Bypass Operation - Rheem 871018 Service Instructions Manual

Sequence of Operation Component Diagram

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. Two types of bypass
valve are utilised in 18 and 20 litre Integrity's.
Mechanical Bypass
Some models without a -B suffix in the model number utilise a mechanical bypass e.g.
871020NF and some models without a -B suffix utilise a solenoid operated bypass. To
determine what kind of bypass is utilised in models without a -B suffix compare the
appliance to the wiring diagrams on pages 6 & 7.
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
Models with a -B suffix in the model number utilise a solenoid operated bypass e.g.
871020NF-B. Some models without a -B suffix also utilise a solenoid operated bypass e.g.
871020NF. To determine what kind of bypass is utilised for models without a -B suffix
compare the appliance to the wiring diagrams on pages 6 & 7.
TM002 Integrity 18 & 20L Service Instructions REV: E
D.O.I: 7/11/2007
This document is stored and maintained electronically by
9
Service. All printed copies not bearing this statement in RED are deemed "uncontrolled"
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
Gas Solenoid Valve 3 (not fitted on 18 &
12
20L models)
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
Anti Frost Heater (Models with F in model
23
number only e.g. 871020NF)
24 Fan
25 Fan Motor
26 Drain Plug With Relief Valve.
27 PCB