Specifications

TM040 16, 18 & 20L Continuous Flow Gas Water Heater Service Instructions
D.O.I: 2/06/2009
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
39
Fault Finding Test 14
Test 14 – Diagnostic Points 5, 6, 7 & 16
3 - Black
12VDC JAPAN
G5NB-1A4 OMRON
T
R
OMRON G5NB-1A4
12VDC JAPAN
OMRON G5NB-1A4
12VDC JAPAN
OMRON G5NB-1A4
12VDC JAPAN
OMRON G5NB-1A4
12VDC JAPAN 12VDC JAPAN
G5NB-1A4 OMRON
Q
5 - Yellow
4 - Red
Isolate power before conducting test.
Using a multimeter set on the ohms scale,
measure the resistance at connector Q whilst
unplugged from the PCB.
Maintenance display code
Diagnostic Point
Test Point
Measured Value
2y: Ambient Air Thermistor
16
7 Blue
3 Black
@20ºC – 10.3 kilo-ohms
@40ºC – 4.9 kilo-ohms
3y: Cold Inlet Thermistor
5
6 White
3 Black
4y: Heat Exchanger Thermistor
6
5 Yellow
3 Black
5y: Hot Water Outlet Thermistor
7
4 Red
3 Black
Error Code 24
Error Code 24
Release the Min/Max buttons and
re-open a hot tap
Is the Min or Max button
depressed?
TEST 16
NO
YES
Replace the PCB
Fault Finding Test 16
Test 16
4321
MAX.MIN.
Ensure the min/max
Are the controller cables or any other
cables/components inadvertently depressing
the Min or Max buttons on PCB?