How much does it cost to fix boiler error code B, C, D, E & F neons flashing?

Typical repair cost for the boiler B, C, D, E & F neons flashing fault is £150-250 including labour.

B, C, D, E & F neons flashing High

Boiler Fault Code B, C, D, E & F neons flashing

Also written as BCDEFNEONSFLASHING — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code B, C, D, E & F neons flashing 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's safety system has detected an issue with the airflow inside the unit, causing it to shut down to prevent unsafe operation. (As reported on Baxi Combi Instant 80/105 HE)

Pick your boiler brand for the B, C, D, E & F neons flashing fix

Baxi B, C, D, E & F neons flashing 2 models

Source

Information for the B, C, D, E & F neons flashing fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

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