BoilerFaultCodes 30:0 High
Boiler Fault Code 30:0
Also written as 300 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 30:0 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 has detected an issue with the water pump that moves heat around your radiators and taps, meaning it cannot circulate heat effectively. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 30:0 fix
Source
Information for the 30:0 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