BoilerFaultCodes D.028 Medium
Boiler Fault Code D.028
Also written as D028 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.028 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 having trouble communicating with an external add-on component, such as a remote controller or an extra pump, which is preventing it from operating correctly. (As reported on Vaillant ecoTEC Pro 28)
Pick your boiler brand for the D.028 fix
Source
Information for the D.028 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