Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Remove control box cover if necessary
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage between the white wire (5th connection up from the bottom) on connector X22 and the neutral at the incoming mains terminal strip, with the connector X22 attached to the PCB.
Expect 5 vdc.
Expect 5 vdc.
Isolate as per TOPs P4
and refit as necessary