What does the Vaillant ecoTEC plus F57 fault code mean?
The F57 fault code indicates a problem with the system expansion vessel, which is responsible for maintaining pressure within the heating system. This fault can lead to pressure fluctuations and may affect the overall performance of the boiler.
Common Causes
- Defective Expansion Vessel: The expansion vessel may be faulty or have lost its charge, preventing it from effectively absorbing pressure changes.
- Pressure Loss: A significant drop in system pressure can cause the expansion vessel to malfunction, often due to leaks in the system.
Can I fix it myself? (DIY)
It is advisable to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that require professional handling. Attempting to fix it yourself could pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F57 fault is around £200 to £300, primarily due to the need for a new expansion vessel and associated labour costs. This price reflects the complexity of the repair and the necessity for a qualified technician.