Set Appliance State:

Mains Power Off
Set Multimeter to AC Voltage Set meter to measure AC Volts
CH Demand
Purge Switch in NORMAL position
HW Switch in OFF position
CH Switch in CH Continuous position
CH Potentiometer set to maximum
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow the Fan to operate and the Pilot to ignite.
Measure the Voltage across the White wire and the Black wire on the Gas Valve Main Solenoid.