Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
CH Demand
Boiler on/off switch ON
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow the ignition sequence to commence.
During the sparking stage of the ignition cycle measure the voltage across the black and blue leads on the gas valve.
Expected voltage should be greater than 150 Volts DC.
During the sparking stage of the ignition cycle measure the voltage across the black and blue leads on the gas valve.
Expected voltage should be greater than 150 Volts DC.
Isolate as per TOPs P4
and refit as necessary