Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Selector switch set to CH/DHW position
Boiler DHW thermostat set to MAX
Attach pressure gauge to burner pressure test point
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the ignition sequence to commence.
During the sparking phase is at least 4.5 mb of gas present?
Note:
When pressure gauge is removed the pressure test point should be tightened and checked for gas tightness.