Set Appliance State:

Mains Power Off
Set Multimeter to DC Volts Set meter to measure DC Volts
CH Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

During the sparking stage of the ignition cycle measure the DC voltage between pin 8 (Red) on connector X25 and a suitable earth.
Expect approximately 17-22 Vdc.
Note:
Each pin on the PCB connector is numbered.