BoilerFaultCodes D.175 High
Boiler Fault Code D.175
Also written as D175 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.175 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 pump is not moving water around the system correctly, which prevents your radiators or hot water from working properly. (As reported on Vaillant ecoTEC Plus 836)
Pick your boiler brand for the D.175 fix
Source
Information for the D.175 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