BoilerFaultCodes d.6 Low
Boiler Fault Code d.6
Also written as D6 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code d.6 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning This code is not actually an error; it is simply showing you the temperature your boiler is currently set to reach for your hot water. (As reported on Vaillant ecoTEC Pro / ecoTEC Plus)
Pick your boiler brand for the d.6 fix
Source
Information for the d.6 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