Lester Hurst

I counted the 5 ft vertical exhaust pipe and the elbow at either end of it, imediately behind the barrel.

Thank you very much for your helpful responses.

Yes I can see the fire brick glowing at the inside beginning of the burn tunnel, I cannot see or photograph the exterior as that is covered with sand /clay mix already. A whiff of the exit gas if very mild smelling and does not burn your nose.

Dimensions are as follows : feed tube floor to top =16". Burn tunnel end to end = 27". Cross section is 9" high by 5.5" wide =49.5 sq in, this is the same thru out the 8 in. system except for the external chimney which is 42 sq in. Heat riser floor to top is 38.5". Top of riser to top of barrel it's about 2.5". Mass tubing is 8" round, with 5 elbows to chimney entrance,of course one final additional turn to begin journey up the chimney, and 25'of straight. External Chimney is 20' high, ending 2' above roof peak.

Learning more all the time, I see 2 issues that may improve performance, I do not have my burn tunnel insulated (just the 2.5" dense fire brick ) cover with mass, and I can increase the height of the heat riser.

Also I would like to add an additional loop of pipe and mass if possible with out hindering performance. This would add 4 more elbows and 20 additional feet of straight pipe. Bringing the total straight pipe to 45' of straight and 9 elbows, plus the 20 ft of external chimney. Thoughts on this ??

Thanks again both Glenn and Allen !
-Lester

Hi to all you interesting folks,

Is there a way to determine if my 8 inch RMH is experiencing the high temp reburn (2000 plus deg F)? Some times it burns rather quietly esp if i have 2 larger pieces of wood in the feed tube -3" to 4" diameter logs. A full tube of smaller pieces burns with more flame and mild torch sound.

I expected to see higher barrel temps, a very vigorous burn, produces only max of 600 deg F on the top of barrel located directly above the heat riser. As it burns down it soon cools to 250 or 300 deg on top of the barrel, other wise it seems to be functioning great. It is not producing smoke from the chimney except for a few minutes when I add more wood. Is that proof of gases reburning or just the result of an efficient burn ?

Heat riser is 29 inches high from the ceiling of burn chamber. Made of 1 1/4 inch thick dense fire brick with 3/4 inch dry perlite packed around outside of brick, contained by 12 inch stove pipe.

Is there a test I can do? To be sure?

Thanks, Lester