Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
DHW Demand
Remove the spark electrode cap
Wedge the cap behind the bracket for the spark generator
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Run the appliance and allow the ignition sequence to commence.
Is sparking observed between the cap and the side of the appliance/spark generator bracket during the sparking stage of the cycle?
Note:
The appliance may lockout during this test reset if necessary.
For Guidance on Resetting the Appliance Click Here