Rheem 871018 Operating instructions

1
SERVICE INSTRUCTIONS
18, 20,24, 26L Integrity
Electronic Gas Continuous Flow
Water Heater
TM031
R
R
Re
e
ev
v
vi
iis s
si
iio o
on
n
n:
:
:
B B
B
P
P
Pu
u
ub
b
bl
lli iis s
sh
h
he
e
ed
d
d:
:
:
F F
Fe
e
eb
b
br
r
ru
u
ua
a
ar
r
ry
y
y
0 0
08
8
8
871018
871020
871024
871024-B
871024-C
871026
871026-B

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
2
Contents
Introduction...................................................................................................................................3
Water Heater Model Identification................................................................................................3
Preset Temperature Adjustment..................................................................................................4
Wiring Diagram - Models with Mechanical Bypass ....................................................................5
Wiring Diagram - Models with Solenoid Operated Bypass........................................................6
Sequence of Operation.................................................................................................................7
Specifications ...............................................................................................................................8
Bypass Operation.........................................................................................................................9
Anti-Frost Heater Circuit ............................................................................................................10
Product Changes........................................................................................................................10
Software Changes ........................................................................................................................10
Parts Replacement & Wiring Changes for 871024, 871024-B & 817026 Model Heaters Only.......10
In-series Gas Boosting...............................................................................................................15
Tempering Valves.......................................................................................................................20
Remote Controllers.....................................................................................................................20
How to Fault Find........................................................................................................................23
Operational Flow Charts 1 & 2...................................................................................................25
Error Codes.................................................................................................................................28
Diagnostic Test Points ...............................................................................................................29
Maintenance Information............................................................................................................30
Clearing Error Code History.......................................................................................................31
Resetting Error Codes................................................................................................................32
Fault Diagnosis Sequence (Fault Finding Chart G)..................................................................33
Fault Finding Chart 1..................................................................................................................34
Fault Finding Chart 2..................................................................................................................36
Fault Finding Chart 3..................................................................................................................38
Fault Finding Chart 3.1...............................................................................................................40
Fault Finding Chart 3.2...............................................................................................................41
Fault Finding Charts 3.3 and 3.5................................................................................................43
Fault Finding Chart 3.6...............................................................................................................44
Fault Finding Chart 3.7...............................................................................................................46
Fault Finding Chart 3.8...............................................................................................................47
Fault Finding Charts 4 and 4.1...................................................................................................48
Fault Finding Chart 4.2...............................................................................................................49
Fault Finding Chart 4.3...............................................................................................................50
Fault Finding Chart 5..................................................................................................................51
Burner Gas Pressure Check.......................................................................................................51
Component Replacement Procedures ......................................................................................52
Exploded View 1 871018 / 871020 / 871024 Replacement Parts List............................................61
Exploded View 2 871018 / 871020 / 871024.................................................................................62
Exploded View 2 871018 / 871020 / 871024 Replacement Parts List............................................63
Exploded View 1 - 871024 Model ...............................................................................................64
Exploded View 2 –871024 Models.............................................................................................66
Exploded View 3 - 871024-B Model............................................................................................68
Exploded View 4 - 871024-B Model............................................................................................70
Exploded View 4 Replacement Parts List - 871024-B Model....................................................71
Exploded View 5 –871024, 871026 & 871026-B Models...........................................................72
Exploded View 6 - 871024-C, 871026 & 871026-B Models........................................................74
Gas Type Conversion Procedure...............................................................................................76
Warranty......................................................................................................................................78

