximum recommended
supply temperature to
bathrooms and ensuites.
maximum Bathroom
controller temperature setting
874 & 872 series
Minimum Kitchen and
Bathroom controller
temperature setting
maximum temperature 862
series (82ºC)
maximum temperature 864
series (75ºC)

ABOUT YOUR WATER HEATER
6
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.
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 an authorised or
qualified person.
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.
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 an authorised 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 your nearest Rheem Service Centre to arrange for an inspection.
The warranty can become void if relief valves or other safety devices are tampered with or if the
installation is not in accordance with these instructions.
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 flue terminal.
Do not use aerosols, stain removers and household
chemicals near the water heater whilst it is working. Gases
from some aerosol sprays, stain removers and household
chemicals become corrosive when drawn into a flame.
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 flue terminal. Ensure the flue terminal is not
obstructed in any way at any time.
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 7.

ABOUT YOUR WATER HEATER
7
TO TURN OFF THE WATER HEATER
If it is necessary to turn off the water heater:
Turn off the controllers(s) (if fitted) by pressing the on / off button.
The light in the on / off button will go out and the priority light (standard controller) or the ACTIVE light
(Deluxe controller), 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 8
and “Draining the Water Heater”on page 8).
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 light in the on / off button and the priority light (standard controller) or ACTIVE light (Deluxe
controller) will both glow.
The water heater will operate automatically when you open a hot tap.
HOW DO I KNOW IF THE WATER HEATER IS INSTALLED CORRECTLY?
Installation requirements are shown on page 52. The water heater must be installed by an authorised
person. In New Zealand, the installation must comply with Standards AS/NZS 3500.4, NZS 5261 or AS/NZS
5601 and all local codes and regulatory authority requirements.
Warning: Temperature controllers must not be fitted to this water heater (874 series) as part of a solar
water heater system because water at a temperature much higher than the controller setting can be
delivered. If a solar preheater 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 gas booster water heater 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 gas booster water
heater.
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 heat exchanger and fittings. If you are in a known harsh water areayou must
read page 74.If you are not sure, have your water chemistry checked against the conditions described on
page 74.

ABOUT YOUR WATER HEATER
8
HOW LONG WILL THE WATER HEATER LAST?
There are a number of factors that will affect the length of service the water heater will provide. These
include the water chemistry, the water pressure, temperature (inlet and outlet) and the water usage pattern.
However, your water heater is supported by a comprehensive warranty (refer to page 75).
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.
SERVICING
For safe and efficient operation, the water heater should be serviced annually by your nearest Rheem
Service Centre. Only genuine replacement parts should be used on this water heater.
Warning: Servicing of a gas water heater should only be carried out by authorised personnel.
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 warranty (refer to “Warranty Exclusions”on page 76).
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 (to “Draining the Water Heater”on page 74).
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 -20ºC
(including wind chill factor).
Refer to “Warranty Exclusions”on page 76.
DRAINING THE WATER HEATER
Turn off the water heater (refer to “Turn Off The Water Heater”on page 73).
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.

