No, not "above", just upwind. They are all about the same height.
Water heater is an AO Smith powervent. I don't have the manual for the
(Luxaire, don't have the model number on me right now) furnace - I'm
going to try and get ahold of it though.

Your saying the intake is above the exhaust for the furnace and water
heater?

If so, what is the make, model of the furnace?

And what type of water heater do you have that requires a 6" PVC
pipe?

~kjpro~