What does the Vaillant F.75 fault code mean?
The Vaillant F.75 fault code indicates that the boiler has detected no pressure rise when the pump starts. This typically suggests an issue with the pump or a blockage in the system preventing water flow.
Common Causes
- Blocked System: A blockage in the heating system can prevent water from circulating, leading to no pressure rise.
- Faulty Pump: If the pump is malfunctioning or has failed, it will not be able to circulate water, resulting in the F.75 fault code.
Can I fix it myself? (DIY)
If you suspect low water pressure, you can check the pressure gauge on your boiler. If it is below 1 bar, you can top up the system using the filling loop. However, if the issue persists or involves the pump or internal components, it is essential to contact a Gas Safe Engineer for assistance.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F.75 fault code can range from £150 to £400. If the pump needs to be replaced, the part itself may cost between £200 and £300, with labor charges of £80 to £120 for installation.