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
3
Safety Warning
The purpose of this service manual is to provide sufficient information to allow a person
with the skills as required by the Regulatory Authorities to carry out effective repairs to a
Rheem Continuous Flow Gas Water Heater in the minimum of time.
Safety precautions or areas where extra care should be observed when conducting tests
outlined in this service manual are indicated by print in bold italics and/or a warning
symbol. Take care to observe the recommended procedure.
Certain diagnostic procedures outlined in these Service Instructions
require “live” testing to be conducted. Personal Protective Clothing (PPE)
shall be worn and an RCD shall be installed between the power point and
3-pin cord of the water heater to reduce the risk of electric shock.
If the supply cord is damaged, it must be replaced by the manufacturer or
its service agent or a similarly qualified person in order to avoid a hazard.
Introduction
The information provided in these instructions is based on the water heater being installed
in accordance with the Installation Instructions provided with each water heater.
Should you require further technical advice on a Rheem Integrity Water Heater, contact
your nearest Rheem Service Department where genuine replacement parts are also
available.
Water Heater Model Identification
The identification numbers are designed to convey detailed information about the water
heater to which it is attached. The model number consists of 6 digits and up to 3 letters.
8
7
1
018
020
024
026
N
F
-B
or
-C
Model Number
8 –Rheem
Location
7 –External
Ignition Type
1 - Electronic 60ºC Max temp
Capacity
Nominal litres/minute @ 25 ºC rise
Gas Type
N - Natural
L - LPG
F - Frost protection fitted
Version
Internal Use Only

4
Preset Temperature Adjustment
It is possible to choose a preset outlet water temperature setting when remote controllers
are not fitted. The water heater comes factory set at 55ºC on 871 series models.
Voltages up to 240 volts will be present within the water heater, take care
not to touch wiring terminals. Use an insulated tool when operating the
DIP switch or MIN and MAX buttons.
To adjust the preset temperature:
1. Remove the front cover from the water heater.
2. Turn DIP SWITCHES 3 and 4 on (up position) on the I.C. Board. The current preset
temperature is displayed on the LED.
3. Press the MIN or MAX button, located under the DIP Switches, until the desired
temperature is displayed. Available temperatures are:
871 series models: 40ºC, 43ºC, 50ºC, 55ºC and 60ºC
4. Turn DIP SWITCHES 3 and 4 off (down position). The temperature display is now
turned off.
5. Refit the front cover to the water heater.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
5
Wiring Diagram - Models with Mechanical Bypass

6
Wiring Diagram - Models with Solenoid Operated Bypass

7
Sequence of Operation
Refer to „Sequence of Operation Component Diagram‟ on page 9 to view components
shown in brackets e.g. (1)
1. When a hot water tap (1) is opened, cold water (or preheated water if a solar preheater
is installed) enters the water heater and passes through the Water Flow Sensor (3) and
Heat Exchanger (19). Note: For 871020, 871024, 871024-B, and 871026 model
heaters fitted with a comparator the inlet water temperature must be less than or equal
to 57ºC and for 871020-B, 871024-C and 871026-B models the inlet water temperature
must be less than or equal to 58ºC and less than or equal to the set point temperature
minus 2ºC for operation to occur past this point; otherwise water will pass straight
through the heat exchanger and fan and burner operation will not occur (for more
information on this subject refer to the section titled „In-series Gas Boosting‟ on page
15).
2. The Water Flow Sensor (3) sends a pulse signal to the PCB (27). Once the pulse
signal reaches a pre designated frequency (at minimum flow rate) the PCB (27)
activates the Fan Motor (25) and the Fan (24) starts rotating.
3. After the Fan (24) completes a pre purge, the Gas Inlet Solenoid Valve (9),Gas
Solenoid Valve 1 (10) and Gas Solenoid Valve 2 (11) open at the same time. The
Proportional Gas Flow Regulating Valve (13) adjusts the gas flow rate to ensure
adequate gas for ignition and gas is then supplied to the Burner (15).
4. At the same time the Gas Solenoid Valves open the Igniter (16) starts sparking
continuously and ignites the gas at the Burner (15). After the flame sensor (18) detects
burner flame, the Proportional Gas Valve (13) begins to control the gas flow rate. If
there is a difference between the hot water temperature detected by the Hot Water
Outlet Thermistor (6) and that set on the water heater or selected on the remote
controller (if fitted) the PCB (27) adjusts the hot water temperature by opening and
closing the Gas Solenoid Valves 1 (10), 2 (11) and 3 (12) and adjusting the
Proportional Gas Flow Regulating Valve (13). The water flow rate is also adjusted via
the Water Flow Servo Motor (7) to ensure the selected temperature of hot water is
delivered.
5. As the gas flow rate, controlled by the Proportional Gas Flow Regulating Valve (13)
changes the PCB (27) varies the speed of the Fan Motor (25) to maintain the correct air
gas mix ratio.
6. When the hot tap (1) is closed, the pulse signal from the Water Flow Sensor (3) stops
and the burner flame is extinguished by closing Gas Solenoid Valves 1 (10), 2 (11), 3
(12) and the Gas Inlet Solenoid Valve (9). The post purge operation then commences.
7. Once the post-purge operation ends (up to 6 minutes) power to the Fan Motor (25) is
cut and the Fan (24) stops.

