What does the Viessmann Vitodens 111-W F94 fault code mean?
The F94 fault code on the Viessmann Vitodens 111-W indicates a problem with the domestic hot water (DHW) calibration. This typically means that the boiler is unable to accurately measure or control the temperature of the hot water being supplied.
Common Causes
- Faulty DHW Sensor: A malfunctioning sensor can lead to incorrect temperature readings, causing calibration issues.
- Control Board Issues: Problems with the control board can affect the calibration process, leading to the F94 fault code being triggered.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair this issue, as it involves gas and electrical components that require professional expertise.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F94 fault code is around £150 to £300, depending on whether the DHW sensor or control board needs replacement. This cost reflects the price of parts and labour for a qualified engineer.