How much does it cost to fix boiler error code 5 flashes red?

Typical repair cost for the boiler 5 flashes red fault is £150-300 including labour.

5 flashes red High

Boiler Fault Code 5 flashes red

Also written as 5FLASHESRED — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 5 flashes red 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's internal computer is experiencing a communication error, meaning it has forgotten its operating settings and cannot safely start up. (As reported on Main Insul 7)

Pick your boiler brand for the 5 flashes red fix

Main 5 flashes red 1 model

Source

Information for the 5 flashes red 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