Digital Ascaso coffee machine displays E1 and will not start heating or brewing.

Safety first: Unplug the machine and allow it to cool completely before opening any panels. Hot boilers and live wiring can cause burns or electric shock.

Steps to check and address E1:

• Power-cycle the machine: Unplug for 5 minutes, then reconnect and power on. If E1 clears temporarily and returns, the sensor or wiring is likely faulty.
• Access the brew boiler area: Remove the top cover (usually a few screws) to expose the brew boiler and its NTC temperature probe (typically a small brass or stainless sensor threaded into the boiler with two wires).
• Inspect the NTC probe wiring: Look for broken, pinched, or heat-damaged wires and loose spade or plug connectors. Reseat any loose connectors firmly.
• Test the NTC sensor: With the machine unplugged, disconnect the sensor from the harness and measure resistance with a multimeter. A typical Ascaso NTC will show several kilo-ohms at room temperature. An infinite reading indicates an open sensor; near 0 Ω indicates a shorted sensor.
• Check continuity to the control board: If the sensor tests OK, test continuity of each wire from the sensor connector to the main control board connector. Repair or replace any damaged wires or terminals.
• Replace faulty parts: If the NTC is open/shorted, replace the brew boiler NTC probe. If wiring and sensor are good but E1 persists, the main control board temperature input circuit is likely defective and the board should be replaced.

When to call a technician: If you are not comfortable using a multimeter or removing the top cover, or if the control board appears faulty, contact an authorized Ascaso service center.