Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
Gain access to PCB (use Insulation Mat as required)
Heating temperature selector to OFF
Hot water temperature selector to maximum
Ensure heatbank is not up to temperature (this can be achieved by running the DHW with the mains power to the appliance on and the pilot switched off)
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure voltage across connection 3 (pink wire) on connector X2 and connection 3 (neutral, blue wire) on connector X11 on the PCB.