Boiler Fault Code neon flashing (Fan runs)

Also written as NEONFLASHINGFANRUNS — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code neon flashing (Fan runs) appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to clear exhaust gases properly because the fan isn't spinning fast enough to vent them safely, so it has stopped working as a precaution. (As reported on Baxi Combi Instant 80/105 HE)