# Chimney questions



## warno (Nov 11, 2016)

I'm running a homemade OWB that's about 10 feet from my garage in its own shed. the chimney is pretty much at that 10 feet mark from the garage. and is about 10 feet off the ground at the top. well  when I light the boiler for a batch burn it takes about 30-45 minutes to start burning more clean and getting less smoke out of the chimney.

My problem is while I'm waiting for the smoke to clear up it gets driven back down to the ground and drifts across the yard into the neighbors property. so it's my understanding that "smoke" is naturally heavy and falls to the ground anyway but will adding 6 more feet of chimney help my situation, or will the smoke still hit the ground and drift to my neighbors?







So my garage is in red.  boiler shed blue, chimney black.

Peak of the garage is about 15 feet high. the chimney is about 10 from the ground now. if you draw a line to the garage roof at 10 feet is about 12 feet from the opening of the chimney. so will 6 more feet help me get the problem smoke up and out of the yards?

Hopefully all this makes sense.


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## huffdawg (Nov 11, 2016)

My chimney is around 26 ft high . It seems to depend on the wind and out side temps which way the smoke goes . But the smoke from mine only seems to last a few mins. till it starts gasification


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## warno (Nov 11, 2016)

Mines pretty heavy smoke because the "traditional" style boiler I'm running. it does clear up though, it just takes awhile. 

Does your smoke ever drop or does it start at the level it exits the chimney?


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## huffdawg (Nov 11, 2016)

Ya it drops when it's cold out and no wind.. sometimes from other neighbours it gets really smoggy .. neighbors with wood stove don't seem to know how to run them.. they load them up and dampen them down


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## warno (Nov 11, 2016)

I would hate to see their chimneys inside.


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## stee6043 (Nov 12, 2016)

I think you're probably going to struggle to find a solid solution here.  Another 6' of chimney probably isn't going to change much of anything.  Another 20'?  Maybe.  

Where I live they require OWB's to be quite a long distance from homes and lot lines to prevent this.

Regardless of the type of wood burner being used I'd be pretty upset if I were your neighbor.  I've been smoked out by leaf burning/bonfires before and it can be highly unpleasant.  It's not just their yard you're filling with smoke...


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## warno (Nov 12, 2016)

stee6043 said:


> Regardless of the type of wood burner being used I'd be pretty upset if I were your neighbor.  I've been smoked out by leaf burning/bonfires before and it can be highly unpleasant.  It's not just their yard you're filling with smoke...



I understand where you're coming from. I wish I would have built a gasifier. I was quite embarrassed last year by the amount of smoke I was putting out. but  this year I'm batch burning to charge storage tanks in my garage. so after the intial smoke starts clearing then it's clear for the rest of the burn. but I understand what you're saying about the smoke in general. 


This  is my back yard from inside the house. you can see the proximity of the boiler shed to the garage. you can also see the proximity to the neighbors house across the alley. so would any extra chimney height help keep the smoke going upwards? also the boiler is running in this picture. so it does clean up, it just takes a little bit.


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## Bad LP (Nov 12, 2016)

I'm a guy that is really for many personal freedoms including wood burning and doing what you want on your property. You're in what looks like a pretty tight lot with neighbors all around you. 

Sorry but I'm not a fan of that arrangement in such close proximity to others.  A little wood stove smoke is one thing. Wood boiler smoke is another. I've seen some pretty nasty smoke coming out of some of them in areas much less populated and I was glad I was not a neighbor to it.

If you were my neighbor we would have a serious problem after what you are describing going on. Your stink doesn't belong inside my house and vise versa.

IMO 6 more feet of stack isn't going to do a damn thing.


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## warno (Nov 12, 2016)

So if it takes a gasifier 5 minutes or so to clear I guess I'm not hating what mine is doing too  much.  Apparently I need to focus  more on how I load the fire box. when I was questioning my smoke output I had loaded the firebox pretty tight. and since I'm burning up the split oak timbers I have it will obviously stack in there with little room for air movement. tonight I tried to seperate the splits and get good air flow through the box. 

well 10 minutes after lighting the newspaper here's what I have coming from the chimney. you can see the slight smoke column rising outlined in red. 






