Since you have ceiling controls, you do NOT have a Freeze Sensor. If the water only comes inside when you shut it off, then, as another mentioned, you have ice build up and when it defrosts when turned off, the ice that hangs over the side of the drain pan comes inside. To prevent Icing on manual control AC units, run on HI/COOL. Also, since Hubby installed, I would think he may have not installed correctly. There is a insulated barrier between the Intake(air filter) and the cold exhaust. IF that barrier is not installed correctly or even NOT installed, the unit will freeze up. Doug