BoilerFaultCodes AL 37 High
Boiler Fault Code AL 37
Also written as AL37 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code AL 37 appears across 1 boiler brand and 14 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has stopped working because the electrical power coming into your home from the national grid has dropped to a level that is too low for the boiler to operate safely. (As reported on Sime Halstead Trio)
Pick your boiler brand for the AL 37 fix
Source
Information for the AL 37 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