BoilerFaultCodes H:01 .05 High
Boiler Fault Code H:01 .05
Also written as H0105 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code H:01 .05 appears across 1 boiler brand and 8 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 leaving it is significantly hotter than the water returning, suggesting a blockage or a problem with how water is circulating around your heating system. (As reported on Baxi Combi 224, 228, 424, 428)
Pick your boiler brand for the H:01 .05 fix
Source
Information for the H:01 .05 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