Set Appliance State:

Mode selector switch to Off/Reset position
Turn Hot Water Tap On
Isolate Mains Power to appliance as per TOPs P4
Hot water temperature control set to maximum
Attach U-gauge to burner pressure test point
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Mode selector switch to DHW position.
Allow burner to ignite and run for at least 1 minute
while observing the burner pressure.
Boiler should run throughout at a maximum
burner pressure of 9.8 mbar +/-1 mbar.
With a DHW demand is the burner pressure satisfactory?
Note:
When U-gauge is removed pressure test point should
be tightened & checked for gas soundness.