New AC units don't drain as the old units. They have a splash tray built into the bottom to catch some of the condensate and use it to splash the water over the coils to aid in cooling. If the water level gets too high, there is a drain hole, but it is always located at a higher level to make sure that the spalsh tray gets filled with enough water to aid in cooling. The fan itself is used to spray the water over the coils -- that's why you hear the sounds of water being agitated.