Set Appliance State:
Set Multimeter to AC Volts 
Isolate Mains Power to appliance as per TOPs P4
Open the control box by removing the two securing screws and lower the access door
Draw the control board forward to allow access to the PCB
Set boiler control switch to H position
Open the control box by removing the two securing screws and lower the access door
Draw the control board forward to allow access to the PCB
Set boiler control switch to H position
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and boiler to commence its ignition sequence.
Measure the voltage across the gas valve plug connector plug marked J20 (blue and brown wires) on the PCB.
Note:
Voltage is only present for approximately 3 seconds during ignition sequence if burner fails to ignite.
Measure the voltage across the gas valve plug connector plug marked J20 (blue and brown wires) on the PCB.
Note:
Voltage is only present for approximately 3 seconds during ignition sequence if burner fails to ignite.
Isolate as per TOPs P4
and refit as necessary