8
Specifications
Model
871018
871018
871020
871020
871024
871024-B
871024-C
871024
871024-B
871024-C
871026
871026-B
871026
871026-B
Specification
Natural
LPG
Natural
LPG
Natural
LPG
Natural
LPG
Max hourly gas cons.-MJ/Hr
157
157
157
157
188
188
199
199
Min hourly gas cons.-MJ/Hr
24
24
24
24
22
22
19
19
Min inlet wtr pressure-kPa
140
140
140
140
140
140
140
140
Max inlet wtr pressure-kPa
1000
1000
1000
1000
1000
1000
1000
1000
Min inlet gas pressure(kPa)
1.13
2.75
1.13
2.75
1.13
2.75
1.13
2.75
Max inlet gas pressure(kPa)
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
871024
871024-B
871024-C
871024
871024-B
871024-C
Max burner gas test
pressure (kPa)
0.903
1.5
0.903
1.5
0.71
0.912
0.71
1.078
0.965
1.2
Min burner gas test
pressure (kPa)
0.182
0.32
0.182
0.32
0.15
0.17
0.16
0.22
0.17
0.22
Ignition System
Continuous Spark
Power Cons.
(Watts)
Standard
66
66
66
66
64
64
anti-frost*
124
124
124
124
146
146
146
146
Gas connection diam.(mm)
R¾/20
R¾/20
R¾/20
R¾/20
R¾/20
R¾/20
R¾/20
R¾/20
Water connection
diam.(mm)
R½/15
R½/15
R½/15
R½/15
R¾/20
R¾/20
R¾/20
R¾/20
Relief Valve Pressure (kPa)
1750
1750
1750
1750
1750
1750
1750
1750
Accessories
Kitchen Controller
Y
Y
Y
Y
Y
Y
Y
Y
Bathroom 1 Controller
Y
Y
Y
Y
Y
Y
Y
Y
Bathroom 2 Controller
Y
Y
Y
Y
Y
Y
Y
Y
Recess box
Y
Y
Y
Y
Y
Y
Y
Y
Pipe cover
Y
Y
Y
Y
Y
Y
Y
Y
* Maximum power consumption when anti-frost heaters are energised.

