Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Remove air intake housing (twist and slide down)
Remove bearing plate
(located above the air intake)

Observation:

Inspect the condition of the fan bearing plate ensuring the rubber flaps are complete and not broken off.
Note:
1. Upon reassembly all disturbed joints should be checked
for gas tightness.
2. Before reassembly check the integrity of all disturbed gaskets
and seals and replace as necessary.