[jcg31]

Thanks folk, I went with constricting the flue a bit. For now I just lined the 12"x8" with some Kaowool and that had an immediate and positive impact. What I will do next weekend is either install a pipe within the current system, or cut down the existing 12x8x24 flue and install an 8x8x24 in its place. Either way it will be fairly easy and cheap to fix. Thanks again for the direction!

Jim