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 DC volts between the Brown wire on the PCB connector X23 and the neutral at the incoming mains terminal strip, with connector X23 attached to the PCB.
Voltage should be approx 28 vdc.
Voltage should be approx 28 vdc.
Isolate as per TOPs P4
and refit as necessary