BoilerFaultCodes D.073 Low
Boiler Fault Code D.073
Also written as D073 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.073 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 is displaying a status notification indicating that the water temperature settings for your hot water comfort mode have been adjusted from their factory default. (As reported on Vaillant ecoTEC Pro 24)
Pick your boiler brand for the D.073 fix
Source
Information for the D.073 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