A couple of questions on venting of condensing furnaces (Trane XV95 in particular):
1) Where there is a PVC flue pipe brought through the roof, how far above the roof does it need to extend, and should it have a rain cap of some sort?
2) In my new horizontal attic installation, there's a turbine ("whirllybird") roof vent literally right next to the end of the furnace with the air intake, so there's plenty of fresh combustion air without penetrating the roof. The installer, however, didn't extend the combustion air intake to/through the end (top if it were vertical) of the cabinet. Is this normal/acceptable practice, or should the intake be stubbed outside the cabinet?