Same issue still continuing. I bought some kiln dried wood to test my wet wood theory and have been burning for almost two hours now. I still end up needing to push it into the horizontal part past the feed tube to prevent smoke back. I finally installed my probe thermometer on the barrel and although it's not measuring the hottest temps which are in the center it is still staying between 900-1000 degrees since it got up to temp.
If anyone has any insight or any idea what else could be the problem please I really want to fix this
So I tried splitting some of the wood even smaller and stacking it pretty tight together like you mentioned. It worked as the fire was in the front of the bundle (front being towards the heat riser) but as soon as it spread towards the middle it started burning up again and pretty serious too. So I tried to think this over and here are the possible reasons I can come up with:
I need to do more of a primer fire to get the temp in the heat riser up to create more of a draft
My wood is too wet and not seasoned enough to burn hot enough to create a good draft
At the bottom of my chimney on the outside of my house there is a clean out but the door is broken and all I have over it is a rough piece of slate
My burn tunnel is too long (doubt it but still) I have 4 half barrels on an 8" system
My COB is still too wet and is sucking up too much heat to prevent getting a good draft at the exhaust, along with any of the above.
This could also be a combination of any of these issues but this is just what I came up with so far. Any ideas or comments would be greatly appreciated.
Still getting succesful burns overall but I am still having some slight problems with the fire going up the wood and eventually leading to some smoke going into the house. Much better then before but still something I'd like to eliminate. I am able to control it though by pushing some of the pieces down into the horizontal part of the unit. I know my wood is not dry enough because I can hear the moisture sizzle off some of the pieces, plus my mass is still very much wet, but is there anything else I can do to prevent this?
Success!!! I got everything going and burning properly. Still not as much of a roar as I have seen on other successful RMH's but none the less. It took a bit to get going but once it did I had no smoke back and all the wood burned sideways like it should have. I only had a short fire, about an hour and a half, because it started doing too good of a job and got the house a little too warm. It looks like the main issue really was just getting a proper seal on everything to get a good draft going through the system. The interesting thing though is that my exhaust temps didn't go above 90 and I still had success.
Sorry my wife said I had to finish my son's new room first before I could keep working on the RMH. His room is done now so today I plan to make the extra cob I need to fill everywhere that's smoking and then I'll try again with a quick newspaper only fire and see how it goes. Hopefully I won't have any other smoke leaks in the system. I'll try to post some pictures this weekend but I'll do that in a new thread
Did some more trouble shooting and got the barrel cap to fit better. Did a small test fire with just newspaper and found out that I must have shifted the barrel around too much while trying to seat the barrel cap so the cob around the barrel moved and I'm getting a bit of smoke from there. Also the cap on my ducting for my clean out apparently isn't holding a tight deal cause I am getting smoke from there as well and I have no way of accessing that until the cob dries because I put up a temporary wall to keep the cob flush with the front. Gonna trying jamming some cob over that and picking it away later. Hopefully this fixes my draw issues
Thanks for the insight. I didn't know that about the fan creating a stronger chimney. As for contacting dragon heaters I did after I posted here as I found a major problem. The gasket between the barrel and the barrel cap that they sell is not working and is letting smoke out. I didn't notice this during the hotter burning because it was able to perform the secondary combustion so it must have been nearly clear but as I was letting it die out o boy did I notice the smoke start to billow out from between the barrel and the barrel cap. So I called right away and honestly did not receive the greatest customer service claiming that I needed to cut the width of the gasket before installing it. I'm sorry but I was already put of slightly by receiving a product with absolutely zero instructions but now I am told that I had to trim the gasket? Why sell a product of it isn't even the correct width for its use? I will be calling again tomorrow when everyone else is in at the company and asking to speak to someone in charge because this is very disappointing so far.
I tried out the fan idea today. It worked pretty good for the first 15 minutes but then the fire started spreading up the wood while still burning sideways at the bottom and thus cause it to start smoking again. Am I doing something wrong? I can't keep letting my house get filled with smoke every day. By the way my entire system did heat up, I could feel it on the clean out cap at the far end, and my exhaust was around 90-100 degrees. Also I am using a dragon heater 8" core with their heat riser and I added 2-4" of clay slip/perlite around the core but not the heat riser for extra insulation. My transition has a CSA of around 120 sq in and I am using half barrels for my ducting, just thought I'd add some more background info.
