BoilerFaultCodes AL 17 High
Boiler Fault Code AL 17
Also written as AL17 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code AL 17 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 detected that its internal temperature sensors are giving conflicting readings, which stops it from running as a safety precaution. (As reported on Sime Dewy 30/130 HE FS)
Pick your boiler brand for the AL 17 fix
Source
Information for the AL 17 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