And as I'm typing this is only getting less and less. now it appears to be more vapor in the air from the chill rolling in tonight.


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## brenndatomu (Nov 12, 2016)

warno said:


> stack in there with little room for air movement. tonight I tried to seperate the splits and get good air flow through the box.


This is how you are supposed to load a modern "EPA" style stove too...gotta give the secondary air tubes a lil room to breath...


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## huffdawg (Nov 12, 2016)

Don't look to bad to me.. can u post a vid in the daylight?


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## warno (Nov 12, 2016)

I'll try to get one tomorrow for you.


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## mike van (Nov 13, 2016)

Even with a gasser, long after the smoke has cleared there is still a strong smell of something being burnt.  People have been forced to take these out, you can't ruin someones life, home, property, etc. because you choose to burn wood. You sound like you want to be a good neighbor, i'd look into moving it if you can? 50 ft of chimney would help [remember the 100+ ft brick smokestacks]  You're at a croosroad for sure.


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## woodsmaster (Nov 13, 2016)

Couple of things that may help. When your fire is getting towards the end of a burn shut it down so that you have some charcoal left to start the next fire. 
It may get going quicker and smoke less. also be selective when you start your fire. Do it when they are gone , when they are sleeping. or when the wind isn't blowing towards them.


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## woodsmaster (Nov 13, 2016)

Could also try making a small fire at first to get boiler warmed up then add more wood after its going good.


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## woodsmaster (Nov 13, 2016)

i would definitely add some more chimney too.


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## Bootstrap (Nov 13, 2016)

That stack is not tall enough. More chimney would be a good thing for sure. I would add at least 15 more feet, which would need some kind of support as well. Some towns have ordinances that require the chimney to be taller than surrounding structures. That wouldn't count structures that are erected on a variance, but does include normal structures in the immediate area.
 At the very least, it might help the smoke from clearing your direct neighbors. It'll also give stronger draft. If your fire is that smokey for that long then your wood is too wet.
I encourage you to reduce smoke before the town gets on you.


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## warno (Nov 13, 2016)

All good advice. I do believe when I started this thread that I packed the fire box to tight and it simply couldn't get air moving inside. 

I know there's at least 2 others in my area that have wood stoves and that burn all winter long. I grew up with a wood stove that dad always ran every winter so I know the smell. I for one love the smell of burning wood. I don't like the smoke but once it's cleared up the smell is almost nonexistent. and if my stack isn't smoking the neighbors in the area couldn't tell if it's me or the other 2 people. 

I can assure everyone the wood I'm burning is not wet by any means. it's oak timbers cut to 30" long that were sitting in a pile for over 5 years then I split them and they say for another year. they  are testing well below 20%. my boiler is forced induction so draft isn't a huge concern but I know more draft helps. 

When I built this boiler I asked our fire chief of our town had any ordinances against them and he said no because we dont have the man power to enforce it. so with that being said I don't want to be the guy that gets them banned in my town. last year I smoked everyone out with my idling and was embarrassed as hell about it. but this year I added 750 gallon of storage to start running batch burns which I've already noticed helps with efficiency. I'm just going to get it burning cleaner quicker. 

I do try to light my fires as early in the morning as possible that way its cleared up before the neighbors get up and running. I seem to be the early bird in the area so that helps. if its not really morning I light up, it's right before bed when everyone elses lights are out. 

So I will try to get some more chimney and I have adobe other ideas to modify my firebox a bit to hopefully help combustion.


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## Bootstrap (Nov 13, 2016)

warno said:


> When I built this boiler I asked our fire chief of our town had any ordinances against them and he said no because we dont have the man power to enforce it. so with that being said I don't want to be the guy that gets them banned in my town.
> I do try to light my fires as early in the morning as possible that way its cleared up before the neighbors get up and running. I seem to be the early bird in the area so that helps. if its not really morning I light up, it's right before bed when everyone elses lights are out.
> 
> So I will try to get some more chimney and I have adobe other ideas to modify my firebox a bit to hopefully help combustion.



