Masonary Clay Flue Sizing

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Joined: Mon. Jul. 21, 2008 2:38 pm

Post Fri. Aug. 15, 2008 10:10 pm

I have a square clay flue liner that is 11 x 11 inch Inside dimensions. Did not measure OD but think it is 12 x 12.
Want to run a Leisure Line hearth Model 6 inch flu thru the fireplace damper and into this flue. Have read that to get proper draft the ratio of the flue's effective draft area , approx 100 inches for my flue, should not be more than 3 times greater than the 28 inch area of the 6 inch stove outlet. Does this apply to the LL Hearth model or just wood stoves?
My math comes up with a ratio of 3.5.
Is this a problem that requires a flue liner? Does a taller chimney increase or reduce the draft? My chimney about 30 ft high.
Does a barometric damper help increase or control the draft?
Can I install an adapter to increase the LL Hearth collar to 8 inches or would that really screw up the stove?

I really do not want to install a stainless steel liner and hope this does not bust the plan of installing the LL Hearth .

Any help appreciated.

Jerry & Karen
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Joined: Mon. Jan. 23, 2006 7:30 pm
Location: Berwick, pa

Post Sun. Aug. 17, 2008 7:05 pm

Before I would spend any more money, I would first try the stove. A coal stoker does not operate off of draft like a wood fire or hand fired coal. A stoker stove is a forced draft therefore pushing the gases out. Don't get me wrong, you still need a draft but try it first. If all else fails, you can install a draft inducer to move the exhaust. Cost is much less then a SS chimney.

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Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea
Location: Guilford, Connecticut

Post Mon. Aug. 18, 2008 1:47 pm

You don't need anything if the chimney isn't falling apart, you have a 30' clay tile lined chimney, it doesn't get any better than that. A baro is designed to limit the total draft to a set point by allowing room air to replace air that normally would be drawn through the firebox and overfire your appliance, typically around -.06".
Nothing is impossible for people who don't have to do it themselves.

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