Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4

Observation:

With the aid of a torch, thoroughly inspect the inside of the fan and its scroll for:
  •   Restrictions/Blockages.
  •   Dust dirt or cobwebs.
  •   Good general condition.
    Note.
    A new gasket shall be used when the combustion block is refitted.