BoilerFaultCodes ALARM 05 High
Boiler Fault Code ALARM 05
Also written as ALARM05 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code ALARM 05 appears across 1 boiler brand 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 stopped working because it cannot accurately monitor the temperature of the water being heated for your radiators. (As reported on Sime Murelle HE System)
Pick your boiler brand for the ALARM 05 fix
Source
Information for the ALARM 05 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