Display shows E1 and the unit will not start or stops shortly after starting.

Safety first: Unplug the unit before removing any covers.

• 1. Power reset: Unplug for 10 minutes, then plug back in and try again. If E1 returns immediately, proceed.
• 2. Locate room sensor: On many De'Longhi portables, the room NTC is behind the front grille near the air intake. Remove the front filter and look for a small probe or sensor clipped near the intake.
• 3. Check wiring: Ensure the sensor is firmly plugged into its connector and that the wires are not pinched or broken. Reseat the connector on both the sensor and the main PCB if accessible.
• 4. Test sensor (advanced): Using a multimeter, measure the resistance of the NTC at room temperature and compare to the service manual chart. A reading of near 0 Ω (short) or infinite (open) indicates a bad sensor.
• 5. Replace if faulty: If the sensor is defective, replace it with a De'Longhi-compatible room temperature sensor. Route the wires as originally installed and secure the sensor in the same location.

If a known-good sensor still gives E1, the main control board may have a failed sensor input and should be replaced by a technician.