What does the Viessmann Vitodens 100-W F31 fault code mean?
The F31 fault code on the Viessmann Vitodens 100-W indicates a problem with the circulation pump, which is responsible for circulating water through the heating system. This fault can lead to insufficient heating and may cause the boiler to shut down to prevent damage.
Common Causes
- Blocked Pump: Debris or sludge in the system can obstruct the pump, preventing it from functioning properly.
- Electrical Fault: Issues with the pump’s electrical connections or the control board can lead to a failure in operation.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for any repairs related to the pump, as dealing with gas and electrical components can be dangerous. However, you can check the boiler pressure and reset the system if necessary.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for fixing the F31 fault, including pump replacement, is around £300 to £450. This includes the cost of the pump and labour, reflecting the complexity of the repair and the need for a qualified technician.