db Low

Boiler Fault Code db

Also written as DB — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code db appears across 2 boiler brands 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 is currently operating on a fixed schedule and is not using your room thermostat to adjust its temperature automatically. (As reported on Viessmann Vitodens 222-F)

Pick your boiler brand for the db fix

Unical db 2 models Viessmann db 1 model

Source

Information for the db 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