BoilerFaultCodes E01-900 High
Boiler Fault Code E01-900
Also written as E01900 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E01-900 appears across 1 boiler brand and 1 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 a loose or faulty temperature sensor connection, meaning it does not know how hot the water is and has safely shut down to prevent overheating. (As reported on Worcester Bosch 24i RSF)
Pick your boiler brand for the E01-900 fix
Source
Information for the E01-900 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