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rocket mass heaters

RMH for Dummies! Please help guide me through my first build!

thomas rubino

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posted 6 years ago

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Hi Staci:
First off , have you looked in one of your ash cleanouts ? I hope they are nearly empty but its worth a look. Also pop the lid on your barrel and inspect the riser.
#1) Food grade Diamatetious earth! Completely human( I even mix a dab in my coffee )and pet safe. Messy in the kitchen like flour but it will help get rid the ant/flea/bedbug/ baby flies... quite a few creepy crawly thing problems. We still get them (90 year old log cabin) but not nearly like we did before D.E.
#2) I think you are still having less than premium wood issues , green still? wet ? This spring commence your wood gathering , wood splitting and building a covered wood shed... Keep a check on craigs list under free stuff or firewood. People give away piles of split dry wood when they suddenly install a different heating system.... but you must be a Johnny on the spot to get it.

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
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Staci Kopcha

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posted 6 years ago

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Hi Thomas,
I will give the DE a go for the ants.

As far as wood, I got the moisture meter. Average reading is in the 20%'s or less. (I tested dry pallet wood as a control, and this tested in the 10's or below). (multiple reads, multiple pallets, multiple pieces.)
If I get a higher reading, I shelve it for next year.
Wood is stored in a nice dry shed with metal roof. Flooring is above the ground (2 +feet) so there is no moisture from below either.

I will try to take pictures today of examples of burn, if that will help. I already got the thing running this morning, so won't be able to check cleanouts/tower until tomorrow, but will do.
I am obsessed with wood! Over x-mas, even had the family picking up deadfall (oak!!) at a local park. We live near a water pipeline, lined with trees. I have scored some wood there (water company has to trim the trail and they sometimes toss the trimmings off to the side. I found a downed (wild) cherry, that I am going to claim as my own. Found 2 leads on Craigslist today.
Thanks!

Eric Hammond

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Hey Staci. I was having trouble with my super flat oak wood scraps from the church furniture place wanting to burn up the sticks. I think there is a boundary layer effect and they make a good chimney without irregularities like naturally found would does. I have found If I block off the feed tube about 1/3, the flames come close to the top but not usually out, I cant say never, but less then 3 times a week. I think closing the intake air off forces it to pull the air through the spaces between the wood and doesn't let them become chimneys. Have you tried this? Also does cracking a window help? If my dryer is going sometimes I need to crack the window so it burns correct.

Staci Kopcha

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Location: Western Washington State

posted 6 years ago

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Eric Hammond wrote:Hey Staci. I was having trouble with my super flat oak wood scraps from the church furniture place wanting to burn up the sticks. I think there is a boundary layer effect and they make a good chimney without irregularities like naturally found would does. I have found If I block off the feed tube about 1/3, the flames come close to the top but not usually out, I cant say never, but less then 3 times a week. I think closing the intake air off forces it to pull the air through the spaces between the wood and doesn't let them become chimneys. Have you tried this? Also does cracking a window help? If my dryer is going sometimes I need to crack the window so it burns correct.

Hey Eric,
Thanks for the info and nice to know someone else had a similar experience. I will try to cover the feed partially and also cracking the window.
LOL- I was thinking of your church pew haul today. We had a big windstorm, which has yielded MUCHO fall of huge evergreen branches. Today I dumpster dived into some "yard waste" bins, and got a nice haul of thick branches. Later, I went for a run on the water pipeline trail near my house and eyed branches downed EVERYwhere. Like a kid in a candy store!! My kids tell me, "Mom, all you care about is wood". (before it was RMH). :)

Gerry Parent

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Staci Kopcha wrote:Hi,
2)Wood woes. While my little RMH is doing great and burning well, I am still unable to burn un-round pieces without smoking. The flames creep up the piece all the way to the top and then it creates smoke. I have tried cutting them shorter, thinner; turning them which way and that, making wide space between them, butting them up to the burn tunnel...nothing. Even the pallet wood does this (not round).
Draw seems strong, but I guess not strong enough. Sometimes I will shove a brick over the top to block the flames. However, any way about it results in smoky air and constant babysitting. (round pieces are pretty much self feeding and I only have to add more).
I am currently going through my wood supply at a fairly good clip. Small rounds are nearing depletion. I have many larger rounds remaining, but they will need splitting (too wide to fit in my feed door), hence the concern.
Thanks!
Staci

Hi Staci, Just brainstorming a few simple modifications that may help to increase the draw and reduce the smoke back issue. (If you havn't already done so)
1) Make sure your cleanout caps are insulated - with rock wool or clay stabilized perlite. This will help keep as much heat in the pipes and add to the secondary draw that occurs in the vertical chimney
2) From what I remember, your vertical chimney is next to your barrel. If you could help channel a little more heat from the barrel to it would also help with the draw. If its silver, paint it black. Two fins wrapped with tin foil could also be used to help reflect/direct the heat there too.

