BoilerFaultCodes AL 30 High
Boiler Fault Code AL 30
Also written as AL30 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code AL 30 appears across 1 boiler brand and 6 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 an issue with the sensor that monitors water returning from your radiators, causing the system to stop working as a safety precaution. (As reported on Sime Giulia Combi 30)
Pick your boiler brand for the AL 30 fix
Source
Information for the AL 30 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