I have just installed a Goodman 115K high efficiency furnace. I have 3" PVC pipes for the air-intake and flue. I followed the rule of a 1/4 inch upwards slope per foot of flue pipe run from the furnace. I also have a Trane Bayvent200B to terminate the 3 inch pipes on the outside wall. Because I would like to mount the bayvent vertically, I will not be able to have a 1/4 inch upward slope for fresh air-intake from the furnace. Does the fresh air-intake need a 1/4 inch upward slope for direct vent installations?

[Edited by nikk on 10-02-2006 at 08:59 PM]