If you drain your dishwaser into a garbage disposal and you have a loop in the line from drain pump to mimick a trap -how can it back into the sump?
Answer HI Dan. You wiouldnt think so but pull the drain hose off the sink connecter and place it in a bucket. Now insert a straight screwdriver into the sink connecter and feel if the plumbing knock out plug is still inside. If so remove it. Make sure the drain loop is mounted as far up under the sink behind the basin so the drain hose is now taught on a down slope into the sink drain. Remove the bottom kick panel. Remove the drain hose from the drain pump. At the pump output there is a black rubber check valve that may be ripped or missing part # 8268375. Thank You.