Flame creep up on outdoor mockup

[josephcrawley]

I've set up an 8 inch test system outside to see how things go. The stove burns great with no barrel. With the barrel it always starts to creep up the wood until it reverses the draft. I have restricted the throat of the stove to no effect. The test system has about 10 feet of 8" pipe with a 3" vertical piece at the end. The riser and feed can are as close to each other as possible(about 6" long). The flame reverses even with the intake restricted with the 5 gallon can lid on it. my heat riser is 3' and is insulated with some fiber glass(temporary)

I have not been real anal about selaing cracks since I am just testing although I have sealed the big ones. Also I have been burning pine sticks which are supposed to have creep problems. My fear is that if pine will back draft then so will anything else and fill my house with smoke.

I've been thinking of getting rid of the downdraft feed in favor of a side feed like the donkey did. It seems like this would have a very hard time reverse drafting.

thanks

[swizzlenutz]

You should try it with the wood you intend to burn and see if that cures the problem. To me it actually sounds like the barrel maybe just a little to close to the top of the riser and you're slowly choking it out. Pine and other pitchy woods will always creep out because the resins are consumed quicker then the wood beneath the bark. You could also try pieces of pine with no bark on them to see if that might be it. Ah hell...I dunno what I'm talking about half the time so wait until you hear from Donkey before doing anything drastic. He's one of the local experts on this board. Swizzle

[hpmer]

I think the Swizzman is right. Donkey often suggests getting the stove running and then slowly lowering the barrel down to get to the right level (which is known by the sound of the roar). If the thing works great without the barrel, there should be some inflexion point that will get you the best performance with the most heat. And, the way I've read the book, it seems the only reason to have the space above the riser optimized is if you want to heat a pan on top of the barrel. If your only interest is stored heat, then more room up top would insure no restrictions.

Did I get that about right, Donkey?

[Donkey]

Got it.
Sounds like Swizz and hpmer have this one nailed.
My guess would be barrel gap, or some restriction downflow somewhere.
What they said.