BoilerFaultCodes 1 green flash High
Boiler Fault Code 1 green flash
Also written as 1GREENFLASH — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1 green flash appears across 2 boiler brands and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has likely detected that it is getting too hot and has paused operation as a safety precaution. (As reported on Baxi 400 Heat)
Pick your boiler brand for the 1 green flash fix
Source
Information for the 1 green flash 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 31 August 2026