Boiler Fault Code d.11

Also written as D11 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026

Fault code d.11 appears across 2 boiler brands and 45 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is providing an update on the operation of the external pump that helps circulate water through your heating system, though this is often an information code rather than a breakthrough failure. (As reported on Vaillant ecoFIT Pure 418)