Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Remove connector CN201 from the PCB
Measurement:
Measure for resistance across pins 1 & 2 (pink leads) of connector CN201.
The resistance will vary according to the boiler temperature but should conform approximately to the table below:
The resistance will vary according to the boiler temperature but should conform approximately to the table below:

Isolate as per TOPs P4
and refit as necessary