Home Improvement Questions? Ask a Handyman for Answers
Did you remove the packing clip/stop from the float? They use a clip or some other mechanism to keep the float from bouncing around in shipping. It also prevents the float from functioning properly if you don't remove it.
Has the water level dropped significantly after it's done pumping?
Then the pump or float mechanism is faulty. Return it and get another one.
I'm assuming you don't have a hose for a condensate drain and it's not pushed too far into the tank