Display shows E05; machine stops mid-brew or will not start; often associated with steam functions not working correctly.

Safety: Unplug the machine and allow all steam components to cool completely before opening the housing.

• Reset and test: Disconnect power for 5 minutes, then reconnect and try only a coffee brew (no steam). If E05 appears even without steam use, proceed.
• Access steam circuit: Remove top/rear cover to locate the steam block or steam section of the thermoblock. Identify the steam NTC sensor and thermostat (small disc or inline thermal device).
• Inspect wiring: Check connectors to the steam NTC and thermostat for looseness or corrosion. Reseat all connectors.
• Test thermostat: With a multimeter, check continuity across the steam thermostat at room temperature. An open circuit indicates a failed thermostat that must be replaced.
• Test NTC sensor: Disconnect the NTC leads and measure resistance. Compare to the coffee thermoblock NTC if identical type; a reading of 0 Ω (short) or infinite (open) indicates failure.
• Replace faulty components: Install a new steam thermostat or NTC sensor as required, using thermal paste if specified by Zwilling. Ensure proper mounting to the metal surface.
• If sensors and thermostat are good: The main control board may misread steam temperature and should be evaluated or replaced by a technician.