Display shows E04 and the machine stops; often occurs during or after a steam cycle.

Safety first: Overheating components can cause burns. Turn OFF, unplug, and allow the machine to cool for at least 30 minutes before touching metal parts.

• Check ventilation: Ensure the coffee maker has adequate space around it and that ventilation slots are not blocked by cabinets or walls.
• Descale thoroughly: Run a full descaling cycle with SMEG-approved descaler to restore proper water flow through the boiler/thermoblock and steam circuit.
• Clean steam wand: If your model has a steam wand, purge it after each use and clean the tip with a pin to remove milk residue that can cause backpressure.
• Reset thermal cut-out (if accessible): Some models have a manual-reset thermostat on the boiler. With the cover removed (only if you are qualified), press the small reset button on the thermostat once the unit is cool.
• If E04 recurs frequently: The NTC sensor or thermostat may be faulty, or the boiler is heavily scaled. Professional inspection and possible replacement of the NTC sensor, thermostat, or thermoblock is recommended.