Bodum coffee maker with digital display shows E4 and shuts off shortly after starting; steam seems excessive or water spits violently.

Safety first: Unplug the coffee maker and allow it to cool completely. Steam and hot water can cause serious burns.

Steps to try:

• Fill reservoir properly: Ensure the water tank is filled between the MIN and MAX marks. Do not attempt to brew with very low water levels.
• Descale thoroughly: Overheating is often caused by scale restricting water flow. Fill the tank with a 1:1 vinegar and water solution. Start a brew cycle and let it run until you see hot vinegar entering the carafe, then pause for 20–30 minutes. Resume until empty. Follow with 2–3 full tanks of clean water.
• Check outlet and spray head: Remove the filter basket and inspect the shower head or outlet nozzle for coffee oil buildup or mineral deposits. Clean with a soft brush and warm soapy water. Do not use sharp tools that can deform the plastic.
• Ventilation: Make sure the coffee maker has at least a few centimeters of clearance on all sides and is not placed under low cabinets where steam can accumulate and cause overheating.

If E4 persists: The overheat thermostat or control board may be faulty. Because these are safety-critical components, further repair should be done by a qualified technician or by replacing the unit.