Diagnosis
The internal condensate drain system is blocked, or the unit is not level, causing water to spill from the internal pan.
How to Fix It
First, ensure the unit is perfectly level. Use a small bubble level on top. Adjust the casters or add shims under them. Water must flow to the tank or drain hose, not slosh out.
If That Didn't Work
The drain hole or internal tube is clogged with algae or debris. Unplug the unit. Locate the drain plug/port on the back or bottom. Use a pipe cleaner or soft wire to gently clear it, then flush with a cup of warm water.
Heads Up
If you're using the continuous drain hose, make sure it's downhill from the unit with no kinks or loops that create a clog. A hose lying flat can cause water to back up and leak internally.