d.191 Low

Boiler Fault Code d.191

Also written as D191 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code d.191 appears across 1 boiler brand and 2 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 performing a routine adjustment of its internal startup settings to ensure it lights safely. (As reported on Glow-worm MicraCom)

Pick your boiler brand for the d.191 fix

Glow-worm d.191 2 models

Source

Information for the d.191 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