Set Appliance State:

Turn Hot Water Tap On
Preheat OFF
Ensure boiler is cool
Selector switch in Hot Water position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset boiler if required.
Listen for sparking and observe display on front of boiler.
Flame symbol will appear once burner has lit & established.