Display shows E1 and the coffee maker does not start brewing.

Safety first: Unplug the coffee maker before inspecting internal parts. Allow the unit to cool completely.

Step-by-step:

• Check water tank: Remove the Tristar water reservoir, fill it to at least the MIN level, and reseat it firmly. Many Tristar models use a magnet/float and reed switch in the base; if the tank is not fully seated, the sensor will not detect water.
• Inspect float: Look inside the reservoir for a small plastic float. Make sure it moves freely and is not stuck by scale or debris. Rinse and clean with warm water and mild dish soap, then test again.
• Clean sensor area: On the base where the tank sits, wipe the contact area and any small plastic tower or window where the sensor is located. Mineral buildup can interfere with the sensor.
• Reset power: Plug the unit back in, power it on, and see if the E1 clears. Try removing and reseating the tank a few times.
• Internal check (advanced): If comfortable and out of warranty, unplug the unit, remove the bottom cover, and locate the water level sensor wiring harness leading from the tank area to the main control PCB. Check for loose connectors or damaged wires. Reseat the connector on the PCB.

When to stop: If E1 persists after cleaning and reseating the tank and you find no obvious wiring issue, the level sensor or main control PCB is likely defective and should be replaced by a qualified technician.