Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Remove the display harness connector from the main PCB
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the DC voltage between each of the points on the main PCB listed below to the earth point on the boiler chassis.
Numbers quoted are counting downwards from the top wire on the display harness connector.
The Voltages should conform approximately to the table below:
Test pointDC Volts
10
2 4.7
321.8
45
524
65