How much does it cost to fix boiler error code B Flashing?

Typical repair cost for the boiler B Flashing fault is £120-250 including labour.

B Flashing High

Boiler Fault Code B Flashing

Also written as BFLASHING — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code B Flashing appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected that it is getting too hot and has automatically shut down to prevent any damage or safety hazards. (As reported on Alpha CB24)

Pick your boiler brand for the B Flashing fix

Alpha B Flashing 5 models

Source

Information for the B 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 27 April 2026