BoilerFaultCodes 00:3 Low
Boiler Fault Code 00:3
Also written as 003 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 00:3 appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is correctly operating in a specific configuration that manages one heating zone without providing domestic hot water. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 00:3 fix
Source
Information for the 00:3 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 27 April 2026