Set Appliance State:

Mains Power Off
Gas Off
Set Multimeter to AC Volts Set meter to measure AC Volts
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure voltage across connection 13 (black lead) and connection 4 (neutral, blue lead) on the control module. Mains voltage should be present.
Measure voltage across connection 14 (white lead) and connection 4 (neutral, blue lead) on the control module. Mains voltage should be absent.