Technical description
Fan turning–speed malfunction (too fast at start–up) | Cause: Fan unit obstructed, plug–in fan connector not correctly inserted, Hall sensor defective, fault in cable loom, defective electronic control system
What causes this fault?
This fault occurs when the boiler’s control board detects that the fan is spinning at an incorrect speed, preventing it from safely clearing waste gases from the system. The most common reason is a mechanical failure within the fan motor or a buildup of dust and debris that hinders its movement. It can also be caused by a communication error where the electronic sensors fail to report the fan's speed accurately to the main computer.
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.