4 flashes green High

Boiler Fault Code 4 flashes green

Also written as 4FLASHESGREEN — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 4 flashes green 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 is having trouble sending messages between its internal electronic brains, meaning it cannot start the heating or hot water until the connection is restored. (As reported on Baxi EcoBlue Heat)

Pick your boiler brand for the 4 flashes green fix

Baxi 4 flashes green 4 models Main 4 flashes green 1 model Potterton 4 flashes green 1 model

Source

Information for the 4 flashes green 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