Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Selector Switch in CH CONTINUOUS position
Connect a U- Gauge to the Gas Valve outlet pressure test point
Gas On; Pilot On
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Does the Burner ignite and operate at its set burner pressure?
Notes.
CH can be range rated check data badge for settings. Minimum setting is 2.5 mb maximum setting is 15.3 mb.
There will be a delay of between 1 and 3 mins before boiler starts if Power has been switched off or CH demand has been interrupted.
When U-gauge is removed pressure test point should be tightened & checked for gas soundness.