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”
Fault Finding Tests 5 – 8
Isolate power before removing connector plugs
Unplug connector B from the PCB and measure
the resistance of the Over Heat Limiter Assembly.
Resistance should be between 50kilo-ohms and
500 kilo-ohms.
Unplug connector K from the PCB. Restore
power and check if error code 79 is displayed
within 30 seconds.
Isolate power when conducting resistance tests. “Live” components
present during voltage tests, exercise caution
Test 8 – Diagnostic points 5, 6, 7 & 8
3y: Water
Inlet
Thermistor
20ºC –
10.3 kilo-
ohms
40ºC –
4.9 kilo-
ohms
4y:
Combustion
Chamber
Thermistor
5y: Hot
Water Outlet
Thermistor
2y: Ambient
Air
Thermistor
25ºC –
5.0 kilo-
ohms
5ºC –
12.7 kilo-
ohms
Use an insulated tool when operating the
DIP switch or MIN and MAX buttons.