What does the Vaillant ecoTEC pro F27 fault code mean?
The F27 fault code on a Vaillant ecoTEC pro indicates a malfunction with the flow sensor, which is responsible for measuring the flow of water through the heating system. This issue can lead to the boiler not operating efficiently or failing to heat water properly.
Common Causes
- Blocked Flow Sensor: Debris or limescale buildup can obstruct the flow sensor, causing it to malfunction.
- Electrical Fault: Issues with the wiring or connections to the flow sensor can prevent it from sending accurate readings to the boiler’s control system.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to address this issue, as it involves electrical components and potential gas safety risks. Attempting to fix it yourself could lead to further complications or safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for fixing a faulty flow sensor on a Vaillant ecoTEC pro is around £150 to £200. This includes the cost of the replacement part and labour, reflecting the complexity of the repair and the need for a qualified technician.