Isolate Mains Power to appliance as per TOPs P4
Observation:
Remove the air pressure switch tube and inspect the damper restrictor located inside for obstructions and general condition.
Damper restrictor is located at the pressure switch end of the tube.
Refit tube after test.
Damper restrictor is located at the pressure switch end of the tube.
Refit tube after test.
Isolate as per TOPs P4
and refit as necessary