What does the Viessmann Vitodens 100-W F95 fault code mean?
The F95 fault code on the Viessmann Vitodens 100-W indicates a problem with energy distribution, which can affect the boiler’s ability to operate efficiently. This fault typically suggests issues with the heating system’s flow or return temperatures, leading to inadequate heating performance.
Common Causes
- Blocked Heat Exchanger: A blockage in the heat exchanger can restrict water flow, causing the boiler to misread temperature differentials.
- Pump Failure: A malfunctioning circulation pump may fail to distribute hot water effectively throughout the heating system.
Can I fix it myself? (DIY)
It is advisable to call a Gas Safe Engineer for this issue, as it involves complex components and potential gas or electrical hazards. Attempting DIY repairs could lead to safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F95 fault could range from £150 to £300, depending on whether a pump replacement or heat exchanger cleaning is required. This cost reflects the labour and parts needed for professional service.