rst
New Member
Posts: 24
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Post by rst on Apr 7, 2014 17:23:22 GMT -8
I've been contemplating an 8" RMH. I'm imagining an L-shaped bench that has the barrel/J-tube/etc near one end with 8" tubing going out from below the barrel, turning 90 degrees, then 180 degrees at the other end, then 90 degrees up into the vertical stack at the corner of the L. The chimney would then exit through the wall at 90 degrees, turn up 90 degrees and then end above the roof line (very windy here). Basically, I'm looking at about 20 feet in the bench plus 4x 90 degree turns, then a 15-20ft high chimney with two 90 degree turns on it. drawingMy question is, are there any potential efficiency issues or otherwise with such a configuration? I had read that 20 feet was a minimum for bench length if one wanted to have the chimney be relatively cool. Would I be wasting a lot of heat to not have a longer bench, or do the 90 degree bends significantly impact what a reasonable length is? Would the chimney pipe have the potential to get notably hot in such a system? Thank you for your time.
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Post by satamax on Apr 7, 2014 20:31:00 GMT -8
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ekw
New Member
Posts: 14
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Post by ekw on May 1, 2014 12:38:03 GMT -8
Sounds pretty workable to me, too. You will be a little shorter than some of the 8" systems, but similar to the one we use in our own house*. Our exhaust temps are about 115 to 150 F (depending if we're burning just a few hours every other day in shoulder season, or longer burns 4-6 hrs in a cold snap). We detailed our chimney just like a woodstove chimney (HT) from the through-ceiling thru the roof, and so far have added enough insulated pipe above the roof to get up about 3-4 feet above the roof, but not quite fully above the ridge of the house. If you're going out a wall I would definitely budget for enough insulated pipe to get up well above the roof eaves, even if you have to add it bit by bit. -Erica W *( Our Cabin 8" plans document our heater, and I've put up a few photos and diagrams on the online store for preview. Or contact me if you want to see our L-shaped 8" plans, coming out soon.
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rst
New Member
Posts: 24
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Post by rst on May 3, 2014 19:09:54 GMT -8
Thanks for the info on temperatures. We detailed our chimney just like a woodstove chimney (HT) from the through-ceiling thru the roof, and so far have added enough insulated pipe above the roof to get up about 3-4 feet above the roof, but not quite fully above the ridge of the house. If you're going out a wall I would definitely budget for enough insulated pipe to get up well above the roof eaves, even if you have to add it bit by bit Do you recommend actual Class A outdoor chimney, or is the cheaper double-wall pipe sufficient (I am not subject to code/inspector approval)? I assume the insulated pipe is going to be necessary outside to maintain a good draw? Thank you
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