BoilerFaultCodes Alarm High
Boiler Fault Code Alarm
Also written as ALARM — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Alarm 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 has detected that there is not enough water flowing through the system to operate safely, so it has shut down to protect itself. (As reported on Firebird Envirogreen)
Pick your boiler brand for the Alarm fix
Source
Information for the Alarm 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