BoilerFaultCodes Lockout light illuminated High
Boiler Fault Code Lockout light illuminated
Also written as LOCKOUTLIGHTILLUMINATED — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Lockout light illuminated 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 stopped working for safety reasons because it either cannot light the flame or the system has become too hot. (As reported on Potterton Puma 100e)
Pick your boiler brand for the Lockout light illuminated fix
Source
Information for the Lockout light illuminated 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