BoilerFaultCodes d.2 Low
Boiler Fault Code d.2
Also written as D2 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code d.2 appears across 2 boiler brands and 15 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is currently taking a temporary break from heating after successfully reaching its target temperature to prevent it from turning on and off too frequently. (As reported on Vaillant ecoMAX)
Pick your boiler brand for the d.2 fix
Source
Information for the d.2 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