My 12,000 BTU portable AC experienced this same problem. Remove the outer casing and you will find a drain pan, under the coil, with a PLUGGED drain hole. The drain hole allows condensed water to run over the hot condenser coil for evaporation and then blown out the exhaust port. Mine has a reservoir on the bottom with a dipper to throw water back onto the hot coil. There is also an auto shutoff if the reservoir is full.