Boiler Fault Code Viessmann boilers

Also written as VIESSMANNBOILERS — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code Viessmann boilers 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 currently operating based on internal settings rather than external controls, meaning it may be ignoring your thermostat or running according to the temperature set on the boiler panel itself. (As reported on Viessmann Vitopend 100)