BoilerFaultCodesTechnical description
FAN RUNNING
What causes this fault?
This fault occurs when the boiler's internal computer detects that the fan is spinning, but the safety sensor fails to confirm that air is actually moving through the system. The most common reason is a sticking air pressure switch or a fan that has become sluggish due to a build-up of dirt and debris over time. Because the boiler cannot guarantee that harmful exhaust fumes are being safely pushed outside, it shuts down as a safety precaution.
This issue often surfaces during the first cold spell of autumn when a boiler that has been idle over summer is suddenly asked to work at full capacity, causing weakened components like the fan or pressure switch to fail.
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.