9
Sequence of Operation Component Diagram
1
Hot Water Tap
2
Bypass Control Valve
3
Water Flow Sensor
4
Inlet Water Temperature Thermistor
5
Combustion Chamber Thermistor
6
Outlet Water Temperature Thermistor
7
Water Flow Servo Motor
8
Water Filter (Strainer)
9
Gas Inlet Solenoid Valve
10
Gas Solenoid Valve 1
11
Gas Solenoid Valve 2
12
Gas Solenoid Valve 3
13
PGFR Valve
14
Nozzle
15
Burner
16
Igniter
17
Igniter Electrode
18
Flame Sensor
19
Heat Exchanger
20
Over Temperature Limiter
21
Exhaust (Flue) Outlet
22
Combustion Chamber
23
Anti Frost Heater (Models with F in model
number only e.g. 871024NF)
24
Fan
25
Fan Motor
26
Drain Plug With Relief Valve.
27
PCB
Bypass Operation
The bypass is a section of copper pipe work connected between the water body assembly
(effectively the cold water inlet) and the outlet of the heat exchanger and allows a quantity
of cold water to bypass the heat exchanger. The purpose of the bypass is to ensure the
heat exchanger operates at temperatures above the dew point of the combustion gases,
ensuring condensate is not produced, but low enough to maximise the heat exchangers
life. A valve fitted to the water body assembly controls the bypass. There are two types of
bypass valve utilised in the 18, 20 and 24 models. To determine what kind of bypass is
being utilized, compare the appliance to the wiring diagrams on pages 5 & 6.
Mechanical Bypass
The mechanical bypass is a small spring loaded valve located in the water body assembly.
The spring is temperature sensitive, as the cold water temperature decreases the spring
tension increases reducing the amount of cold water flowing through the bypass. The
bypass operates at all times when water is flowing.
Solenoid Operated Bypass
The solenoid operated bypass comprises a valve (located in the water body assembly)
that is controlled by a solenoid (mounted on the water body assembly). The PCB activates
the solenoid at the following predetermined temperatures:
Without Touch Pads: When the unit is preset at 40 or 43 degrees.
With Touch Pads: When temperatures from 37 to 46 degrees are selected.
At all other times the bypass does not operate.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
10
Anti-Frost Heater Circuit
Models with an „F‟ in the model number have an anti frost heater circuit e.g. 871024NF-B.
The anti-frost heaters are wired in series and operate independently from the water heater.
The 18 and 20 litre models have a 58-watt anti-frost system. The 24 and 26 litre models
have an 82-watt anti-frost system.
A thermostat sensing ambient air temperature, positioned in the wiring loom near the
bottom of the water heater, activates the anti-frost heaters when the ambient air
temperature falls to 4ºC +4ºC/-2ºC and deactivates the anti-frost heaters when the
temperature rises above 12ºC.
In the event a heater block becomes open circuit the total heater circuit is rendered
inoperable. The total heater circuit measures 993.2 ohms for the 18 and 20 litre models.
The total heater circuit measures 702.6 ohms for the 24 and 26 litre models.
The circuit is split into two sections with 4 heaters in total. To determine which section has
failed, isolate the power to the water heater and unplug the wiring connectors at the
thermostat, cord set and the water body assembly heater block. The heat exchanger and
hot water outlet heater‟s resistance (3 heater blocks) is 719.2 ohms for the 18 and 20 litre
models and 565.5 ohms for the 24 and 26 litre models. The resistance of the water body
assembly heater is 274 ohms for the 18 and 20 litre models. The resistance of the water
body assembly heater is 137.1 ohms for the 24 and 26 litre models. Refer to Procedure 10
on page 55 for replacement procedure.
Product Changes
Software Changes
18 and 20 litre models manufactured after July 2006 and 24 and 26 litre models
manufactured after May 2006 have a change to the software which controls the operation
of the heater. When an inlet water temperature of more than 58ºC and more than the set
point temperature minus 2ºC is detected by the inlet water temperature thermistor, the fan
and burner will not operate.
This function has been introduced to enhance the operation of the water heater and
remove the need for a Solar Bypass Valve when the Integrity is connected as an in-series
gas booster to a solar water heating system (for more information refer to „In-series Gas
Boosting‟ on page 15).
Models with the revised software have a –B or -C suffix added to the model number i.e.
817020NF-B or 871024NF-C.
Parts Replacement & Wiring Changes for 871024, 871024-B & 817026 Model Heaters
Only
Some parts for 871024, 871024-B & 871026 model heaters have been superseded and
are no longer available (refer to following tables). If any of these superseded parts are
found to be faulty they must be replaced with current parts available for 871024-C and
871026-B model heaters.
Some current parts utilise different wiring connectors/connections necessitating the
replacement of other interconnecting components when installed in 871024, 871024-B and
871026 model heaters (refer to „Parts Replacement Scenarios‟ on page 11). Part numbers
shown in the following tables which are not marked with an asterisk (*) can be considered
a direct replacement and require no additional components or modifications when installed
in 871024, 871024-B and 871026 model heaters.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
11
Note: The parts lists shown on pages 64 - 75 are for current 871026-B and 871024-C
model heaters; superseded part numbers for 871024 and 871026 model heaters are not
shown therein however they are listed in the following tables.
Item
Description
Superseded Model
Current Model
871024
871024-B
871026
871024-C
871026-B
115
Nozzle Plate NG
N/A
31-76238-00
Nozzle Plate LP
N/A
N/A
410
Water Body Assy
31-76285-00
31-76658-00
701
Overheat Limiter
54-02730-00
*31-79562-00
705
Anti-frost heater A
WH0020047
31-71644-00
706
Anti-frost heater B
WH0020048
31-71643-00
712
Thermistor (ambient air)
WH0020052
*Now part of item 758
713
Thermistor Outlet (B)
WH0020181
*20-64774-00
714
Anti-frost thermostat
WH0020054
20-57072-00
715
Thermistor HX
WH0020053
*Now part of item 758
717
Thermistor Inlet (A)
WH0020180
*20-64773-00
723
Hall IC Assy
31-28085-00
*20-43805-00
745
PCB
31-76604-0S
31-76623-0S
757
100V Line Cord
31-23674-00
31-76653-00
758
Signal Loom
WH0020067
*31-76655-00
773
Power Filter
WH0020079
*31-71642-00
780
Power cord
WH0020071
*31-76652-00
783
Transformer
WH0020073
*31-71646-00
784
Connecting Cord
31-23492-00
*31-71641-00
*When installed in 871024, 871024-B and 871026 model heaters these parts will require the replacement of
other interconnecting components. Refer to „Parts Replacement Scenarios‟ on page 11 for more information.
Parts Replacement Scenarios for 871024, 871024-B & 871026 Model Heaters Only
When replacing any of the following parts in 871024, 871024-B or 871026 models heaters
the additional components shown will also require replacing due to wiring/connection
changes between superseded and current parts. In some instances electrical BP
connectors may be utilised instead of replacing the additional listed parts and in
these cases this will be shown as an option. Note: Item numbers refer to the item
number on the exploded views and parts lists located on pages 64 - 75.
Power Cord (item 780)
Old Part Number WH0020071 / New Part Number 31-76652-00
This part may be connected to existing wiring utilising electrical BP connectors otherwise
in addition to the power cord it will also be necessary to replace:
Connecting Cord, Pt Nº 31-71641-00 (item 784)
Transformer, Pt Nº 31-71646-00 (item 783)
Power Filter, Pt Nº 31-71642-00 (item 773)

