Set Appliance State:
Mains Power Off
Gas Off
Set Multimeter to AC Volts 
Selector Switch in HW position.
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the following voltages:
240V AC across connector M3 connection 17 (Blue wire) and connection 19 (Black wire) on the main PCB.
Approximately 120V AC across connector M3 connection 16 (Brown wire) and connection 17 (Blue wire) on the main PCB.
Approximately 120V AC across connector M3 connection 16 (Brown wire) and connection 19 (Black wire) on the main PCB.
240V AC across connector M3 connection 17 (Blue wire) and connection 19 (Black wire) on the main PCB.
Approximately 120V AC across connector M3 connection 16 (Brown wire) and connection 17 (Blue wire) on the main PCB.
Approximately 120V AC across connector M3 connection 16 (Brown wire) and connection 19 (Black wire) on the main PCB.
Isolate as per TOPs P4
and refit as necessary