My clean out dripping, why?

We shoot the gun inside middle of the chimney - bad
we shoot by the side -not bad
Or we put the regular thermometer inside for a few minutes - best

I think I need to describe my all my problems clearly so you could diagnose my RMH:

1) From the beginning, I had exactly same problem as in the link Satamax gave: Which is at the begining my RMH burn at the tips of the wood and very nicely. But after burn for a while, my feed tube was so crazy hot that the minute I drop the firewood in, it ignited either full length or very long part of the wood (I had to wear helmet when came near the feedtube so it won't babecue my face). When I saw the link from Satamax it had my exactly problem, I thought after I cool down the top layer of the feed tube just like they did, I should be fine. But after I stripped off the insulation on second layer of feed tube, even my feedtube is not crazy hot and I had better temperature, but still have red charcoals and some burn up

2) I then changed my feed tube 2nd time: used half size bricks at bottom layer and full size bricks at second layer. Satamax and Glen advised bone dried small hardwood at first then big wood and Shilo advised more length to the chimney with cap. I already borrowed the ladder to claim up the roof and bought the cap (please take a look at the photo to see if it is ok). I don’t have any one to help get up on the roof yet. Hopefully next week.

3) Today temperature is 90 degree, but I would want to test about the wood may give red charcoal and I would want to see if changed the size of the bricks on the layer of feed tube would help my RMH. So, I burn 3 loads of small finger sized woods: First and last load with hardwood purchased from hardware stores, and middle load the same wood pick on the street and I used them previous burn. Here is what I find out:
• First load with purchased hardwood: Burn was reasonable at the tips, after burn for a while, I don’t see crazy hot feedtube ignites big part of wood as it did before, neither burn up - good
• The second load (same wood used before): it burned up, burned quick, and turned in to a whole ton of red charcoals.
• The third load, I went back to the type of wood as the first load, burn was nicely at tips: no more burn up and not much red charcoal
• After 45 minutes burns, my feedtube was reasonable hot, not crazy hot, I measured and I had only 525 degree

Here is my what I think:
• So, beside my feed tube was too hot, the wet wood or the type of wood is another reason I have burn up and red charcoal. When winter comes, I think this problem fix itself as my wood have more time to dry off
• I burned three loads, about 45 minutes, but the temperature is only 525 degree. What happen? I should be above 630. Last time after the first fix of cool down the feedtube, I burned 45 minutes and my gun gave me 630 and then after that “OH” which mean temperature was higher than 630 degree. This time it’s only 525 which is worry me a lot. What happen? Please help, 525 is not that nice

• I already insulated the 2nd and 3rd clean out, but the 3rd clean out still dripping. After stop burning for one hour, I opened the 2nd clean out, and there was water inside, little, not much to drip outside but inside there was water.
Question: If my thermal mass doesn’t have enough clay, what kind of problem it causes my RMH . I saw Paul Wheaton used only sand for his RMH. So, if sands alone is ok, then not enough clay should be ok too, right?

If your thermal mass doesn’t have enough clay it will be weak.

RMH with a long mass is very sensitive to high ambient temp like 90F.
did you give it a try (when the mass is dry!) in a winter day?

Shilo
I did this RMH couple months ago, in April, and I think I didn't burn it before did thermal mass. I finished everything then burned. But I think I will redo the thermal mass so I can have some heat stored. As I said before, even when the lid of the barrel go up to above 630, my thermal mass is not hot/warm at all. I checked it many time interval of 2 hours, didn't see any thing. I will do it this week, and add high to the chimney then someday when temperature is reasonable, will try to burn again to see if anything changes, will see.

1) I already redid my cob bench. Doesn’t matter how good/bad is my stove, any heat it can generate should be caught in the bench. So, I redid the cob bench. Last time 5 sands with 1 clay. This time 3 sands with 1 clay.

2) At the time redid the cob bench I took some photos. And before take down the cob bench, I measure some temperature at the 2nd clean out. 1 hour after stopped burning, I opened the 2nd clean out to measure temperature inside, and this is what I saw: On the left side temperature tip the scale of my thermometer, which mean it is higher than 120 deg. But after the uturn, temperature drop to 94 deg. The left side was hot, and after the uturn temperature was cool. I think the hot air turned into water at the cap, because my cap expose to the room which is cooler temperature. I took photos ad enclosed. I think I will cut the long neck of clean out #2 (take out the pipe connector which elongate the 2nd clean out). I will put roxul to cover the clean out.

3) I enclosed other photos to show that my new cob bench crack a lot, why? Last time my bench had no crack at all. Now, I just did it on Sunday, and today it already cracked a lot

4) And I added more high to my chimney.

the uturn is o.k.
the cracks is because too much clay for that thickness. you need to add gravel or straw.
the chimney must be insulated.
we can't to find the real problem with no proper delta temp measurements.

Janet. Do you have your wood burning on top of a grate? If not, try one. Just enough to lift the wood and charcoal above floor level and allow the air to circulate underneath and create a hotter burn. I also sometimes open the front of the tunnel a tiny bit to allow a bit of air to have an unrestricted flow directly to the burn tunnel although this means that you have to compensate by closing down the feed tube by approximately the same amount otherwise it will allow the wood to start burning up the tube.

what are all this little chimneys? try to block them air tight.

I never had a chance to burn my RMH since the chimney up higher. Temperature in this area has been always at high 80s-90s. There were a couple of days when temperature at low 80 but I missed them because I was busy remodel my greenhouse. I am done remodel the greenhouse and will pay closed attention to weather, will burn when temperature is at low 80 at least.

My cob bench was totally dried and yesterday I added more cob to fixed the cracks and the tilted/wobbling. The new cob also cracked, but thin cracks only. It should take only a few days to dry off the new cob. After that, when I burn there should be no dripping because the cob are all dried. If there is still dripping then something is wrong

Gusmus, I will try to burn to see if my RMH get better with higer chimney. Then I will make a grate.

Shilo, what do you mean little chimney? which one?


Enclosed is photos of my new set-up greenhouse. I took away the growing tubes and replace by verticle barrels. The growing tubes can grow 14 spots, with these new barrels, I can grow 100 spots. Also, I added an IBC totes 275 gal. Now I have 2 ponds to heat. My goodness, my RMH better be good or I'll be in bigger trouble.

the 1 foot grey chimneys on the grey roof

No, they are not chimney. They are ventalations for bathrooms. They are for the house. The green house is the one with plastic roof, grey roof is the house.

Hello everyone

I just burned my RMH this morning. We fixed only one problem, the other two problem is still there

Here are my RMH problem before:
1) Building up of red charcoal 2) Condense of water in the flue 3) Not that hot

I did a few changes in this burn:
1)add some hi for the chimney
2) redo the thermal mass with more clay
3) Add 1 more layer on the feed tube so it will be high enough to contain the firewood inside so I can closed the feedtube with a brick
4) Cover 2/3 of the feedtube with a brick during this burn
5) Put cob inside the cap of the clean out to make sure clean out cab will not get cold
6) Put roxul to cover all around the clean out
7) I don't have peter channel, neither the crate at bottom

Here is what I found out in this burn
1) Today after for about one and a half hour, I noticed I don't have building up of red charcoal. I think some how add more hi to the chimney and cover the feedtube with a brick help this problem. Right from the begining everyone told me to cover the feedtube with a brick, I couldn't follow because my feedtube is only one layer of brick above the burn chamber, too low to contain the firewood inside to cover with brick

2) During the burn, I noticed their are drips on the bench came from the upright flue. Water condense a lot as the photos
After the burn, I open the 2 clean out, and found out a lot of water condense too. I remember I redid the thermal on father's day, so June 21. It is one and a half month already, should be dried already right. I saw the surface dried off too. Why do I still have condense in the flue?

3) The temperature is not hi, around 550. Why?

Please advise

Additional photos

First photo is the dripping down the the thermal mass
The second photo is the dripping from the 3 clean out, the bottom of the upright flue
The third photo is the wet cap of the second clean out. The cap I already line with cob to make sure it will be warm and not to be cold

Jannet, your mass and chimney are cold. Dripping is normal. That's condensation from moisture in the wood, moisture in the air, and also from combustion, since hydrogen in the hydrocarbons combines with O² you will always have some untill your mass is hot.

Insulating the chimney can help too.

The main reason that my RMH didn't perform right was because of leaking. I had leaks every where. At the 1st clean out, at 2nd clean out, at the 3rd clean out, but leaking the most is at the 2 elbows above the 2nd barrel.

Each elbow has three rings so we can turn. At each ring are thin slots (so we can turn). If you turn the elbow and then look there are slot by the turn around the ring. At my test burn, it smelled funny a little but not much because I always had all the doors opened due to hot temperature of summer day. I think my RMH draw cool air from the greenhouse into the flue which was hot, temperatures different gave lot of condense ... result is my RMH is not hot, weak, didn't burn complete and build up red charcoals. In my case, I insulated the chimney (2 elblows) with Roxul which didn't help much with the leaks that's why I still had problem (Satamax, maybe other people insulate with lay mixed with that's why it seal the leaks ).

I had to buy refractory cement to seal off all the leaks and my RMH is now ok, burn to completeness remain very little or no ashes at all.

With all the fixes before this seal, even it didn't build up that much red charcoal, but I still had a lot of ashes, it wasn't that hot and still had problem with a lot of water dripping out. Now everything is good. I can't measure the temperature because it went over 630 then my heat gun stop reading, but it's very hot and no ashes, burn completely.

I came back to let you guys know so in future if you see someone with the dripping problem, tell the learners to check of leaking and insulate the leaks with something which seal the leak completely

Thank you all and have good days.

Hi Dave and welcome to Permies!
There are a few things that I see that are contributing to your moisture problem.
The  first thing is that burning wood produces a lot of moisture and if allowed to cool enough, it will condense  forming the water you are seeing.
 All of that exposed pipe is where this is happening.  As soon as you cover it up with mass, your problem should go mostly away.  Question: is the vertical stack on the roof insulated or single walled?
If you are not yet prepared to fill your bench with mass, then perhaps you could temporarily cover it with some batt insulation or dry sand to help keep your exhaust temperatures higher and prevent the condensation from forming.
Another source of all that moisture is also coming from your RMH being newly built.  In other words it’s all drying out and that moisture needs to go somewhere.
This is a good learning lesson so please don’t give up!