BoilerFaultCodesViessmann 449 Fault Code
The Viessmann 449 fault code means: your boiler's computer system has encountered an internal software timing error that is preventing it from running its startup sequence correctly.. It appears on 1 Viessmann model in our database.
Technical description: Error in scheduled program run monitoring
DIY fix possible
Locate the power button on the front of the boiler control panelPress and hold the reset button (or power off) for at least 5 secondsWait for the boiler to complete its reboot cycle to see if the software clears the error
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Viessmann models that show the 449 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 449 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026