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
12
Anti-frost heater A, Pt Nº 31-71644-00 (item 705)
Anti-frost heater B, Pt Nº 31-71643-00 (item 706)
Anti-frost thermostat, Pt Nº 20-57072-00 (item 714)
Transformer (item 783)
Old Part Number WH0020073 / New Part Number 31-71646-00
This part may be connected to existing wiring utilising electrical BP connectors otherwise
in addition to the transformer it will also be necessary to replace:
Connecting Cord, Pt Nº 31-71641-00 (item 784)
Power Cord, Pt Nº 31-76652-00 (item 780)
Power Filter, Pt Nº 31-71642-00 (item 773)
Anti-frost heater A, Pt Nº 31-71644-00 (item 705)
Anti-frost heater B, Pt Nº 31-71643-00 (item 706)
Anti-frost thermostat, Pt Nº 20-57072-00 (item 714)
Power Filter (item 773)
Old Part Number WH0020079 / New Part Number 31-71642-00
This part may be connected to existing wiring utilising electrical BP connectors otherwise
in addition to the power filter it will also be necessary to replace:
Connecting Cord, Pt Nº 31-71641-00 (item 784)
Power Cord, Pt Nº 31-76652-00 (item 780)
Transformer, Pt Nº 31-71646-00 (item 783)
Anti-frost heater A, Pt Nº 31-71644-00 (item 705)
Anti-frost heater B, Pt Nº 31-71643-00 (item 706)
Anti-frost thermostat, Pt Nº 20-57072-00 (item 714)
Connecting Cord (item 784)
Old Part Number 31-23492-00 / New Part Number 31-71641-00
This part may be connected to existing wiring utilising electrical BP connectors otherwise
in addition to the connecting cord it will also be necessary to replace:
Power Filter, Pt Nº 31-71642-00 (item 773)
Power Cord, Pt Nº 31-76652-00 (item 780)
Transformer, Pt Nº 31-71646-00 (item 783)
Anti-frost heater A, Pt Nº 31-71644-00 (item 705)
Anti-frost heater B, Pt Nº 31-71643-00 (item 706)
Anti-frost thermostat, Pt Nº 20-57072-00 (item 714)
Ambient Air Thermistor (item 712)
The ambient air thermistor is now part of the signal loom (item 758). In replacing the loom
the connectors on the replacement loom will now not fit any of the thermistors, water flow
sensor or overheat limiter requiring replacement of those items as well.
Old Part Number WH0020052 / New Part Number 31-76655-00 (signal loom)

