Display shows E2 and brewing stops shortly after starting.

Safety first: Unplug the coffee maker and let it cool for at least 30 minutes before opening any panels.

• Descale the unit: Heavy scale on the Tristar aluminum heating block can cause abnormal temperature readings. Run a full descaling cycle using a manufacturer-approved descaler or a 1:1 white vinegar and water solution. Then run 2–3 full tanks of clean water to rinse.
• Check ventilation: Ensure the coffee maker is not pushed against a wall or under a low cabinet that traps heat. Overheating can trigger E2.
• Inspect thermistor connection (advanced): Remove the bottom or rear cover (model dependent). Locate the heating block and the small NTC thermistor clipped or screwed to it with two thin wires leading to the control PCB. Check that the thermistor is firmly attached to the block and that the connector on the PCB is fully seated.
• Look for damage: If the thermistor wires are burnt, brittle, or broken, the sensor must be replaced. Do not bypass the sensor; it is a safety device.

Note: If E2 returns immediately after power-up and wiring is intact, the thermistor or control PCB is likely faulty and should be replaced by a professional.