Here are a couple of shots of the horizontal unit. Cat IV Click to Enlarge 32.58 KB Click to Enlarge 58.36 KB Click to Enlarge 57.1 KB The last two both have the drain line running up hill to clear the pan to get to the drain line. Click to Enlarge 35.04 KB This shot shows the basement condensate line entering the waste stack, there is not trap below the entrance to the stack... Anatol