Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Attach a U-gauge to the gas valve burner pressure test point
Disconnect one the lead from the modulating
solenoid (blue wires) and make safe
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Does the burner light at minimum pressure (refer to table)
Note:
When U-gauge is removed pressure test point
should be tightened & checked for gas soundness.