Set Appliance State:

Gas On; Pilot On
On/Off Switch ON
Isolate Mains Power to appliance as per TOPs P4
Mode selector switch to Summer
Water thermostat to Max
Connect U gauge to gas valve outlet pressure test point
Hot water tap on

WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Does the U-Gauge indicate high gas rate pressure and the burner ignite to a high flame?
Notes:
The Boiler must not be at its full operating temperature.
When pressure gauge is removed the pressure test point should be tightened and checked for gas tightness.