BoilerFaultCodesTechnical description
FAN RUNNING
What causes this fault?
This fault occurs when the boiler's control board detects the fan is spinning but the air pressure switch fails to close the electrical circuit to confirm safe airflow. The most common reasons are a blockage in the small plastic 'venturi' tubes inside the boiler or a mechanical failure within the pressure switch itself. Without this confirmation signal, the boiler will not spark for ignition as a safety precaution.
This issue is more common during the first cold spell of autumn when a boiler that has been idle over summer is suddenly forced to work at high capacity, causing older mechanical switches to stick.
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.