What does the Viessmann Vitodens 111-W F38 fault code mean?
The F38 fault code on the Viessmann Vitodens 111-W indicates a malfunction with the water temperature sensor. This issue can prevent the boiler from accurately monitoring and regulating the water temperature, potentially leading to inefficient operation.
Common Causes
- Faulty Temperature Sensor: The sensor may be defective or damaged, causing incorrect readings.
- Wiring Issues: Damaged or loose wiring connections to the sensor can disrupt its functionality.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves electrical components and safety risks. Attempting to fix it without proper training could lead to further damage or safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the water temperature sensor is around £150 to £200. This includes the cost of the part and labour, reflecting the complexity of the repair and the need for a qualified technician.