Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
Selector switch to Water
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Allow fan to run and ignition sequence to commence.

Does sparking occur at the ignition electrode?
Note:
Ignition electrode is located on the L/H of the burner.