Oddly enough I just noticed that the CSA of a RMH in inches is roughly equal to the run in feet. Likely pure coincidence, but I'm a geek for numbers
Well a 12 inch system will go about 100 feet a ten inch about 75 feet and 8 inch about 50 and a six inch about 45 maximum.
Remember that absolute maximums.
After my crazy numbers observation, all but the 6" in Ernie's recommendations fit my hypothesis. I still think a 6" system should be more like 35ft max.
Alan Wright wrote:We've got 50' with an 8 inch system. We use an in-line fan to get it going and then once its warm she runs good, except when the wind blows hard. I know its "cheating" but we love the in-line fan, takes all the difficulty out of it.
While having an inline fan obviously helps with draw, if anybody decides to use one it shouldn't simply be put directly inline of the exhaust unless it's being run all the time. When it's not running it will slow/restrict the exhaust flow. There is scant discussion of an inline fan's proper placement as it's regular use is not generally recommended.
It's possible that you could eliminate the need for a fan by having a higher vertical chimney, and/or using a different chimney cap/top