Boiler Fault Code AL 57

Also written as AL57 — same fault.

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

Fault code AL 57 appears across 1 boiler brand and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has temporarily locked itself because it has detected an unusual temperature reading and needs to recalibrate its internal sensors to work correctly again. (As reported on Sime Brava One HE)