Set Appliance State:

Mains Power Off
Set Multimeter to DC Volts Set meter to measure DC Volts
Ensure NO Internal or External Controls are Calling for Heat
Remove control box cover
WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure DC voltage across terminals 3 and 5 of the Timer.
Expect approx. 24Vdc across the terminals.