What does the Viessmann Vitodens 100-W F97 fault code mean?
The F97 fault code indicates a problem with the energy optimization feature of the Viessmann Vitodens 100-W boiler. This typically means that the boiler is unable to efficiently adjust its operation to optimize energy use, which can affect overall performance and efficiency.
Common Causes
- Faulty Sensor: A malfunctioning temperature or flow sensor can lead to incorrect readings, causing the energy optimization feature to fail.
- Software Issue: Outdated or corrupted software may prevent the boiler from executing energy optimization functions properly.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves complex boiler functions and potential gas or electrical hazards. Attempting to fix it yourself could lead to safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F97 fault could range from £150 to £300, depending on whether a sensor replacement or software update is required. This cost reflects the need for professional service and the complexity of the issue.