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
DHW temperature selector set to MAX
Selector Switch in Hot Water Position
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow burner to ignite and establish.
Adjust the maximum pressure adjustment screw until the burner pressure reads 14.6mb.
(Clockwise to increase, anticlockwise to decrease)
Note:
When U-gauge is removed test point should be checked for gas tightness.