Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Selector switch to Off
CH temperature selector to Min
DHW temperature selector to Max
Disconnect the electrode leads from the spark electrodes and place through the cover securing screw hole as shown with the lead ends a few millimetres apart
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Selector switch to DHW position.
Keeping clear of the spark leads allow fan to run and ignition sequence to commence.
Can sparking be seen between the ends of the electrode leads?