I can't help get this image of you dumpster diving out of my head.... your a real trooper! ;)

Silence is Golden
For all your RMH needs:
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Staci Kopcha

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Location: Western Washington State

posted 6 years ago

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Cooling Dragon...?
Past few days, I have noticed that the bench is not warming much. Right now, after almost 2 hours of solid feeding (my usual mix of wood, nothing different): area around the fuel feed is cool (95- it is usually VERY warm), manifold is cool to touch (87F), bench direct from manifold is 90, rest of bench cool (74). No NEW cob recently and all "newish" cob is dry.
Exhaust is running slightly warmer (100).
Barrel is getting plenty hot, and it is primarily the only heat. The only other thing generating warmth is the cob on the barrel. ( It is dry now and less than 1/3 the barrel. )
Room is not staying warm any more (due to no mass warmth). :(
Weather patterns here have changed since Friday, in that the days have been warmer than usual (50's+), sunny, dry, and frosty nights. Rains are do again mid-week.
I am sitting in my heater now, chilly.

Staci

Satamax Antone

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posted 6 years ago

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Stacy, i would bet on a change of draft.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

thomas rubino

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posted 6 years ago

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Good Morning Staci;

CHECK FOR EXCESSIVE ASH!
Your fire is burning normally, your barrel is hot, and your mass is not.... Check for excessive ash in your pipes! Ash is an insulator, its posable that your heat is rolling right thru and out the stack and not stopping to heat your cob.

If that is the case , try to find a way to blow that ash out rather than trying to use a vacume cleaner. Fly ash will EAT your vacume quickly and ruin it.
Be prepaired if you blow it out.... it will make quite the mess outdoors..

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Staci Kopcha

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Location: Western Washington State

posted 6 years ago

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HI,
Cracked open the barrel and also the manifold and the 180 cleanouts.
Not sure what is considered to be too much ash.
Tried to get pics- but not very good. Manifold, when I reach my hand/fingers in, is only a light dusting. Doesn't seem to be a pile.
Tubes show a thin line of ash at the bottom. Less than 1/2 inch wide and not deep.

(order of photos: 180, 180, manifold, tower, around barrel)

DSC_1360.JPG

DSC_1361.JPG

DSC_1362.JPG

DSC_1365.JPG

DSC_1363.JPG

thomas rubino

rocket scientist

Posts: 6382

Location: latitude 47 N.W. montana zone 6A

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posted 6 years ago

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Well Stacie; You have no ash problem. Believe me you will know when its a problem.

This confuses things some. You did have a weather system change, its possible the draft has gotten so strong its pulling the heat out before it can sink into your mass.
If we find nothing maybe it will improve with the return of the rains(gota love the coast...)

Do you have a ir temp gun ? Can you get top of chimney temps ?

I recently learned about the difference in the temp inside the pipe (gas stream) or pipe surface temperature. Big difference. See my post about optimum stack temps. Maybe you might sacrifice an analog candy thermometer and see what your gas temp is at head high after the mass.

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Gerry Parent

Rocket Scientist

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posted 6 years ago

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Satamax Antone wrote:Stacy, i would bet on a change of draft.

Hi Satamax....could you explain what you mean please? Similar to what Thomas said?

Silence is Golden
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Staci Kopcha

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Location: Western Washington State

posted 6 years ago

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Gerry Parent wrote:

Satamax Antone wrote:Stacy, i would bet on a change of draft.

Hi Satamax....could you explain what you mean please? Similar to what Thomas said?

Hi,
I am wondering about the weather/pressure systems and how/why that is a factor. But that seems to be the only variable here. Amazing that such a thing can be a strong influence on draft and the workings of my little heater. Not my area of expertice (obviously). I am interested in understanding so that I can know how to manage the heater during such a time.
I lit it this morning for a bit. I played with blocking the fuel feed and then trying to block/stuff the burn tunnel. ALso, maybe a good time to put in my fattest pieces of wood.
I only ran it briefly this morning (< 2 hours), so not quite long enough to get a good feel. I will try it again this evening and see if anything helps.
(I remember that this happened previously, if you re-read awhile back in the feed. Suddenly happened and then just the same was resolved).
Thomas, I do have an IR temp, not sure if I will make it onto the roof today, but will try. You lost me a bit on the pipes and candy thermometer.

