Boiler Fault Code Fan On

Also written as FANON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code Fan On appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is operating normally, and this indicator light simply shows that the internal fan is running as expected to vent the system. (As reported on Baxi Solo 3 PFL)