I recently acquired a pel-pro pp130 for my apartment to cut some heating costs this winter and am getting ready to install my exhaust venting. My issue is there is an existing 8" single wall chimney that was used for a previous wood stove and the chimney extends about 8 foot past the roof. I have been able to find an 8" to 3" reducer to connect to the existing pipe that is there but my question is will I have issues with this set up as the pel pro manual says to use either 4" or 3" pipe. I really don't want to reline the chimney as it is an apartment and the cost of the pellet stove approved relining kits is quite pricy ($700+) and as I mentioned earlier the chimney extends 8' past the roof line. If worse came to worse could I reline the chimney by dropping in the duralock pellet stove pipe?