Set Appliance State:
Gas Off
Set Multimeter to DC Volts 
CH Demand
Isolate Mains Power to appliance as per TOPs P4
External controls calling for heat
CH temperature switch to maximum
DHW temperature switch to minimum
External controls calling for heat
CH temperature switch to maximum
DHW temperature switch to minimum
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage between pins 1 and 2 on connector X6 (red and purple wires)
Expect approximately 25V DC or greater during the sparking stage of the ignition cycle.
Is the voltage measured as expected?
Expect approximately 25V DC or greater during the sparking stage of the ignition cycle.
Is the voltage measured as expected?
Isolate as per TOPs P4
and refit as necessary