What does the Vaillant ecoTEC pro F57 fault code mean?
The F57 fault code on a Vaillant ecoTEC pro boiler indicates a problem with the external control, which may be due to a communication issue between the boiler and the external thermostat or control device. This fault can prevent the boiler from operating correctly, leading to heating or hot water issues.
Common Causes
- Faulty External Thermostat: The external thermostat may be malfunctioning or incorrectly wired, disrupting communication with the boiler.
- Wiring Issues: Damaged or loose wiring connections between the boiler and the external control can lead to this fault code being triggered.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair the issue, as working with gas appliances and electrical components can be dangerous without proper training.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F57 fault could be around £120 to £180, primarily depending on whether the external thermostat needs replacing or if wiring repairs are required.