Diagnosis
This is often a protection delay. The compressor has a built-in timer that prevents it from restarting for about 3 minutes after it shuts off, to protect it from damage. If you’re cycling power quickly, you’ll hear the fan but not the compressor.
How to Fix It
Unplug the unit from the wall. Wait a full 5 minutes—set a timer. This gives all the internal electronics and the compressor protector time to fully reset. Plug it back in, turn it on, and set your desired humidity level. Now, just listen. You should hear the fan, and after a minute or two, a distinct ‘click’ followed by a deeper hum—that’s the compressor engaging. Leave it be and see if it starts pulling water.
If That Didn't Work
If after the reset there’s still no compressor hum, and the room is definitely humid/warm enough, the start capacitor for the compressor might have failed. This is a common wear part. You’ll need a technician to test and replace it; it’s a relatively inexpensive fix if you’re handy, but requires working with high-voltage components.
Heads Up
Never plug the unit into a power strip or a heavily loaded outlet. It needs a dedicated wall outlet for the consistent, strong current the compressor requires to start up.