How to fix Vaillant ecoTEC pro fault code F61

What does the Vaillant ecoTEC pro F61 fault code mean?

The F61 fault code on the Vaillant ecoTEC pro indicates a system lockout due to a fault in the heating system. This typically occurs when the boiler detects an issue that prevents it from operating safely or efficiently.

Common Causes

  • Low Water Pressure: Insufficient water pressure in the system can trigger a lockout to prevent damage.
  • Faulty Sensors: Malfunctioning temperature or pressure sensors may send incorrect readings, causing the boiler to shut down.

Can I fix it myself? (DIY)

If you are comfortable, check the water pressure gauge and ensure it is within the recommended range (usually between 1-1.5 bar). If the pressure is low, you can top it up using the filling loop. However, for any electrical or gas-related issues, it is crucial to call a Gas Safe Engineer.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for addressing the F61 fault could range from £150 to £300, depending on whether the issue is simply low pressure or if it involves replacing faulty sensors, which can be more expensive due to parts and labour.