Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Attach U-gauge to burner pressure test point
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

During the sparking stage of the ignition sequence does the burner pressure increase to approximately 6mb for 8 seconds?
Note:
When "U" gauge is removed test point should be
tightened and checked for gas tightness.