Technical description
Fan speed incorrect
What causes this fault?
This fault occurs when the boiler's main control board loses communication with the fan or detects that it isn't spinning at the required speed to safely expel exhaust fumes. The most common reasons are a build-up of dirt inside the fan housing, a loose electrical connection, or a mechanical failure of the fan motor itself.
This fault can sometimes occur during period of high winds if the air pressure prevents the fan from reaching its starting speed, or after a long summer break when moving parts may have seized.
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.