5 flashes red High

Boiler Fault Code 5 flashes red

Also written as 5FLASHESRED — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 5 flashes red appears across 3 boiler brands and 6 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 having difficulty communicating with its main control unit, meaning it cannot process the settings needed to run safely. (As reported on Baxi EcoBlue Advance Heat)

Pick your boiler brand for the 5 flashes red fix

Baxi 5 flashes red 4 models Main 5 flashes red 1 model Potterton 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 7 July 2026