What does the Vaillant ecoTEC plus F65 fault code mean?
The F65 fault code on a Vaillant ecoTEC plus boiler indicates a problem with the system calibration, which can affect the boiler’s performance and efficiency. This issue typically arises from incorrect settings or sensor malfunctions that prevent the boiler from operating optimally.
Common Causes
- Incorrect Pressure Settings: If the system pressure is too low or too high, it can lead to calibration issues.
- Faulty Sensors: Malfunctioning temperature or pressure sensors can provide inaccurate readings, causing the boiler to miscalculate its operational parameters.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to address this issue, as it involves complex calibration and potential gas or electrical components that require professional handling.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F65 fault code is around £150 to £250, primarily due to the need for professional diagnostics and potential replacement of faulty sensors or recalibration services.