Display shows U15 and brewing does not start or stops immediately.

Safety first: Unplug the coffee maker before inspection.

• Reseat the tank: Remove and reinstall the water tank firmly. Push down until you feel it click or fully seat. Some Panasonic models require a firm push to engage the tank detection switch.
• Inspect tank underside: Check for a small plastic protrusion or magnet that actuates the tank sensor. If it is broken, cracked, or missing, the machine will not detect the tank.
• Check for obstructions: Look in the tank bay for foreign objects, coffee grounds, or scale that might prevent the tank from sitting low enough to trigger the switch. Clean with a damp cloth.
• Test the switch (advanced): With the unit unplugged, gently press the small lever or button in the tank bay that the tank normally presses. You should feel a distinct click. If it feels mushy or does not click, the microswitch may be faulty and should be replaced by a technician.
• Try another tank (if available): If you have access to a compatible Panasonic water tank, test with that to determine if the issue is with the tank or the base.