BoilerFaultCodes Lockout flame signal High
Boiler Fault Code Lockout flame signal
Also written as LOCKOUTFLAMESIGNAL — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Lockout flame signal appears across 1 boiler brand and 4 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 detect a flame, meaning it is currently unable to safely heat your home or water. (As reported on Halstead Finest Gold)
Pick your boiler brand for the Lockout flame signal fix
Source
Information for the Lockout flame signal 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