I have an Englander 25-pdvc that I got used from my nephew. I installed it just recently. I ran the vent through the outside wall to a clean out "T" and then straight up. I wanted to run it high enough to go just above the roof line to keep any blackening of my siding from happening. As I said it goes straight out the wall and then up about 8'. Is this too much rise? Can you have too much rise? Just wondering about this to avoid any future issues. Thanks.