Thanks!
Staci

thomas rubino

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posted 6 years ago

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Hi Staci; Simple and easy. An analog candy thermometer that goes over 300F, is inserted into your stove pipe about head high, before it leaves the house. This will read the true exhaust gas temperature.
On my new rmh it has surprised me how much hotter that gas is than the stove pipe.
I paid $7 delivered from ebay. Yard sale , junk store , dollar store... even less.

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Staci Kopcha

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Location: Western Washington State

posted 6 years ago

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And then: Hear Ye Hear Ye: (I would assume that this includes RMH???)

Stage 2 Burn Ban Called for Greater Pierce County 2, effective 12 pm today, January 14, 2019.

Use of fireplaces and wood stoves is prohibited until air quality improves.

Overnight, air pollution levels exceeded UNHEALTHY FOR SENSITIVE GROUPS for several hours. We expect current conditions (light winds, clear skies, and colder temperatures) to continue through late Tuesday.

See our press release for more information.
http://bit.ly/2RLtYuI

Eric Hammond

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Location: SW Missouri

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Honestly Staci, by building a rmh you have made a concious decision to improve outdoor air quality by providing a super efficient burn. I would disregard that message and assume it did not apply to me.

Satamax Antone

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Gerry Parent wrote:

Satamax Antone wrote:Stacy, i would bet on a change of draft.

Hi Satamax....could you explain what you mean please? Similar to what Thomas said?

Yes; extremely cold, and drafting like mad. Gases have no time to exchange heat.

There is another one i didn't think of.

Mass has been discharged of most of the heat, due to scarce fires when the weather is mild, and takes forever to charge back to normal.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

thomas rubino

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Location: latitude 47 N.W. montana zone 6A

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Hi Staci;
I really like Max's thought about warm days and your mass cooling off. I think this is what you have happening.

Your portion of the coast has no real extreme cold like the French alps do.

Oh and I agree with Eric, that air quality thing is for your neighbors blaze king stove … stuffed full of wood and shut down so it smolder's for the next 12 hrs. (those type should be heavily fined) Unfortunately Pierce county would be glad to bust you if even one neighbor reported the steam coming from your chimney. (light it in the dark :) )

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Satamax Antone

gardener

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Location: Southern alps, on the French side of the french /italian border 5000ft elevation

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thomas rubino wrote:Hi Staci;
I really like Max's thought about warm days and your mass cooling off. I think this is what you have happening.

Your portion of the coast has no real extreme cold like the French alps do.

Soo far, we've had two days of real cold. There's barely any snow left on my land.

But, since this is southern alps. We get very mild weather some days. It already happened to ma lately. We've had two or three days without freezing, then down to minus 17 at night. But i start to have proper experience heating my place with a rocket.

Some nights, i open the windows, to charge the mass more. Provisioning for a colder following night or next day.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

Mark Brunnr

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The no burning alerts more apply to standard heaters, where a layer of smoky haze can be seen a mile away. If you have a bush or tree near your RMH exhaust the steam might dissipate before it’s visible at all. If this is your only source of heat legally, then there might be an exception as well. But if this was built in the gray area of permits then best to run it after the sun sets just to be safe!

The holy trinity of wholesomeness: Fred Rogers - be kind to others; Steve Irwin - be kind to animals; Bob Ross - be kind to yourself

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Graham Chiu

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Maybe there needs to be some standardised method of calculating the efficiency of a rocket mass heater. You know how much wood you're using so the approximate amount of energy release, the mass of the heater, the ambient temperature, the temperature delta of the heater, and the flue temperatures. So, one should be able to sort out where the issue is?

Mark Brunnr

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You'd also need to measure air flow too to determine total heat loss right? Not sure if a meter inserted in the exhaust flow would cause issues with draft under normal use or not. But weighing the wood when brought in to sit next to the barrel and dry a bit, then weigh again to see how much moisture loss occurred and/or moisture metering, calculating BTUs based on wood species and weight... sure seems like a lot of work! Maybe checking with a match need the feed, put it out and see how strongly the wisp of smoke is pulled in to see if you might have too much draft? Or choke the feed a bit with a brick, to reduce the CSA at that point to balance the draw?

What kind of chimney cap is installed outside? If it's just a T or an elbow aimed down to keep rain out, then perhaps adding a couple more Ts would help to reduce the possible pressure change due to wind gusts? I'm not sure if that would help or not but one of the RMH books I have mentions this I think.

