D,11 High

Boiler Fault Code D,11

Also written as D11 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

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 struggling to push hot water around your radiators because an external pump is not responding correctly. (As reported on Vaillant ecoTEC)

Pick your boiler brand for the D,11 fix

Glow-worm D,11 7 models Vaillant D,11 38 models

Source

Information for the D,11 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