Lisa Riordan

Glenn Herbert wrote:The system diameter does not directly relate to the riser height. It is common to make the feed tube height 1 1/2 to 2 times the system size, so 12" to 16" for an 8" system. Using the 1:2:3 or 1:2:4 ratios, this would give 12:24:36, 12:24:48, 16:32:48, or 16:32:64 feed tube to burn tunnel to riser. (Measured along the outside edges of the components.) The burn tunnel can and should be shorter than 32" in most cases. 1:1.5:3 is another ratio I have seen, which would give 16:24:48, quite practical with standard materials. I would not cut the barrel down in any case; the taller the riser is, the better, within reason. Extend the riser to make it 2" below the barrel top.

An 8" J-tube system can ordinarily support up to 50' of horizontal ducting, minus 5' for each 90 degree elbow.

Wow 50 feet so two 90's would knock it down to 40' feet my greenhouse is 24x16.

So extend the riser to 1.5 or 2. Inches below the top of the drum and not cut it down, okay. So would it be okay to use 8" elbows to construct the j tube or firebricks are better?

Ernie Wisner wrote:no problem thats why Erica and I hang around here.
have fun experimenting.
and yes you will want the same cross sectional area throughout the stove. (8 inch all the way)

So if I use 8" tube the heat riser should be 24" tall? If that is correct is the barrel going to be cut 2" taller? Also what is the maximum length I can run the bench before its counter productive?

Thanks,

I have your book just not clear on this issue as this is going in my greenhouse.


Lisa