BoilerFaultCodes dA Medium
Boiler Fault Code dA
Also written as DA — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code dA appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has lost its connection to the indoor temperature sensor for your main heating area, meaning it cannot accurately tell how warm your rooms are. (As reported on Viessmann Vitodens 222-F)
Pick your boiler brand for the dA fix
Source
Information for the dA 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