BoilerFaultCodes Lockout light constantly on High
Boiler Fault Code Lockout light constantly on
Also written as LOCKOUTLIGHTCONSTANTLYON — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Lockout light constantly on 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 switched itself off to prevent damage after detecting that it is getting too hot inside the unit. (As reported on Worcester Bosch Greenstar 15sbi)
Pick your boiler brand for the Lockout light constantly on fix
Source
Information for the Lockout light constantly on 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