First, thanks for the info from previous questions about ductwork and air flow. I got assurances that if I didn't like the install, they'd make the ductwork right. I told the guys to come on out and they installed the Trane XV95 furnace (60k btu) along with a 2 ton XL16i AC, just left about a half hour ago. Everything seems fine, no excessive noise, and the unit heats and cools well.
The 60K btu XV95 is supposed to have a line out for exhaust and a line in for cumbustion air from the outside. I have two large PVC lines going from the furnace toward an outside wall. Just before they exit through the wall however, they come together in a Y into a larger single piece of PVC, so there's only one large pipe that exits to the exterior. I'm wondering why two separate lines weren't run to the outside? The guys had gone by the time I climbed up, pulled down ceiling tile and checked this out, or I would have asked them.