Set Appliance State:

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

Measurement:

Measure the voltage across live terminal marked Ls and the neutral terminal marked Ns at the green terminal block on the PCB.
The terminal block is located at the back of the PCB behind the transformer.