Technical description
Waiting time deviation: Fan speed. The waiting period for the fan start-up is activated.
What causes this fault?
This fault occurs when the boiler's control system detects that the fan isn't spinning at the precise speed required to safely clear exhaust gases and bring in fresh air. It is often caused by a failing fan motor, a buildup of debris inside the fan, or a communication issue where the main circuit board cannot correctly read the fan's speed. Because the boiler cannot guarantee a safe combustion process, it temporarily pauses operation until the fan speed stabilizes.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.