Set Appliance State:

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

Measurement:

Apply heating demand, allow fan to start
After 12 seconds voltage should be present at test points. Measure voltage across the black (neutral) pin 5 and red (live) pin 6 on connector J6 on the PCB.
Expected voltage approximately 200V DC
Voltage will only be present for approximately 4 seconds during the ignition phase the appliance will try to ignite a maximum of 5 times before going to lockout.