My a/c unit in the attic has a main drain pipe and then what I think is an emergency overflow pipe. The emergency is just an inch long and would dump water into the pan underneath, whereas the main drain goes to my sewer. About 6 inches from the a/c unit, the main drain has a T in it, with the leg pointing up. Both the leg of the T and the emergency pipe have a pretty strong flow of cold air coming out of them when the A/C is running. On the one hand, this doesn't seem right, but on the other, if I capped them, then the emergency would be worthless and I'd probably blow the sewer trap dry on the main line. Any thoughts on if this is the right or wrong setup?