BoilerFaultCodes 0A9 High
Boiler Fault Code 0A9
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 0A9 appears across 1 boiler brand and 3 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 electrical fault in the system that controls the gas supply, meaning it cannot safely start up to provide heat or hot water. (As reported on Alpha Pro Tec Plus)
Pick your boiler brand for the 0A9 fix
Source
Information for the 0A9 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 27 April 2026