Boiler Fault Code LLLLL:::::AAAAA

Also written as LLLLLAAAAA — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code LLLLL:::::AAAAA appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage or safety issues. (As reported on Ideal Mexico HE)