Error F01; the water temperature reading is clearly wrong (e.g., shows very high or very low when the water is lukewarm).

Safety: Turn off power and allow pipes to cool before touching them.

• 1. Locate DHW NTC: On Ferroli water heaters, the DHW sensor is usually clipped to the hot outlet pipe or integrated into a sensor pocket.
• 2. Check mounting: Ensure the sensor is firmly attached and that any thermal paste or clip is intact.
• 3. Inspect cable: Look for cuts, kinks, or signs of overheating. Reseat the connector on the PCB.
• 4. Replace sensor: If the sensor is physically damaged or readings are unstable, replace it with the correct Ferroli DHW NTC.