What does the Viessmann Vitodens 100-W F75 fault code mean?
The F75 fault code on the Viessmann Vitodens 100-W indicates a faulty network connection, which may prevent the boiler from communicating with external devices or the control system. This issue can disrupt the boiler’s operation and may require troubleshooting to restore connectivity.
Common Causes
- Network Cable Issue: A damaged or disconnected network cable can lead to communication failures between the boiler and the control system.
- Faulty Control Board: A malfunctioning control board may fail to process network signals correctly, resulting in the F75 error.
Can I fix it myself? (DIY)
Before attempting any repairs, ensure the boiler is switched off. Check all network cables for damage and ensure they are securely connected. If the issue persists, it is advisable to call a Gas Safe Engineer, as further diagnosis may involve electrical components.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F75 fault could range from £150 to £300, depending on whether a cable replacement or control board repair is necessary. This estimate includes labour and parts, reflecting the complexity of the issue.