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
13
In addition to the signal loom it will also be necessary to replace:
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)
Flow Sensor, Pt Nº 20-43805-00 (item 723)
Heat Exchanger Thermistor (item 715)
The heat exchanger thermistor is now part of the signal loom (item 758). In replacing the
loom the connectors on the replacement loom will now not fit any of the thermistors, water
flow sensor or overheat limiter requiring replacement of those items as well.
Old Part Number WH0020053 / New Part Number 31-76655-00 (signal loom)
In addition to the signal loom it will also be necessary to replace:
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)
Flow Sensor, Pt Nº 20-43805-00 (item 723)
Inlet thermistor (item 717)
Old Part Number WH0020180 / New Part Number 20-64773-00
In addition to the inlet thermistor it will also be necessary to replace:
Signal Loom, Pt Nº 31-76655-00 (item 758)
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)
Flow Sensor, Pt Nº 20-43805-00 (item 723)
Outlet Thermistor (item 713)
Old Part Number WH0020181 / New Part Number 20-64774-00
In addition to the outlet thermistor it will also be necessary to replace:
Signal Loom, Pt Nº 31-76655-00 (item 758)
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)
Flow Sensor, Pt Nº 20-43805-00 (item 723)

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
14
Overheat Limiter (item 701)
Old Part Number 54-02730-00 / New Part Number 31-79562-00
In addition to the overheat limiter it will also be necessary to replace:
Signal Loom, Pt Nº 31-76655-00 (item 758)
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Flow Sensor, Pt Nº 20-43805-00 (item 723)
Flow Sensor (item 723)
Old Part Number 31-28085-00 / New Part Number 20-43805-00
This part may be connected to existing wiring utilising electrical BP connectors otherwise
in addition to the flow sensor it will also be necessary to replace:
Signal Loom, Pt Nº 31-76655-00 (item 758)
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)
Signal Loom (item 758)
Old Part Number WH0020067 / New Part Number 31-76655-00
In addition to the signal loom it will also be necessary to replace:
Ambient air thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Heat Exchanger thermistor, now part of the signal loom Pt Nº 31-76655-00 (item 758)
Inlet thermistor, Pt Nº 20-64773-00 (item 717)
Outlet thermistor, Pt Nº 20-64774-00 (item 713)
Flow Sensor, Pt Nº 20-43805-00 (item 723)
Overheat Limiter, Pt Nº 31-79562-00 (item 701)

