Rheem classic 90 plus venting question

jjconst07

Hello, I have a rheem 90 plus furnace, it is vented through the side of the house with the standard pvc piping, my question is this:

I am putting a 3 season porch on the back of the house where the furnace vents, the vent comes out just a few inches below where the bottom of the new roof trusses are, since the original pvc is running horizontal for about 20 feet before it finally comes out of the side of the house, can I run it a few feet more at the same horizontal plain, then put a 90 degree turn in it and then simply run it straight up through the roof ( which will be about 40 inches or so ) and then I can just build a small soffit inside the porch to conceal the pipe? If the answer is yes, I often see where the pipe that exits through the roof on houses then gets a 180 pipe on it so the opening faces the roof again I am assuming so that rain and snow doesnt enter the pipe, would I want to do that as well ?
The furnace is a Rheem classic 90 plus 120,000 btu.

Thank You
Joe

redline

How many elbows are currently on the vent pipe?

(it sounds like you will reach the limit on the vent)

jjconst07

I am guessing 4 elbows so far, its all in finished areas now, but when I built the house I remember about where it went, and to do that would take 4.