BoilerFaultCodes D.5 Low
Boiler Fault Code D.5
Also written as D5 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.5 appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is displaying a status message to show the temperature it is currently trying to reach for your heating or hot water, rather than being a functional fault code. (As reported on Vaillant ecoTEC)
Pick your boiler brand for the D.5 fix
Source
Information for the D.5 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