Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Boiler ON/OFF switch OFF
Attach U-gauge to gas valve outlet pressure test point
Ensure DHW is cold
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Boiler ON/OFF switch ON.
Allow boiler to commence its ignition sequence and ignite.
Observe the U-gauge, does the burner pressure increase to its maximum
(approximately 35.7 mb) after approximately 5 seconds?
Note:
When pressure gauge is removed the pressure test point
should be tightened and checked for gas tightness.