Set Appliance State:

CH Demand
Isolate Mains Power to appliance as per TOPs P4
Purge Switch in NORMAL position
HW Switch in OFF position
CH Switch in CH Continuous position
CH Potentiometer set to maximum
Attach a U-gauge to the gas valve outlet pressure test point
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the Fan to operate and the Pilot to ignite.
A positive burner gas pressure should be observed on the U-gauge.
Note:
When U-gauge is removed pressure test point should be tightened & checked for gas soundness.