BoilerFaultCodes D.146 Medium
Boiler Fault Code D.146
Also written as D146 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.146 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has reached its internal limit for how many times the flame-sensing part can be used, and it needs a professional to replace this component to ensure the system remains safe and reliable. (As reported on Vaillant ecoTEC Plus 832)
Pick your boiler brand for the D.146 fix
Source
Information for the D.146 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