All Viessmann error codes
This page brings together Viessmann error codes sorted by type of failure: what each code means, its likely causes, and what you can safely check before calling a professional.
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The Viessmann codes on this page, grouped by type of failure.
Temperature sensor — Viessmann
These codes indicate a sensor that’s no longer returning a consistent value. The problem is almost always the sensor itself or its connector, rarely the unit.
Code F2Medium severityair-to-water
Heating return temperature sensor fault (VF2)
Possible causes
- Faulty VF2 sensor
- Loose connection
What you can check
- Cut power for 30 minutes, then restart
Models affected: Vitocal 100-A, Vitocal 200-A, Vitocal 222-A
This issue requires a qualified technician. Do not open the unit.
Code F3Medium severityair-to-water
Secondary circuit return temperature sensor failure
Possible causes
- Return sensor disconnected
- Sensor cable cut
- Faulty sensor
Models affected: Vitocal 222-A, Vitocal 300-A
This issue requires a qualified technician. Do not open the unit.
All Viessmann codes published on the site
This list updates automatically whenever a new guide is added.
Technical information provided for reference only, based on manufacturer documentation and field feedback. It does not replace the diagnosis of a qualified professional. Found an error on this page? Report it.