I have an existing masonry chimney set up with a free standing wood stove with 8" vent stack entering an 8" hole in masonry. Wood stove pipe comes vertical out of stove, 45s, and enters masonry. The pipe runs the length the horizontal hole in the masonry and ends where it meets the flue. Hope that makes sense. I am installing a free standing pellet stove in the same location (Breckwell P4000 vermont cast) and have questions about the venting pipe. My plan was to run the pipe very similar to what is described above. T outlet on stove, vertical pipe for roughly 4', 45, horizontal run into flue with 4" to 8" thimble. My question is is this correct? I did not think I needed to run the steel vent pipe the full length of the chimney and out the top in this type of set up but I cannot find anything anywhere that confirms this. I thought you only needed to line the chimney when you have a fireplace opening, not a wood stove 8" hole setup. Any advice would be greatly appreciated. I have learned a lot on this forum in the last couple of months prior to getting my stove. Just signed on to get specific help getting set up. BTW, chimney is an external masonry with a debri cap on the top.