DIAGNOSIS The water level sensor inside the reservoir cavity is either blocked or malfunctioning. Debris or a stuck float is the most common culprit.
FIX
- Unplug the machine and remove the water reservoir.
- Look inside the cavity where the reservoir sits. You'll see a small white plastic float.
- Use a clean, dry cloth to wipe the float and the surrounding walls clean of any mineral scale or coffee grounds.
- Manually move the float up and down a few times to ensure it's not stuck.
- Replace the reservoir, plug the machine back in, and the error should clear.
IF THAT DIDN'T WORK The sensor itself may have failed. Try a hard reset: unplug the machine for 5 full minutes, then plug it back in. If the 'add water' light persists with a full, clean reservoir, the unit likely needs service.
HEADS UP This sensor is very sensitive to scale. If you have hard water, descale the entire machine (not just the reservoir) more frequently to prevent a repeat.