Set Appliance State:

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

Observation:

Allow burner to ignite and establish for at least 15 seconds.
Using a flat bladed screwdriver adjust potentiometer P1 on the PCB, clockwise to increase, anticlockwise to decrease.
Can the burner pressure be adjusted to an appropriate level for the system (refer to picture)?