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

Typical repair cost for the boiler 4 flashes red fault is £180-350 including labour.

4 flashes red High

Boiler Fault Code 4 flashes red

Also written as 4FLASHESRED — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 4 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 is having trouble breathing because a part responsible for moving air and fumes is not working correctly, which has caused it to shut down for safety. (As reported on Main Insul 7)

Pick your boiler brand for the 4 flashes red fix

Main 4 flashes red 1 model

Source

Information for the 4 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