Digital Ascaso coffee machine shows E2 and does not produce steam; steam boiler does not heat.

Safety first: Unplug the machine and let it cool fully. Steam boilers can remain hot and pressurized for a long time.

Steps to diagnose E2:

• Reset the machine: Disconnect power for several minutes, then reconnect. If E2 reappears immediately, proceed with inspection.
• Locate the steam boiler NTC: Remove the top or side panel to access the steam boiler. The NTC sensor is usually threaded into the boiler body with two small wires leading to the control board.
• Inspect wiring and connectors: Check for burnt insulation, loose plugs, or corrosion at the sensor and board ends. Clean light oxidation with contact cleaner and reseat connectors.
• Measure sensor resistance: Disconnect the NTC and measure resistance at room temperature. Compare to the brew boiler NTC if identical type. Infinite or near-zero resistance indicates a failed sensor.
• Check harness continuity: If the sensor is within expected range, test each wire from sensor to board for continuity. Repair or replace damaged wires.
• Replace components as needed: Install a new steam boiler NTC if defective. If sensor and wiring are good but E2 persists, replace the main control board.

Note: After replacing the sensor or board, clear the error by power-cycling and allow the boiler to heat while monitoring for leaks or abnormal noises.