Lock---out signal lamp red High
Boiler Fault Code Lock---out signal lamp red
Also written as LOCKOUTSIGNALLAMPRED — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Lock---out signal lamp red 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 is failing to recognise that the flame has lit, causing it to repeatedly try to spark before shutting down for safety. (As reported on Biasi Garda M90f)
Pick your boiler brand for the Lock---out signal lamp red fix
Source
Information for the Lock---out signal lamp red 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