DIAGNOSIS This is almost always a dirty or misaligned float switch. The little plastic float inside the bucket well gets stuck in the ‘up’ position, tricking the unit into thinking it’s full.
FIX Unplug the unit, pull out the bucket, and locate the small black plastic float at the back of the well. Manually press it down a few times to make sure it moves freely. While you're in there, wipe out any dust or debris in the well with a dry cloth that could be jamming it.
IF THAT DIDN'T WORK Check that the bucket itself is seated perfectly. If it’s even slightly crooked or not pushed all the way in, it can hold that float up. Also, ensure the unit is on a perfectly level floor; being tilted back can cause this.
HEADS UP This is a super common maintenance issue. Plan to check and clean that float well every couple of months during heavy use to prevent it from happening again.