Display shows E3 and brewing stops shortly after starting on a Klarstein coffee maker with grinder (e.g. Aromatica series).

Safety first: Unplug the machine and allow it to cool completely (at least 45 minutes). Do not bypass any safety devices.

User-level checks:

• Verify water supply: Ensure the water tank is full and properly seated. Never run the machine without water.
• Descale the system: Run a full descaling program to clear mineral deposits that can cause overheating in the flow heater or boiler.

Internal inspection (advanced):

• Remove the bottom or rear cover to access the heating block.
• Locate the thermal fuse and bimetal thermostat mounted on or near the heater.
• Check for signs of burning or discoloration. A blown thermal fuse will usually show no continuity when tested with a multimeter.
• Inspect the water tubing for kinks or blockages, especially silicone hoses leading to and from the pump and heater.

If the thermal fuse has opened, it must be replaced with an identical temperature and current rating part. Investigate and correct the root cause (scale, blocked hoses, failed pump) before replacing. If you are not experienced with mains-voltage repairs, seek professional service.