Yea it would suck if you were the reason for more regulations.

You like wood smell but not everyone does. I don't mind the hint of wood burning but I cant stand a strong odor in the house. On the other hand I love burning wood.
I catch my furnace smoking once in a while and I immediately go down stairs and open it up. It almost always has some smoke coming out, but rarely belches tons of smoke. I have good neighbors(except for one), and I want to keep it that way.

A few years back I had a huge fire pit outside. I used to burn pallets and the fire would be 10' high or bigger at times. Neighbors never said a thing. Well a few years go by, and the neighbors across the street started getting up there in age. They still didn't say anything....that is until one day my dad had a great idea to burn leaves in the pit. The smoke could probably be seen in the next town before I realized what was going on. Well it was too late. Even though the smoke was going over their house, they threw a fit over it and called the fire department. They didn't seem to care much about the fire, it was the smoke that they couldn't stand.
 From that point forward, they called the fire department every time I lit a fire. We still don't talk, years later. I decided to dismantle the pit and made an outside fireplace with a chimney in a different spot. I don't think they can even see the fireplace and it doesn't smoke anyways.
So point in case, once you piss someone off, they will be all over you every time after that initial issue. So try to avoid the initial issue. I'm a huge believer in your yard is your yard. But there are costs of living near people.


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## warno (Nov 13, 2016)

Yes I am in the same boat. all my neighbors but one are very nice. so I want to try my best to keep it that way. 

My neighbor across the alley is the one I worry about. she wife in the house saw me wrong the front of my truck through the edge of the alley easement grass while banking a trailer into my drive. will from that day forward, which was in 2010, I haven't liked them. in fact she put a pile of bricks, chunks of concrete, and landscaping timbers in that area I swing the front tires through. now keep in mind this is on city property. I in no way shape or form went through their actual yard. so I'm trying to avoid pissing them off for any reason with my smoke.


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## Fred61 (Nov 13, 2016)

One look at the barometer and you will know is the smoke is going to go up or linger at ground level. That is, once the smoke is warm and lighter than the atmosphere. Cold clear (sunny) days it will rise. Rainey overcast days (heavy moist air) will cause it to drop.
I believe that adding height to your chimney will help by giving you additional draft. The cold smoke generated when you first start your fire will tend to sink so hopefully you'll develop a technique to heat the firebox as quickly as possible.

Hopefully your design is such that you will be able to burn hot and get the smoke burned in the firebox on your batch burns and not lose half your heat up the stack.

If I start my EKO the conventional way that most folks do here which is "up burning" with all dampers open including the lower door it will easily smoke up a radius of a quarter mile. Luckily NO NEIGHBORS. The technique I developed is to save a good amount of charcoal from the last burn, rake it over the nozzle, add 5 or 6 small splits, light charcoal from below with torch and when it is glowing start fan,shut the door, and shut the bypass. I usually open the lower door within 10 or so seconds and usually, without fail will see it gassing. It will be very wimpy gassing but that's all I need. I can go away and come back 30 minutes later to find a nice fire with just about all the pieces on fire and fill the fire box. Using this technique, I don't get any smoke at all coming from the stack.

One thing more: I have forgotten what your firebox is like. Could you add more firebrick to keep the fire from cooling due to contact with the cold inner wall and concentrate the heat. Smoke coming out of the stack means you're not burning it up in the firebox because the fire is too cold.


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## warno (Nov 13, 2016)

Fred61 said:


> One thing more: I have forgotten what your firebox is like. Could you add more firebrick to keep the fire from cooling due to contact with the cold inner wall and concentrate the heat. Smoke coming out of the stack means you're not burning it up in the firebox because the fire is too cold.



My firebox is only half, the upper half, submerged in water. I have a heat exchanger that is a 6" X 10" rectangular box that is about 7 feet long above the firebox that is also under water. my fire box bottom is filled  with refractory cement, about 175 pounds, and refractory brick. the lining goes up just over the water line in the box. my air flows in the ash pan back then  up under the fire.


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## Fred61 (Nov 13, 2016)

warno said:


> my air flows in the ash pan back then up under the fire.


