BoilerFaultCodes D.065 High
Boiler Fault Code D.065
Also written as D065 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.065 appears across 1 boiler brand and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has failed to light the flame after several attempts and has switched itself off to prevent a build-up of unburnt gas. (As reported on Vaillant ecoTEC Pro 28)
Pick your boiler brand for the D.065 fix
Source
Information for the D.065 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