I've resently cleaned the gunk out of my AC unit drain pipe and the unit is running just fine again. To get to the clog, I had to cut into the existing PVC pipe and repair it afterwards. The original PVC drain pipe had a shallow trap (not like a U trap on the sink, but much more rounded) between the AC unit exhaust port and the clean out "T". I'm thinking of replacing the drain pipe with newer PVC and I'm wondering why there is a trap there at all. It seems that the flow would be much more efficient without any small dip and incline as it exits the AC unit. Can anyone tell me what purpose this trap serves? It seems to me that it's just another low spot for further gunk to build up and it makes using a snake even harder. Do I need this trap or can I just replace it with a straight section of PVC? Thoughts and comments appreciated. Thanks!