That question arose after I posted.

Any way you can experiment with air flow directing some to the middle or top of the fire?


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## warno (Nov 13, 2016)

I was thinking about that tonight actually. I had a system to get preheated air over top of the fire in attempt to have secondary flames happen above the fire. But I don't think with a water jacket directly above the fire I can get it hot enough. I've been thinking about adding  a plate at the top of my fire box to insulate from the water jacket and try the secondary air again.


I did get some  videos but the sun was going down so it's not very good. I'll try again tomorrow morning.

This is about 18 hours after the last burn. my flue temp sensor shuts everything down at 240F. this is a pretty good temp for the fuel to be burnt and my storage not stealing alot of great from the boiler water. Here's what I am left with. 






my storage was down around 125F and here's my boiler. the A419 is my water and the other is my flue. this is before startup .






Here's my fuel load. Some newspaper, kindling, and the oak timbers.






And in case the question of dryness is there still






So I lite the fire and this is right after lighting



And here's 10 minutes after lighting


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## Fred61 (Nov 13, 2016)

Boilers designed to burn wood only have the air supply directed at the base of the fire and not below. Boilers designed to burn both wood and coal have air coming from below but they don't work well with either fuel. Coal needs combustion air below the fire but not wood.


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## warno (Nov 13, 2016)

So I should direct my air flow into the coal bed for a better burn?


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## mike van (Nov 14, 2016)

Fred might be on to something there = My Harman had the same wood / coal setup, wow what a smoker it was.


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## woodsmaster (Nov 14, 2016)

I would split the wood a little smaller to get the fire going and up to temp quicker, and try to leave a little more charcoal for starting the next fire.


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## Fred61 (Nov 14, 2016)

My assumption is that you will not be able to burn the smoke if the oxygen is depleted from the combustion air by the time it reaches the middle or top of the load regardless of how far your inlet damper is open.


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## warno (Nov 14, 2016)

My dad has been telling me basically the samething. on his wood furnace in his basement the air damper, natural draft, pulls air directly into the coal bed from the front of the furnace. but his furnace has  the smoke channel above which means his smoke leaves the front to go over top of the fire to get reburned before leaving up the flue. maybe I should redirect my air flow into my coal bed and see what happens.


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## Fred61 (Nov 14, 2016)

That channel needs to have enough air and enough heat to ignite the gasses. You need both. His apparently has them if it is not a "smoker".


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## warno (Nov 14, 2016)

Dad's furnace is about 30 years old or so. he's  got about 30 feet of chimney through his house so draft is not an issue there. dad can start a new fire and within minutes is burning clean and clear.


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## warno (Nov 14, 2016)

I took some more videos this morning.

This is right after lighting. 



10 minutes in



25 minutes in from inside the house


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## stee6043 (Nov 14, 2016)

I must say, warno, you're probably one of the most caring suburban wood burners out there!  Most folks wouldn't put half of your effort into understanding their wood burners and trying to improve.

Keep up the good work.  If I were in your shoes I'd combine a couple of the suggestions above - 1.) put more chimney up, as much as you can handle, 2.) start your fires with small, super dry splits and 3.) try to leave some coals from the prior fire in the bottom if you can.  Many of us gasser owners use a cheapo 110v timer to accomplish #3.  It can be a big helper...


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## warno (Nov 14, 2016)

Thank you. I'm trying to do my best. I know the smoke is offensive and I don't want to be the problem  in the neighborhood if I can avoid it. But, having a homebuilt unit allows me to change and try new things without voiding any warranty.

All my control is based off my flue temp. it's a truly simple control system  though. it only uses one relay to shut things down after flue temp gets back down to my "shut down" setting. so if I find a setting  that leaves a good amount of charcoal behind I'll stick with that. I'm thinking that's around where I'm at now with 240 shut  down temp. I'm  going to try changing my air input soon.


