E.01 – .02 High
Boiler Fault Code E.01 – .02
Also written as E0102 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E.01 – .02 appears across 1 boiler brand and 24 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 coming back from your radiators is hotter than the water leaving the boiler, which usually means water is flowing in the wrong direction or a sensor has developed a fault. (As reported on Baxi 200 / 400 Combi)
Pick your boiler brand for the E.01 – .02 fix
Source
Information for the E.01 – .02 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