Outside Air to Combustion Fan Question

I have read alot about you guys bringing outside air directly to your combustion fan with PVC and or hose to the outside. I know the fan itself is 2.5 inches in diameter and some guys on here have used 2.5 inch tees and 2.25 pipe to the outside.

My problem is I can't find 2.25"or 2.5" PVC at my local hardware stores, only 2" and then 3". Nothing in between. Can I go with 2" pipe or will that be too restrictive? I am installing this to my stove in my living area so I want to conceal this as best as possible.

Any insight would be appreciated.

I just have my 4" combustion air duct duct taped to the end of my combustion fan. Some outside air may spill in the area but that's ok. There is air coming into your home regardless and by having this combustion air duct, I am controllong where it enters.

I used 4" drain-type PVC (thinner wall than plumbing PVC, and cheaper, too!) from Home Depot to build my combustion air intake. As I had a long run of about 18 feet or so, I figured the larger diameter pipe would be less 'resistance' to the air flow. Yes, the intake on my Alaska Channing III is 2.5" or something like that, but I'd rather supply it too much air than too little. I think the stove runs with a bigger flame on a setting than without the piped in air, so I presume it's burning hotter. And, as mentioned in another thread here, that's less cold air being sucked into the house through the doors, windows, cracks, and everywhere else.

Well I finally cut the hole in the side of my house for the pipe. I went with the 2 inch due to my family room and not wanting a huge pipe in plain view.

So far, I have a 90 on the outside with some window screen mesh for now to keep away the critters. Then about 3 feet of PVC to the inside where I have another 90 to take the pipe down to the floor. Thats as far as I got right now. Cold air is definitely coming through the pipe.

I will keep you guys updated on my progress.