Hello, We have been using a old US Stove co. Forester we installed in the 80's. It had a 8" flue going into a triple wall chimney. At the time the triple way was the great thing. Well we use it for about 2 years and just started using it again 4 yrs ago. The creosote build up was very heavy I was cleaning the chimney every 2 weeks never could get the chimney hot enough to keep the creosote down. So last year I thought I would try to "fix" the problem, I packed the the inter wall of the chimney with Rock Wool. It did help keep the flue warm and still the outside was cool. We are going to change the stove this year to a new EPA Certified one. It has a 6" flue. What I need help with is if my way will work and be safe. I removed the Rock Wool so now it's back to a air cooled chimney. I want to run a 6" pipe up inside the 8" and keep it centered with using 3 screws sticking out of the 6" about every 2 feet. Then going to fill the void around the pipe with Vermiculite as it is fire proof and a good insulation. It would still be keeping cool as the 2 outer layers will still move air. Is there anything wrong with going this way? I was thinking of using 24ga steel pipe for the liner but if needed would go for stainless. Thanks for the help!
Don
Don