So I'm done laying all the cob down for my first rocket mass heater but I have a pretty big problem. Two days ago I had the cover over my nice dry seasoned wood break off and had it get rained on all night long. I tried burning to start drying out the cob but it all started smoking back badly. The only way I was able to stop the smoke is to place a cinder block over the opening and let the secondary air intake do all the work. This worked but not to well the fire burned kind of slow and I only got a low rumble not the big roar the rocket should give. I am going to be building a new storage area for my wood next spring but obviously this doesn't help me now. Is there anything I can do to still make this wood work? I was thinking about supplementing with some wood pellets but not sure if that would help.
So my RMH build is finally underway but no matter how much I look at it I just really don't like the way the steel drum looks. I wanted a way to cover it but I know it still needs to give off heat. So my idea is to push cement board a few inches away from the drum and then tile the cement board. I think that this should be enough to prevent any high heat from reaching the cement board and damaging it. What do you think?
I'm going to post this on the Cob section as well because I need a quick answer. I am getting ready to start cobbing my bench for my rocket mass heater. I found a source of clay dirt and made sure it had a decent level of clay by doing the usual quick test of wetting it rolling it into a snake and bending it into a circle which worked with no breaks or cracks so I am assuming I have a decent amount of clay in the dirt. I made a few test bricks to determine the correct ration of clay to sand using 1:1, 1:1.5, and 1:2 for dirt to sand. I've let them sit to dry inside my house for the last 3 days and then today I tested them by dropping them from about 4 feet onto concrete. The problem is that they all broke into at least 3-4 pieces. The 1:1.5 seems to do better then the other two but this still isn't the most encouraging sign. Is this ok with how it broke given how I tested it or is this no good for making the bench? Please any quick feedback would be greatly appreciated since I really need to start construction soon with how cold it is getting outside.
Hi everyone. So I've gotten majority of my questions answered now and even found a source of clay dirt or I get to build my RMH with cob now and not concrete. There is still one thing that I realized I don't have full clarity on and that's the clean outs. I know where to put them, I know how to tie them in. What I don't know is how to cap them off so none of the gases from inside get out into my living room. Also since these are metal would the cap get hot to the point that it could burn someone if they touch it?
So I'm just about ready to start building my new system. Just a quick over view before the questions. I live in northern New Jersey my home is approx. 1200 sqft with an open concept and I plan to have my rocket mass heater as my only source of heat for the winter. I am using an 8 inch system that I am going to get from Dragon Heaters. I am going to cover the unit with a perlite/clay slip mix about 8" underneath and about 8-12" around. The is all going to be incased with cinder blocks to form the outer walls. Instead of using a standard barrel for the bell I am going to be using 24" x 24" chimney flue liners, I am going to be lining it with Inswool Ceramic Fiber Blanket and using Rigidizer to harden the material and increase its life expectance. This should keep the temperature fluctuations down and prevent cracking of the chimney flue liners. I am going to be topping it with a slab of soapstone (unless someone has a better, or cheaper, idea). I am then going to be using 55 gallon drums as half barrels in my bench to use as my very large second bell. I am able to fit 9 half barrels total with the size of bench I am building with a total of 2 90 degree turns. At the end of the system I will be using 8" piping to connect to my existing 18' tall chimney. The entire system is going to be lifted up off the floor by placing brick in rows going from front to back with 2' x 2' pavers placed on top that I will be sealing together with mortar to make it air tight. There will also be a 4" gap around the entire system to allow for air flow. I live on a boulder with no clay soil or any immediate access to clay soil so instead of COB I am going to be using concrete for my mass. I am also going to be running a water line through my mass that will be used for an aquaponics systems that will be on the other side of the wall. The plan is to circulate water from the fish tanks through the line to keep the water temperature up during winter. At one end of the system I am going to have a chaise lounger that will have a half barrel underneath but not as part of the system. It will be used to store wood and will hopefully help dry it out a little extra from the heat of the mass. I am then going to cover the front of the system and the clay flue liners with stacked stone to improve the aesthetics of the system and will be using futon mattresses for cushioning. The back rest will be wood boards that will have a cavity inside (I am going to make the backrest thick) that will be covered with a water proof liner and used to house some indoor plants in a wicking bed system.
Ok so that's the system. Now the questions:
From the half barrels to the exterior of the system how thick should the mass be, both for the top and front?
Will there be enough length of travel for the heated air before exiting the system? I know this is something that I have to actually trial but just wondering if there was a quick answer like "it should be ok" or "that's not nearly enough"
Would the water line end of syphoning off too much heat taking away from the main living space?
Do I have a thick enough layer of perlite between the system and the outer concrete walls?
I am planning to have a 2" gap between the heat riser and the soapstone top is this ok or should I increase it?
Should I add more insulation to the heat riser to reduce the space between the heat riser and the inside wall (of the clay flue liner with the ceramic blanket)?
Should I make the soapstone removeable to service the unit?
Any other comments about the system are VERY welcome.
I am planning to start building mid October so I still have some time to make adjustments.
From what I read it is recommended to keep an air space between the mass and any walls or floor. For the walls this is simply done by just not building right up to the walls. But how do I achieve this for the floor?
I am still a little unclear on the clean outs. I know I need one right at the start of the horizontal run but where else should I put them and what's the best way to make them?
I was also wondering about the manifold (barrel to ducting). I am a very visual learner and I have read about this area and how it should look but I am still a little unclear. If anyone could either provide me with a diagram, picture, or just a better discription on this area that would be a great help.
Thanks for the help Al. Just some more background. I am located in Northern New Jersey and I live in a Ranch style house that I have turned into an open concept house to help spead the heat of the wood burning stove. Th RMH would go in my living room where we already spend most of our time so it would never be left unattended while running. I'm attaching a rough design on what I would like it to look like. The outer boarder is a basic idea of how the living room is shaped and I the ducting ends at my chimeny. As for the chimeny itself, it is in good running order and I have in cleaned and inspected yearly since I heat my house totally off of the wood burning stove. I will go through all the information that you have pointed me in to try to get better informed on the RMH. I'm not building anything until the end of May at the earliest so that leaves me quite a bit of time to fine tune my plans.
I am currently planning a build for this spring/summer of a TMH. After the polar vortex we are done with waking up every 2 hours to add wood to the wood burning stove and still wake up in the morning with frozen pipes. I have read the book and done some research but I figured asking the questions directly would make things simpler.
My plan is to get an 8” Dragon Burner core to save a lot of the guess work on getting it all setup just right. Also the wife has demanded that this look nice so using a metal barrel is out of the question since from what I read covering it with cob would lower some of the efficiency (please correct me if I am wrong on this). So my idea is to build it out of firebrick instead as my understanding is that firebrick absorbs heat fairly quickly so it should still keep enough of a difference in temperature to keep things running smoothly. Would this work?
My next question is to the location of the “barrel”. I’ve been seeing them placed off center of the heat riser and I read that you want to keep the temp lower on one side and higher on the other but I’m not sure why or what this actually does.
With the spacing between the “barrel” and the heat riser according to the book it should be 2-3” for an 8” system but more would be fine. What is the advantage/disadvantage of adding the extra headspace? Also my understanding is that you want the CSA of the heat riser to be the same as the CSA of the inside wall of the “barrel” to the outer wall of the heat riser (insulation) is this correct?
I am planning on building this system in my living room and I want to retain as much of the heat as possible, would a perlite/clay slip mix along the exterior wall and the floor the full length of the bench help with keeping the heat inside my house?
As for the bench itself, the book mentions using rock or some other material that can quickly absorb the heat from the exhaust tunnel then using cob the rest of the way but I have also read that you should use uniform material throughout the bench for best results. Which is it?
I am also planning on running the bench approximately 35-40’ but I have room to run it longer if I should. I have heard however that a 90° bend if the same as running the system 5 extra feet. Is this true and if so would a wide turn improve this instead of a sharper bend? Also, could I run it longer than that, besides the fact that it really won’t be providing much heat anymore is there any other negative?
Finally (for now) I have read that you need a vertical exhaust at the end of the system. If I run long enough of an exhaust tunnel that the temp is very low would I be able to just have a vent that goes out through my house similar to a clothes dryer or do I NEED the vertical exhaust? If I do need it can I use the chimney I currently have for my wood burning stove?