What does the Viessmann Vitodens 111-W F35 fault code mean?
The F35 fault code on the Viessmann Vitodens 111-W indicates an issue with the gas pressure supply to the boiler. This can lead to insufficient gas flow, affecting the boiler’s ability to operate efficiently and safely.
Common Causes
- Low Gas Pressure: This may occur due to issues with the gas supply line or a malfunctioning gas meter.
- Blocked Gas Supply: Obstructions in the gas line or valves can prevent adequate gas flow to the boiler.
Can I fix it myself? (DIY)
It is highly recommended to call a Gas Safe Engineer to diagnose and resolve gas pressure issues, as working with gas appliances can be dangerous and requires professional expertise.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving a F35 fault could range from £150 to £300, depending on whether the issue is with the gas supply line or requires replacement of components like the gas valve.