F.11 — Return NTC short circuit

What does F.11 mean?

The boiler has detected a short circuit in the return NTC (Negative Temperature Coefficient) sensor. This indicates a fault with the sensor itself or a short in its wiring, leading to incorrect temperature readings.

• NTC sensor defective.
• Short circuit in the cable harness.
• Cable short-circuiting against the casing.

Click steps to track your progress.

1. 1

   Reset the boiler by pressing the reset button.

2. 2

   Power off the boiler, wait a moment, then power it back on.

3. 3

   If the error persists, contact a qualified service technician to inspect or replace the return NTC sensor and its wiring.