Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Selector Switch in DHW Summer position
Remove Spark Electrode Leads from Spark Electrodes and position as shown
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Ensure the disconnected ends of Electrode Leads close to each other, after approximately 5 seconds can sparking be seen?