F11 - Return sensor short circuit

What does F11 mean?

The Vaillant Ecotec Plus Boilers have detected a short circuit in the return temperature sensor (NTC). This indicates an electrical issue with the sensor or its wiring, preventing accurate temperature readings.

• Defective NTC sensor.
• Short circuit in the cable harness.
• Damaged cable or sensor casing.

Click steps to track your progress.

1. 1

   Check the NTC sensor connection to ensure it is secure and properly attached.

2. 2

   Inspect the cable harness for any visible damage, kinks, or loose connections.

3. 3

   If you are comfortable, use a multimeter to check the resistance of the NTC sensor and the continuity of its harness.

4. 4

   If the issue persists, contact a qualified heating engineer for further diagnosis and repair.