9
TEMPERATURE CONTROL
NOTE: CONTROLLERS MUST NOT FITTED IF WATER TEMPERATURES ABOVE 55ºC ARE REQUIRED
CONTROLLERS
The Rheem 874 and 872 series can be installed with Rheem controllers to enable the user to control the
temperature of the delivered water from the outlet of the water heater. There are two families of Rheem
controllers suitable for installation with this water heater. These are the standard controllers and the Deluxe
controllers.
Standard Controllers
There are three types of standard controller. They are the Kitchen controller (Rheem PN A299850),
Bathroom1 controller (Rheem PN A299851) and the Bathroom2 controller (Rheem PN A299852). The
standard controllers are suitable for use on all 874 and 872 series water heaters.
The standard controllers are identified by a „K‟ (Kitchen controller), „B1‟ (Bathroom1 controller) or „B2‟
(Bathroom2 controller) located on the front bottom left hand corner of the standard controller.
Deluxe Controllers
There are three types of Deluxe controller. They are the Kitchen Deluxe controller (Rheem PN A299861),
Bathroom1 Deluxe controller (Rheem PN A299862) and the Bathroom2 Deluxe controller (Rheem
PN A299863).
The Deluxe controllers are identified by a „K‟ (Kitchen Deluxe controller), „B1‟ (Bathroom1 Deluxe controller)
or „B2‟ (Bathroom2 Deluxe controller), located under the front panel, to the bottom left hand corner adjacent
to the BATH FILL VOLUME label.
The Deluxe controllers offer additional functions to the standard controllers. These are:
An assistance call function, which provides a voice prompt when pressed and will sound on all
controllers. This is useful should a family member require assistance when in the bathroom.
A Bath Fill mode, which is designed to allow the water heater to deliver a selected volume of water at a
selected temperature. Bath filling takes place when the hot tap is opened. When the set volume has
been delivered, the water flow from the water heater ceases. Refer to “Bath Fill Mode” on page 30.
Note: The bath level should be monitored periodically while this function is in use to avoid the possibility
of the bath overflowing. The Bath Fill mode should also be used with caution until you are familiar with
its operation.
Warning: Baths should not be left unattended whenever young children are present.
Warning: Temperature controllers must not be fitted to this water heater (874 series) as part of a solar
water heater system. This is because the water can be supplied at a temperature much higher than the
controller temperature setting. If a solar preheater has been installed to an existing water heater installation,
then all controllers must be disconnected and removed.
Notes:
Where more than one controller is installed, the second or third controller must be of the same family.
A standard controller can only be installed with another standard controller(s) and a Deluxe controller
can only be installed with another Deluxe controller(s). A standard controller(s) and a Deluxe
controller(s) cannot be connected to the same water heater.
One, two or three controllers can be installed. Only one of each type of controller can be connected to
the water heater. Therefore, a maximum of three controllers only can be connected to each water
heater.
A Bathroom2 controller can only be installed if a Bathroom1 controller is installed and a Bathroom2
Deluxe controller can only be installed if a Bathroom1 Deluxe controller is installed.
Other manufacturers‟ controllers are not suitable to and cannot be installed with this water heater.

10
TEMPERATURE CONTROL –STANDARD
STANDARD CONTROLLER FUNCTIONS
If one or more controllers are installed, at least one must be on for the water heater to operate. If all
controllers are off, the water heater will only deliver cold water.
on / off button –This button must be pressed once to turn on the controller.
A controller cannot be turned on if water is flowing from a hot tap.
To turn off a controller, press the on / off button once. The light will go out.
A controller can be turned off whilst water is flowing.
on / off operating light –The light in the on / off button will glow when the controller is turned on.
The light will go out when the controller is turned off.
priority light –This light will glow on a controller when that controller has priority.
The Bathroom controller(s), if they are turned on, have priority over the Kitchen
controller.
Priority means that controller has control of the water heater temperature setting.
The water temperature setting can only be adjusted by the controller that has priority.
in use light –This light will glow on all controllers, whether they are on or off, when hot water is
flowing, regardless of which controller has priority.
display panel –The current temperature setting is displayed on all controllers (whether hot water is
flowing or not), when any controller is on.
If all controllers are off, then the display remains blank.
The water volume can also be displayed on the Kitchen controller. The x10lsymbol
glows when the water volume is displayed.
(up button) –The up button increases the temperature setting (refer to “Temperature Adjustment –
Standard Controller” on page 13).
(downbutton) –The down button decreases the temperature setting (refer to “Temperature
Adjustment –Standard Controller” on page 13).
water volume button (Kitchen controller only) –This feature enables an alarm to sound when a set volume
of water has flowed through the water heater (refer to “Water Volume Function –
Standard Controller” on page 18).
water volume operating light –The light in the water volume button will glow when the water volume button
is pressed and the water volume mode is turned on.
The light will go out when the water volume button is pressed and the water volume
mode is turned off.
water volume symbol –The x10lsymbol below the display panel glows when the water volume mode is
turned on and the water volume is displayed.