Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
CH Demand
Gas On
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Apply a demand and allow boiler to commence ignition sequence.
Measure the voltage at the gas valve connection across the red and blue wires.
Expect initially 22vdc, dropping to 13vdc
Measure the voltage at the gas valve connection across the red and blue wires.
Expect initially 22vdc, dropping to 13vdc
Isolate as per TOPs P4
and refit as necessary