Display shows E12; machine may not heat water or may shut down shortly after starting.

Safety: Unplug the machine. Work on the heating circuit only if you are trained; it carries mains voltage.

• Check for obvious damage: Remove the side panel and visually inspect the thermoblock and wiring for burn marks, melted insulation, or disconnected spade terminals.
• Reset thermal cut-out (if resettable type): Some models have a manual-reset thermostat on the thermoblock. If present, press the small button to reset. Do this only when the machine is cold.
• Descale: Heavy scale can cause overheating and blown fuses. If the heater is still functional, run a descaling cycle after any repair.

Most E12 cases require component-level electrical repair (heater, fuse, or power board). This should be done by a qualified technician.