The holy trinity of wholesomeness: Fred Rogers - be kind to others; Steve Irwin - be kind to animals; Bob Ross - be kind to yourself

Staci Kopcha

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Location: Western Washington State

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Satamax Antone wrote:

Gerry Parent wrote:

Satamax Antone wrote:

Mass has been discharged of most of the heat, due to scarce fires when the weather is mild, and takes forever to charge back to normal.

I run it every day, very consistently. There has not been a time for it to cool off.
SO I am guessing it is weather /pressure system.
How to you circumvent that??

Staci Kopcha

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posted 6 years ago

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Graham Chiu wrote:Maybe there needs to be some standardised method of calculating the efficiency of a rocket mass heater. You know how much wood you're using so the approximate amount of energy release, the mass of the heater, the ambient temperature, the temperature delta of the heater, and the flue temperatures. So, one should be able to sort out where the issue is?

Hi Graham- that would be most helpful!

Staci Kopcha

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Mark Tudor wrote:

What kind of chimney cap is installed outside? If it's just a T or an elbow aimed down to keep rain out, then perhaps adding a couple more Ts would help to reduce the possible pressure change due to wind gusts? I'm not sure if that would help or not but one of the RMH books I have mentions this I think.

Hi Mark,
It is just a basic "Class A" triple insulated 3ft chimney coming straight (vertical) out an almost zero pitch roof. Basic Duravent chimney cap, with rain guard.
Not sure of adding T's...? maybe for a horizontal chimney outlet. I maybe missing something.
S.

Staci Kopcha

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I am burning covertly tonight.(Shhhh) Burn ban to be lifted tomorrow afternoon...?
Yesterday, the mass heated like "normal", today not heating again.
Weather has been consistent.
Longest period of NOT firing the heater has been about 12-15 hours, in the past few months.

Graham Chiu

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Hi Staci

If you have an IR thermometer I think it would be useful to record the temperatures along the path of your stove. The more data you have the easier it will be to deduce what's happening.

Satamax Antone

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Staci Kopcha wrote:I am burning covertly tonight.(Shhhh) Burn ban to be lifted tomorrow afternoon...?
Yesterday, the mass heated like "normal", today not heating again.
Weather has been consistent.
Longest period of NOT firing the heater has been about 12-15 hours, in the past few months.

Stacy, i think it's just your feeling of "not heating like normal"With my batch, it takes about four hours, when stone cold, for the outer skin, to raise of 1C° That's 20cm thick bricks, with a metal inner skin of 2mm and a tiny air gap.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

thomas rubino

rocket scientist

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Hi Staci; ??? works well one day and not the next ??? that's crazy.... No weather changes at all ??? Well this is a fine kettle of fish you have gotten into Ollie !

Ha Ha been visiting a Washington state green store lately ? No seriously though I can't understand how it can be that erratic. Start a log book. Take IR readings every day at the same places. Record them, note how long your stove was running. What else can we do.... at least your not getting smoke back now.

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Staci Kopcha

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Location: Western Washington State

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thomas rubino wrote:
Ha Ha been visiting a Washington state green store lately ?

Hi Thomas-
No, no green stores - maybe my kombucha brewed too long. ;)
I will try a log book, with temp readings and weather info. See if any patterns develop.
S.

Staci Kopcha

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Burn ban over!

SO, I took readings before lighting this afternoon. And just took readings 2 hours after solid burn-time (will take more at 3 and 4 hours)
Note: All readings are in degrees F. All readings are taken 3 times, for verification. All may be variable +/- 5-10 degrees

Outside: cold and sunny/clear

Time: zero 2 hours

outside temp 48F 42F
Barrel side 73 197 (top is over 475)
manifold 76 97
bench 1 94 94
bench 2 81 78
chimney 70 96
outside chimney 79

Graham Chiu

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Staci, do you know how much mass you have in your RMH, and how much wood in weight you burn over that period?
And the room temperatures?

Staci Kopcha

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Graham Chiu wrote:Staci, do you know how much mass you have in your RMH, and how much wood in weight you burn over that period?
And the room temperatures?

Hi Graham,
I honestly have no idea how much mass there is, nor (at this point) how I could calculate it. I am guessing it would have been something that I should have considered beforehand...weighing a bucket of wet cob, letting it dry and then weighing that, and then recording how many buckets of cob I used. Also, doing something similar to how much mass (for me, bricks and rocks) I put in.

I am not sure of how much wood I have burned over a period, but that would be do-able.
Beginning room temp was probably low 60's. Now... upper 60's- 70.

