BoilerFaultCodes Lockout error High
Boiler Fault Code Lockout error
Also written as LOCKOUTERROR — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Lockout error 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 stopped working safely and needs a simple restart to clear a temporary system error. (As reported on Gledhill GB35C)
Pick your boiler brand for the Lockout error fix
Source
Information for the Lockout error 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