What does the Vaillant ecoTEC plus F35 fault code mean?
The F35 fault code on the Vaillant ecoTEC plus indicates an issue with faulty wiring within the boiler system. This can lead to improper functioning or failure of the boiler to operate correctly.
Common Causes
- Damaged Wiring: Physical damage to the wiring can cause short circuits or disconnections, leading to the F35 error.
- Loose Connections: Poorly connected wires or terminals can result in intermittent faults, triggering the error code.
Can I fix it myself? (DIY)
It is highly recommended to call a Gas Safe Engineer for this issue, as working with electrical components and gas appliances can be dangerous. Attempting DIY repairs may void your warranty and pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F35 fault could be around £150 to £250, depending on the extent of the wiring issues and the parts required. This includes labour costs for a qualified engineer to diagnose and repair the fault.