BoilerFaultCodes AL 11 High
Boiler Fault Code AL 11
Also written as AL11 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code AL 11 appears across 1 boiler brand and 17 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is unable to control its heat output correctly because a signal wire to the gas burner is broken or detached, causing the system to stop working as a safety precaution. (As reported on Sime Murelle Pro HE 25 HO)
Pick your boiler brand for the AL 11 fix
Source
Information for the AL 11 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