I need to run a flexible chimney liner down 2 stories and into my basement to vent a 6" nat gas furnace exaust and a 3" nat gas water heater exaust. I'm thinking I need to run a 6" liner, but I don't want the gas from the 3" water heater to cool too much on it's way out the roof. What say you? Which size do I buy? via /r/DIY https://ift.tt/2N3p9Lh