15
In-series Gas Boosting
Temperature controllers must not be fitted if this water heater is installed
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 pre-heater has been installed to an existing Integrity water heater
installation then a solar bypass valve or a comparator must be fitted at this
water heater and any controllers, if fitted, must be disconnected and
removed. Note: models 871024-C and 871026-B do not require a solar
bypass valve or a comparator.
18 litre Integrity’s are NOT suitable for use as in series gas booster.
871020-B, 871024-C and 871026-B Models
Where one of the above listed model Integrity is installed to provide in-series gas boosting
a solar bypass valve or a comparator is not required. These models have had a change
made to the operating software which eliminates the need for either of these components.
The software now electronically mimics a bypass valve so that when the inlet water
temperature is above 58°C the fan and burner will not operate despite water flowing
through the heat exchanger. When the inlet water temperature is less than or equal to
58°C the burner will fire and boost the outlet temperature to 60°C provided the flow rate is
greater than 3 litres per minute. 20 and 26 models with modified software can be identified
by a B suffix in the model number, whereas a 24 model with modified software can be
identified by a C suffix in the model number i.e. 871024NF-C.
The preset outlet temperature of the Integrity, when installed as an in-series gas booster to
a solar water heater, must be set at 60 C for the system to operate correctly.
The factory preset outlet temperature of all Integrity models is 55 C; during a new
installation it will be necessary to reset the outlet temperature to 60 C. Refer to page 4 for
details on checking and adjusting the outlet temperature.
Note: If a 20, 24, 24B or 26 model heater is replaced with an 20B, 24C or 26B model
heater and the existing 20, 24, 24B or 26 heater is used as an in-line booster and has a
solar bypass valve fitted, the solar bypass valve must be removed and the plumbing
connections remade directly to the Integrity inlet and outlet water connections (refer to
diagrams on pages 15 & 16).
In-series Gas Boosting Integrity Solar Loline Installation
Note: This plumbing diagram is
also applicable to standard
model heaters fitted with a
comparator.
For more information on
comparators refer to page 17.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
16
In-series Gas Boosting
Integrity Solar Hiline
Installation
Note: This plumbing diagram is
also applicable to standard model
heaters fitted with a comparator.
For more information on
comparators refer to page 17.
871020, 871024, 871024-B and 871026 Models
Where one of the above listed models is installed to provide in-series gas boosting, a solar
bypass valve is fitted across the Integrity inlet and outlet water connections to prevent the
water heater from operating when the outlet water temperature from the solar system is
above 57°C (refer to diagrams on page 17). A disconnection union must always be
provided at the solar preheated water inlet and hot water outlet on the solar bypass valve
to allow for removal of the valve.
The solar bypass valve has been specifically designed to work with Rheem Integrity
models listed above. 20 and 26 models ending with a B do not require a bypass valve. 24
models ending with -C do not require a bypass valve. 18 litre Integrity‟s are not suitable
for use as in-series boosters.
The preset outlet temperature of the Integrity, when installed as an in-series gas booster to
a solar water heater, must be set at 60 C for the system to operate correctly.
The factory preset outlet temperature of all Integrity models is 55 C; during a new
installation it will be necessary to reset the outlet temperature to 60 C. Refer to page 4 for
details on checking and adjusting the outlet temperature.
There are two types of solar bypass valves currently in use (Paloma & RMC) and whilst
both operate in the same manner the plumbing arrangement at the valve differs according
to the type of solar bypass valve used (refer to diagrams on page 17). Solar bypass valves
are no longer available and if faulty are to be removed and a Comparator installed. Refer
to pages 17 & 18 for information on comparators.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
17
Note: If a 821020, 821024, 821024-B or 821026 model heater is replaced with an 821020-
B, 821024-C or 821026-B model heater and the existing 871020, 871024, 871024-B or
871026 heater is used as an in-line booster and has a solar bypass valve fitted, the solar
bypass valve must be removed and the plumbing connections remade directly to the
Integrity inlet and outlet water connections (refer to diagrams on pages 15 & 16).
Solar Bypass Valve Operation
When the water temperature entering the solar bypass valve is above 57°C a temperature
sensitive mechanism moves the valve spindle preventing water from entering the Integrity
and allowing the water to flow through the solar bypass valve to the hot water outlet.
If the water temperature from the solar storage tank entering the solar bypass valve is
below 57°C the temperature sensitive mechanism retracts the valve allowing water to
enter the Integrity and preventing flow through the solar bypass valve. The Integrity will
boost the water temperature to 60°C at the hot water outlet provided the flow rate is
greater than 3 litres per minute.
Replacement of Solar Bypass Valve with a Comparator
An electronic device called a Comparator (part number 052127) is
now available to replace the solar bypass valve and is suitable for
use on Rheem 871020, 871024, 871024-B and 871026 models
heaters. NOTE: 20 and 26L models with a B suffix and 24L models
with a C suffix in the model number do not require either a solar
bypass valve or a comparator.
Solar bypass valves are no longer available and if faulty are to be
removed and a Comparator installed. Refer to page 18 for the
procedure on installing a comparator.
The purpose of the comparator is to interrupt the operation of the
burner when the inlet water temperature rises above 57°C.
The comparator is connected to the water flow sensor wiring and the inlet temperature
sensor (cold sensor) wiring; both these components are mounted on the water body within
the gas booster. The comparator monitors the inlet water temperature and when the
temperature rises above 57°C the comparator interrupts the signal from the flow sensor to
the PCB causing the burner to shut down.
Paloma Solar Bypass Valve
RMC Solar Bypass Valve
Inlet water from
solar water heater
Hot water outlet