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## brenndatomu (Nov 14, 2016)

So your secondary air is routed into the top of the firebox? If so then yeah the water cooled steel is probably keeping things too cool to fire off the reburn. It takes somewheres 1200* to make that happen. The way most newer "EPA" style wood furnaces are setup is that the firebox is totally insulated with firebrick on the sides and a ceramic insulation board at the top that sets right on the secondary air tubes. There is not much heat to be had directly from the firebox, rather they want the temp up as high as possible to burn everything off, then rely on the heat exchanger to capture heat from the flue gasses on their way out...much like your set up I believe.
That ceramic insulation board can be had on fleabay and the like in many different sizes...not that cheap though...


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## warno (Nov 14, 2016)

I kind of hate to do it because I'm already seeing flue temps up to 600 degrees but I could completely line my fire box with fire brick to insulate it completely from the water jacket. I mean the water would get some radiant through the brick but I would be relying solely on my heat exchanger to get 90%, or better,  of the heat from the flue gasses. I do have a turbulator idea that I can implement. how much would this help? my firebox started life as a 120 gallon propane tank, so it's completely round inside.


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## brenndatomu (Nov 14, 2016)

600* is about where my furnace runs when the intake damper is wide open. How many CFM is your combustion fan? Maybe with a taller chimney you could line the firebox, and then rely on natural draft induction. That would slow the exhaust down more and maybe give you more heat and lower chimney temps? Is the secondary air forced air too?


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## warno (Nov 14, 2016)

The secondary tube was fed with a fan as well. which is probably why it wasn't firing.


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## brenndatomu (Nov 14, 2016)

warno said:


> The secondary tube was fed with a fan as well. which is probably why it wasn't firing.


I bet you're right


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## warno (Nov 14, 2016)

Should the secondary tube be natural draft only or can some induced air flow be ok?


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## brenndatomu (Nov 14, 2016)

warno said:


> Should the secondary tube be natural draft only or can some induced air flow be ok?


I would think you would want natural draft only (for both primary and secondary) so the air velocity would be low enough to pick up as much heat as possible...(remember that 1200* mark)
And like I said, slowing things down will help your HE better work too. You may be surprised how much a taller chimney would improve natural draft....you could just scab up some cheap single wall stove pipe to extend the chimney temporarily for testing purposes


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## warno (Nov 14, 2016)

I understand more chimney will help draft. the way my boiler is built I would have to do a few modifications to get it to natural draft. not that it can't  be done it would just take some rethinking of the parts on hand.


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## warno (Nov 15, 2016)

I tried to dig up the best picture I have "side view" of when I was building my boiler to show where my air flow is entering. 

So here it is. you can see where my water jacket falls on the fire box, my heat exchanger box, and my air flow pipe. the blue arrow is showing current air flow coming in under the fire grate (red line).







And this is what I'm thinking about doing to get my air flow up into the back of the coal bed. I have 2 weld  elbows that I'm going to add in to get the air up above the fire grate. 






I know it's rough drawings but will this possibly help with getting the air where I need it?


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## maple1 (Nov 15, 2016)

This is partly some wild speculation, but I'm thinking you might have something there that might be able to be turned into something with some gasification to it. Via creative use of firebricking, & airflow routing.


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## brenndatomu (Nov 15, 2016)

warno said:


> I tried to dig up the best picture I have "side view" of when I was building my boiler to show where my air flow is entering.
> 
> So here it is. you can see where my water jacket falls on the fire box, my heat exchanger box, and my air flow pipe. the blue arrow is showing current air flow coming in under the fire grate (red line).
> 
> ...


So the secondary air pipe will run through the coals before turning up to the top? That would make for some hot coals once you get to that point in the combustion cycle (probably coals there all the time once full time burning is commenced)


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## warno (Nov 15, 2016)

Yeah. my secondary pipe flows in through my fire grate, which turns red in a hot burn, and then turns up above the fire. 

In my drawing though the air flow pipe I was refering to is my primary air.


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## TCaldwell (Nov 16, 2016)

As stated the placement of the primary should be directed at the wood, not under it. Preheating the secondary is also optimum, can you mark up a photo of the secondary air flow and flue entrance. Secondary air requires time to mix with the wood gas and combust in a insulated or refractory area. Because of your boilers relatively low overall output this area wouldn't have to very large, can you allocate 25pct of the overall firebox to this? