I am no expert ,but I have three thoughts on this looking at your pictures.First you might try taking 2 sections of pipe off near the 180 degree turn.This could improve your draw by shortening the overall length .Also as a general rule the chimney should be 2 feet above anything within 10 feet.If its still possible to shorten your burn tunnel that could help too.
Ok,well to wrap this up,last night I made tabs and bent them over to the barrel (picture 3) and then I crudely insulated the feed tube/burn tunnel area with face brick.I also covered the holes in the base layer of brick that the system sits on.The draw improved slightly but the temperature increase was really good (400 +) with an oven therm.surrounded by brick.This is also with less than seasoned Hickory and Maple.So thanks everyone for the help! I believe that with better insulation around the core area and dryer wood,it will be even better yet.As far as my dimensions and barrel placement are concerned,I think the system will run well as is.This is a work in progress you could say ,and its looking like WE have the bugs mostly worked out now.Thanks again!!!
Byron,i can probably get in and make tabs and get them bent and clear.The riser is wrapped in fire rated insulation with the fire brick being on edge.Then wrapped in galv.sheet metal.The bench area is at this point only covered in busted up concrete block in sizes from sand to golf ball.Everything is deep freeze here and waiting on warmer weather to complete the mass in a less insulating fashion.
Mikael,I believe my measurements are within the 1:1.5:3 suggested dimensions except maybe the riser is a bit short ,but within the specs as far as I have read.Byron ,The j tube is made of full size fire brick with the riser being insulated about 1.5"and wrapped with sheet metal.3" gap at the top of riser.With the barrel being offset to allow for shorter burn tunnel.It then enters 8" galv. HVAC pipe all the way to the top off chimney.There does seem to be some black residue in the cleanout area near the vertical transition.
I am a first time builder and have had my system up and running for a month or better.From the beginning the RMH has had good draw with no smoke back and a good rocket sound.My problem has been barrel temps are low.As far as I can measure with crude oven thermometer,its about 200 degrees ball park,on the top of the barrel.My dimensions are 6x6 feed at 13"deep,6x6 burn tunnel at 15" and 6x8 riser at 32".It is possible for me to close the riser size down with some major fire brick cutting,but if that doesn't sound like my problem I would rather not do all of that extra work.Being that the system has what I consider (good draw) this seems like, in my limited knowledge,the only thing I have wrong.If more information on my system is needed,ask away!Thanks
Erik,in your last paragraph you talked about heat transfer with pebbles being better than sand.That will actually be to my benefit because when I break up the block there will be pieces from pebble to golf ball and larger.I thought that any air space would act as an insulator.This build is in my garage and it only needs to keep the temps hopefully above 40.The block pieces will be contained in a block box which will be about 18" high 15 ft wide and 32" deep.That will allow me to test it with only block fill and see how it goes.Thanks again.
Being that the ground is frozen here,what clay type mix can be bought ? Could I just use sand for the first few feet as filler then go to mortar or will the sand being like an insulator retain the heat to the mortar area?
This has probably been discussed before but my search didn't answer this.I have access to large amounts of broken block for the mass of my first time RMH .My question is what can be used other than cob to fill in the gaps between broken up block? I was wondering if a dry pack sand/portland mix will work or type s or n mortar otherwise.This will only be for the mass area from the 55 gal barrel out.Thanks
Thanks Thomas,That gives me some pictures in my head on where to separate the duct work past the mass and then use a shop vac from two different directions to clean it out.The layout I have planned doesn't work out to well for cleanouts and this will work out much easier.Thanks again!
I have read that it is possible for these systems to not even need a classic style chimney? Just a vent to the outside.I do understand though that a chimney does create draw too.I guess that being said I need to add in a test chimney and try again.
These are my current measurements Feed tube is 6 x 6,burn tunnel is 6 x 6 with a 7.5" ceiling length,riser 6.5 x 8 x 32 top to bottom,2.5" gap from riser to cap. I have the barrel offset and the sheet metal covering my insulation is 4" or more for a length of 19" from the barrel.From the floor to base of barrel is 7" x 16".The 19" and 16" measurements are straight across not with the arch of the barrel.Both of which should be good when compared to the 6"x 6" burn tunnel.The only 2 things that I can see that could be wrong are the riser dimension is a bit big and the fact that it is not hooked into a chimney,possibly limiting the draw that it might get from that.Thoughts?