18
Removing a Solar Bypass Valve and Installing a Comparator
1. Ensure power and water to the water heater is isolated.
2. Remove the front cover (refer to component procedure 1 on
page 52).
3. Locate the 2 pin wiring plug in the wiring loom to the cold
sensor mounted on the water body (refer to fig 1) and
disconnect.
4. Plug the 2 pin male and female connectors from the
comparator into the plugs attached to the cold sensor and the
main wiring loom (refer to fig 2). NOTE: If the comparator
connectors do not fit the cold sensor and main wiring loom
plugs, the model is an 871020-B, 871024-C or 871026-B
model which does not require a comparator.
5. Locate the 3 pin wiring plug in the wiring loom to the flow
sensor (refer to fig 3) and disconnect
6. Plug the 3 pin male and female connectors from the
comparator into the plugs attached to the flow sensor and the
main wiring loom (refer to fig 4).
7. Position and secure the comparator in a safe position using
the existing wiring ties securing the wiring loom (refer to fig
5).
8. Refit the front cover.
9. Remove the bypass valve and associated fittings and connect the inlet and outlet pipe
work directly to the gas booster. NOTE: This may require the pipe work to be
extended; unions must be used at the inlet and outlet to enable removal of the gas
booster for serving if required (refer to diagrams on pages 15 & 16).
10. Restore water and power supplies.
Fig 1
Cold sensor
2 pin cold sensor wiring
plug disconnected
Fig 2
Comparator connected
to cold sensor wiring
Fig 3
3 pin flow sensor wiring
plug disconnected
Fig 4
Comparator connected to
flow sensor wiring
Fig 5
Comparator and wiring
secured in place

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
19
In-series Gas Boosting 871020, 871024, 871024-B & 871026 Solar Loline Installation
Note: For 871020, 871024 & 871024-B and 871026 model heaters fitted with a comparator
refer to diagram on page 15. For more information on comparators refer to page 17.
In-series Gas Boosting 871020, 871024, 871024-B & 871026 Solar Hiline Installation
Note: For 871020, 871024 & 871024-B and 871026 model heaters fitted with a comparator
refer to diagram on page 15. For more information on comparators refer to page 17.

TM031 Integrity 18, 20, 24, 26L Service Instructions REV: B
D.O.I: February 2008
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
20
Tempering Valves
On 871 series models where a tempering valve is fitted and there is not a separate
untempered line for the kitchen or laundry areas, the Kitchen temperature controller will
not be able to display temperatures above 55oC and the delivered water temperature at
the tap will be that set by the tempering valve, which will be no hotter than 55oC.
To enable delivery of hot water at temperatures above 55oC a separate untempered line
must be provided that supplies hot water exclusively to kitchen and laundry areas (refer to
diagram below) and only where no controllers are fitted and 60°C is selected on the preset
temperature adjustment.


Remote Controllers
The Integrity 18, 20, 24 and 26 Litre electronic continuous flow gas water heater can be
fitted with optional remote controllers.
Controller
Type
Bathroom 1
Controller
Bathroom 2
Controller
Kitchen
Controller
Kitchen
Cable 20m
Bathroom
Cable 20m
Code
299854
299855
299853
299856
299857
Other manufacturers‟ controllers cannot be used.
One, two or three controllers can be installed, however if a Bathroom controller is installed
without a Kitchen controller then the maximum selectable hot water temperature will be
limited to 55oC when connected to an 871 series model.
When no hot water is flowing, temperatures can be selected between 37oC and 43oC by
pressing and holding the temperature control buttons, to select temperatures above 43oC
press the temperature control button once for each selection.
A controller must be turned on and must display the „PRIORITY‟ indicator in order to allow
adjustment of water temperature.
When hot water is flowing, the temperature can be increased from 37oC to 43oC only.
The water temperature can be decreased from any setting whether hot water is flowing or
not.