My Traeger GBU-70 Pellet Furnace finally broke to the point I can't repair it, at least for now. (Control Board timer blew), so I have picked up an Englander 25 PDVC stove to use at least as a stop-gap for now. The layout of the house does not offer an option to install on an exterior wall, at least without making some very drastic changes to the furniture / electronics layout. (House has in wall wired surround sound an built-in for TV that would end up being 3 to 4 foot off center if I placed the stove in the corner to allow for a through wall install). So, with that in mind, I have an interior wall that I will be installing the stove on. For purely aesthetic reasons (I would like to build a mantle above the surround), I am wanting to offset the vent pipe by about 4 feet, before turning to vertical, and going through the roof. My questions are as follows: Is it OK to use 3" pipe for the 3ft Horizontal run? (I believe the recommended EVL for 3" was 15, so I wasn't sure how that would work out since I am going to have a mix of pipe sizes) I would like to be able to come out of the stove with 3" pipe, then transition to 4" at the tee before going vertical. This is just simply because I already have a 3" Appliance Adapter, 3" 90 elbow, and the 3"x3ft section of pipe, which would save me roughly $100-$150 on material. If my research here is correct, I would have the following EVL: 3" Elbow = 5 EVL 3" x 3ft Pipe (Horizontal) = 3 EVL 3" to 4" Tee = 5 EVL 10ft 4" Pipe (Vertical) = 5 EVL 4" Vertical Cap = 0 EVL Total 18 EVL Should I slope the Horizontal run downward slightly into the tee? I was thinking having a slight downslope into the tee would help direct any ash into the cleanout. Is it "OK" to use the 90 degree elbow when exiting the stove? It seems the preferred method is to use a tee in lieu of an elbow, but if the elbow will work, that is quite a bit of cost savings there ... but I don't want to sacrifice safety or performance to save a few bucks. Thanks in advance for any help or tips.