I have a goodman air handler. it is some how creating negative preasure when it is buttoned up. it wont let water drain from the pan. all of the water is not going into pan it will some how get sucked to the sode of the unit snd drain from bottom corner of unit . when u take the cover off the air handler the air lock is relaesed and the water runs into drain line of the pan and flowa outsode like it should amy oke got a clue why ? filter is brand new upstairs in return duct .. there is not a filter im the air handler .. there never has been one in there