Boiler Fault Code AL 13

Also written as AL13 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code AL 13 appears across 1 boiler brand and 19 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has shut down because it detected that the smoke and gases leaving the system have become too hot, which is a safety precautionary measure. (As reported on Sime Giulia Combi 30)