BoilerFaultCodes A90 High
Boiler Fault Code A90
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code A90 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 that the water inside the system is getting much hotter than it should be, so it has shut itself down to prevent damage. (As reported on Vokera Easi-Heat I)
Pick your boiler brand for the A90 fix
Source
Information for the A90 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