BoilerFaultCodes High limit thermostat High
Boiler Fault Code High limit thermostat
Also written as HIGHLIMITTHERMOSTAT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code High limit thermostat 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 it has become dangerously hot and has automatically shut itself down to prevent damage, requiring a manual reset. (As reported on Firebird Envirogreen)
Pick your boiler brand for the High limit thermostat fix
Source
Information for the High limit thermostat 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