My house has a main chimney primarily used for the first floor fireplace. This big old fireplace was originally used for cooking when the house was built. This chimney is the old, non-lined, wide-open type and it has a stove pipe that accesses it on the second floor. The chimney has a large flag stone on the top to keep rain out. The second floor stove pipe just sticks out a few inches into the chimney. I have a woodstove connected to that second floor pipe. My concern is that this woodstove is exhausing into a large chimney and this creates a lot of creosote. I have read that having woodstove smoke output into a large chimney can cause creosote buildup since the smoke hits the walls of the relatively cold chimney and leaves a lot of creosote. When I stand in the fireplace and shine a flashlight up the chimney I can see shiny creosote on the walls of the chimney starting just above the stove pipe. I'm leery of a chimney fire.....
I'm thinking to make the setup safer I might: 1) put in two stainless pipes in the chimney and 2) put in a woodstove in the fireplace instead of using it as a fireplace. In this way, I would have metal all the way to the roof with two separate pipes for each source of smoke. The only somewhat tough part is what to do with the second floor stove access. I'm thinking that I could put in a pipe for that stove, but run it all the way down to the first floor and just access it with a "T" on the second floor where the stove exhaust would access the pipe. In this way, I could clean this pipe more easily from the first floor. Otherwise, it would be almost impossible to clean the pipe since it would have a 90 degree elbow where it entered on the second floor. I'd appreciate any comments from those who have tried putting pipes in a large chimney and how this has worked for them.
Rob NE PA