4 green flashes Low

Boiler Fault Code 4 green flashes

Also written as 4GREENFLASHES — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 4 green flashes appears across 1 boiler brand and 27 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 a temporary 'handshake' issue between its internal electronic brains, but it should fix itself automatically. (As reported on Baxi EcoBlue)

Pick your boiler brand for the 4 green flashes fix

Baxi 4 green flashes 27 models

Source

Information for the 4 green 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 27 April 2026