Question: I put a Fisher wood burning stove in my basement recently. It has an eight inch stove collar out the top. I have connected the rest as follows: two feet of eight inch pipe straight up, an elbow, approximately six feet of pipe running upward at an angle of 15 degrees, another elbow, a reducer collar down to six inches, and five feet of insulated stove pipe. This sets off the brick house about four feet and does not go above the roof line but does get a strong horizontal wind most of the time. I put a shanty cap on the top of the flue for down drafts. The problem is cold air coming down the pipe causing smoke in the basement. This doesn't happen all the time. I also get black water dripping through one of the seams inside the house. When this gets hot it boils and expands to a black crust which clogs the flue. I have to clean the flue about every three weeks. I have tried burning the wood faster so the moisture would be carried out of the flue before condensing. How do I stop the smoke problem? It has recently smoked the day after cleaning the flue once the fire burnt down. Answer: The entire installation is wrong. A chimney height of at least 15 feet is needed for good updraft. In addition, the pipe should not have been reduced from 8 to 6. This is a 50% reduction in chimney capacity. Also, too many elbos...which reduce the draft even more. In summary, you are operating a distillery, not a stove. Wood is at least 25% water, so the water is condensing before it gets out the chimney.