Set Appliance State:

Mains Power Off
On/Off Switch 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 between the top 2 pins (black wires) on connector CN5.
Approximately 24 volts AC should be present.