Thomas/Ramzez,Well I am failing miserably here.Thomas I tried the P channel but didn't really notice any audible or visual difference.That being said,it may just be my design.I will ask now more about the burn tunnel and the distance the flames travel in your systems.My burn tunnel has a 10" long ceiling,with a total of 18" to the back of the riser.When I fired it up yesterday and got a good roar going,the flames are just getting visible at the riser.I'm wondering if this is now my issue?Should the flames be coming high into the riser or at least part way up?I believe my riser is high enough because even when i add height to it the draw stays the same as far as I can see and hear.I believe we have cured the small amount of smoke back in the feed tube by decreasing the measurement there and tightening up the riser As soon as I place the lid over the barrel now,it's almost an immediate shut down.As far as I can tell ,my measurements (2-3" from riser to lid) around the riser (more than 2" all the way around) and 50 square inches at the outlet should be good???
Brett,My start up sounds like yours.I use a propane torch with a long flex hose so it can get down inside.I had it going for about an hour this evening.Starting with some paper and small cedar kindling and slowly progress to larger pieces up to the 1 inch square range.Even after that hour the wood still seems to have to be played with a lot to keep it going even though the draw seems sufficient.So I am hoping with some other fuel that will get a hotter fire going that doesn't need so much attention.Thanks
Ramzez,Thanks for the great replies! I just got back in from reducing the riser size to 6.5 x 8 and also reducing the feed tube to match the burn tunnel size of 6 x 6. I used some concrete block soaps (1.5 x 7.5 x 15.5) in the riser and a fire brick into the feed tube.Only to adjust my measurements for the test.I got a decent fire going and the sound is good and rocket like and seems to be getting more draw.BUT ! The fire never does get very hot.....so I am thinking now that my fuel is holding things back??? At least the smoke back from the feed tube has been stopped.My goal for Saturday is to find some really dry oak for another test run and see if that makes a difference.I will let you know,Thanks again
Thomas,Yes I have the Ianto Evans book and according to what I read on page 32-33 A (feed tube) could be 6 x 8 B(height of feed tube) should be kept short,mine is 10 inches C(burn tunnel) should be the tightest part but no dimension is given,so I went with 6 x 6 and the riser (F) should be 7 x 7 and I am at 8 x 8 The riser can be anywhere from 25 - 50 inches tall ,I am at 32 inches.So as far as I can tell,my only off measurement would be the riser at 8 x 8
Being that my burn tunnel is short,(only 10 inches) its easy to get the draft started and going,but for some reason I still get some smoke coming back through the feed tube.Almost like the draft could be stronger???
Thomas,Thanks for your replies.I have tried closing off the feed tube in small increments and adding to the height without much luck.Could the size of the burn tunnel (6 x 6) compared to the riser (8 x 8 ) be an issue? If my wood isn't VERY dry could that be an issue?I wouldn't say my wood is damp,just not seasoned dry. In my reading I understand that the burn tunnel should be the tightest spot in the system and as short as possible.Would it be worth trying to close either the tunnel or riser down to a smaller size?
Picture was taken before mortar and is now squared up on corners of riser and the feed tube was made larger than is shown.It was 6 x 6 and is now 6 x 8. The lid is just sitting on top for my own reference.
I am using full size fire brick on my first attempt to build a RMH. I am not sure if my J-tube measurements need to be adjusted. My measurements are: 8x6 feed tube; 6x6 burn tunnel that is 10 inches in length; 8x8 heat riser; 10" rise at feed tube and 32" rise in heat riser (from bottom to top on both). I don't seem to be getting enough draw and I am getting some smoke back out of the feed tube. This is without the barrel over the heat riser. I have tried adding eight more inches of rise on the heat riser but that does not seem to help. As far as I have read, these measurements should be close. Any advise would be greatly appreciated. Thanks, Mike
First time poster.Building my first RMH to heat my garage.I am using full size fire brick for my J tube and want to insulate the heat riser.My question is,with 1.5 inches of insulation around the riser,would sheet metal be sufficient as a wrap to contain the insulation.Do I need to worry about sheet metal melting or .I was thinking about using roofing metal that is 29 gauge or something similar.As a last resort a 16 x16 clay flue liner is an option but quite spendy.Any thoughts would be helpful.