How much does it cost to fix boiler error code 4 red flashes?

Typical repair cost for the boiler 4 red flashes fault is £250-450 including labour.

4 red flashes High

Boiler Fault Code 4 red flashes

Also written as 4REDFLASHES — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code 4 red flashes appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has stopped working because the fan that helps remove waste gases is either stuck or not communicating with the control board. (As reported on Baxi 400 Heat)

Pick your boiler brand for the 4 red flashes fix

Baxi 4 red flashes 1 model

Source

Information for the 4 red flashes 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 31 August 2026