Set Appliance State:
Set Multimeter to AC Volts 
Isolate Mains Power to appliance as per TOPs P4
Gain access to PCB
Use insulation mat where necessary
Gain access to PCB
Use insulation mat where necessary
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across the terminal marked L (live brown wire) and the terminal marked N (neutral blue wire)on the main connector block inside the control box.
Expected voltage 230 volts AC (mains voltage).
Expected voltage 230 volts AC (mains voltage).
Isolate as per TOPs P4
and refit as necessary