Set Appliance State:

CH Demand
Isolate Mains Power to appliance as per TOPs P4
Mode Selector Switch to CH position (after turning to Lockout/Reset position).
CH Temperature Control to Max
Connect U-gauge to pressure test point on Gas Valve
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Burner pressure should be at a minimum 1.3 mbars.
After approx 2 minutes, burner pressure will slowly start to increase, wait a further minute before slowly reducing the CH Temperature control setting.
Burner pressure should reduce as control is turned down.
Note:
When pressure gauge is removed the pressure test point should be tightened and checked for gas tightness.