G.C. Number 41 202 15
Isolate Mains Power to appliance as per TOP's P4

Case removal
Remove plastic Boiler Plinth (1).
Remove two screws (2), hinge forward the case and lift off (3).
Put case in a safe position.
NOTE:
This boiler has no sight glass so the flame cannot be observed.
The boiler cannot be fired with the combustion chamber front removed.
It will be necessary to attach the U-gauge to the boiler to observe gas pressure at the burner during boiler operation.