Set Appliance State:
Mains Power Off
Set Multimeter to AC Voltage 
Turn Hot Water Tap On
Gas On
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and ignition sequence to commence and burner to ignite and establish.
Measure the voltage across black and white wires at the gas valve.
Expect voltage of approximately 35v AC or greater.
Is the voltage measured as expected?
Measure the voltage across black and white wires at the gas valve.
Expect voltage of approximately 35v AC or greater.
Is the voltage measured as expected?
Isolate as per TOPs P4
and refit as necessary