BoilerFaultCodes 1 green Low
Boiler Fault Code 1 green
Also written as 1GREEN — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1 green 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 receiving power and has gone into a standby mode because the incoming electrical voltage is too low for it to operate safely. (As reported on Ferroli Combi 77 FF Popular)
Pick your boiler brand for the 1 green fix
Source
Information for the 1 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 27 April 2026