Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH/HW switch in HW position
Ensure that the boiler is cold and ready for Pre-heat
Connect a U-gauge to the gas valve outlet pressure point
Boiler On/Off switch ON
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow the boiler to ignite and observe correct gas pressure at approximately 6 mb.
Note:
When U-gauge is removed pressure test point should be tightened & checked for gas soundness.