BoilerFaultCodesTechnical description
Lights: On * * Off. Possible causes: Fan wiring continuity fault, fan PCB connection failure, or fan failure.
What causes this fault?
This fault occurs when the boiler's control board tries to start the fan but doesn't receive the correct signal that it is spinning at the right speed. The most common reasons are a build-up of debris causing the fan to seize or an electrical failure within the fan's motor or the main circuit board. Without the fan running correctly, the boiler cannot safely remove exhaust gases, so it shut downs for safety.
This fault is more common in winter, as the fan has to work much harder and for longer periods during cold spells, which can cause older motors 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.