Staci

Staci Kopcha

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Last readings for today:

3 hours 4 hours

barrel side 199 200 (top of barrel is over 475)
manifold 99 109
bench1 98 98
bench 2 79 81
chimney-*inside room 97 90

*opted not to roof climb any more in the dark for tonight, so no outside chimney temp.

Wood has been reading 20% range with my moisture tester.

Gerry Parent

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Hey Staci, Having a wood moisture of 20% along with a top of barrel temp of 475F for over a 4 hour burn (not really that high), I would say is why your mass is heating up so slowly. If you can't burn wood less than lets say around 14% then cutting the wood up into smaller pieces would definitely help increase the surface area of the burn and increase the heat output. Mind you, you'll have to feed it every 10-15 minutes but this would at least prove if this was the case. If you can really get your stove going fast and furious in this way, the top of barrel temp should get over 800F in a short while.

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Graham Chiu

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Since you're using the same wood combination all the time it doesn't make sense that one day your RMH works and the next day it doesn't. So, this suggests something outside is affecting the draft.
Can you measure the draft with a tissue near the feed tube? Or a match?

Staci Kopcha

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Location: Western Washington State

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Graham Chiu wrote:Since you're using the same wood combination all the time it doesn't make sense that one day your RMH works and the next day it doesn't. So, this suggests something outside is affecting the draft.
Can you measure the draft with a tissue near the feed tube? Or a match?

I am thinking that must be it. The weather is due to change back to our "normal" rainy wet stuff today. If RMH function returns to "normal", it will be an easy conclusion. I will take measurements.
I can try to judge draft before I light it (candle flame).
Question is, IF it is weather, and is bound to happen periodically, is there a way to manage it? Or is it something I just have to weather out (pun unintended).

Thanks!
Staci

thomas rubino

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Staci; If it is weather, then you might try making your chimney taller outside. I know the costs involved with that, to do it right. If needed, you might just try and stick a piece of plain stove pipe on top and see if it has an effect. (remember it will not be insulated ) If it seems to work and you can't afford a new piece of insulated pipe, then insulate your own. Ugly but wrap it with insulation and slide a larger pipe over top. Later if that solves your problem you can save up for a shiny new metalbestos pipe.

For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!

Graham Chiu

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Do you have weather data for your immediate region? In particular wind speeds? If not, can you measure it?

Caleb Mayfield

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My feeling is weather, and possibly wind, is the primary culprit. I've been noticing with my RMH that winds from a particular direction will cause it to draft differently (slower) and that some days it seems like it just won't heat up like it does at other times. High, gusty winds, or damp/high humidity days seem to do the same. It does heat up, but we really struggle to get it roaring. The wood isn't the driest either. Another year with it split would be spectacular in my case.

Anyway, I also have noticed a trend on mine that if I start it hot, it will burn hot. Meaning I start it with a load of stuff split down to 1/4"-1/2" and use a good handfull, maybe two, of fat wood shavings it will fire up hot and fast, then I feed it smaller stuff for the first 5-10 minutes. That gets my drum upwards of 600 F (hot for mine). Then I start feeding it normal 1"-2" sized stuff and it chooches right along between 550-600 F.

If I load it up with larger stuff off the bat, or less fat wood it takes longer to get warm and I struggle to get it up to 500 F. It gets warm and gives off the heat we need, and looking at the chimney it's burning clean, just not as well as a good hot start.

Just a thought.

Good luck!

James 1:19-20
Not all those who wander are lost - J. R. R. Tolkien

Staci Kopcha

pollinator

Posts: 231

Location: Western Washington State

posted 6 years ago

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Okay, with the burn ban lifted, i was able to do a morning burn today. I am getting better results now.
Could be too early to tell: I will verify again tonight.

Here is my thoughts/theory:
The burn ban resulted from some sort of weather pattern that caused the air to be stagnant. (pressure??)- something out of the ordinary weather pattern.
This weather must have impacted my burn. Mostly, by affecting my draft. Causing it to suck the air through the system too fast and therefore not heat the mass.

**Wondering what can be done to increase efficiency during these times??

Today:
Outside temp. is about the same (53F), there is some mild wind. (Overnight temps. were warmer, no frost or freezing as had been)
My starting temps were higher, but even with that, it still got higher readings.
(Also of note: My temp reader doesn't read beyond 475. So I cannot know the true temp of barrel top.)

0 hours 3 hours

barrel side 82 208 (top of barrel is over 475)
manifold 91 130
bench1 99 113
bench 2 78 88
chimney-*inside room 74 92

So it takes a day for light to pass through this glass? So this was yesterday's tiny ad?

A rocket mass heater is the most sustainable way to heat a conventional home

http://woodheat.net