Hey fellow permies!
I'm working on an ambitious RMH design for a basement of my Victorian home, and am currently having draft issues. I'm not getting a Rockety burn, just a room full of smoke, and am not sure where my problem is.
Here's a FB album with pics and notes on the project. https://www.facebook.com/media/set/?set=a.10202401067609300.1073741830.1271531391&type=1&l=0f8c4492c8
I have an inline duct-fan installed in the exhaust pipe just before it leaves the basement, I thought it would be useful to get a draft started but... I was hoping I wouldn't have to rely on it.
My main questions are:
1. Should I increase the ascent or angle of the exhaust flue as it leaves the barrel?
2. Does the flue HAVE to grow larger as it leaves the barrel? It's an 8 inch pipe through out the mass, then reduces to 6 inch before going vertical leaving the basement (see pic #9).
3. How much space is needed between the top of the riser and the barrel? It's currently 3 inches. Seems like it might be too tight... but what would be optimal?
NOTE: I have approx. 45 feet of 8 inch pipe to be encased in cob mass. Which is more than most RMH designs I've seen. So I was intending on increasing the riser and barrel length, by adding a 2/3's barrel on top. I'd read that the greater the length of barrel and riser, the more heat generated/fuel consumed. Is this true & recommended given the length and u-shape of my bench?
If you would please look over my project and give me your learned opinions, that would save me a lot of trouble.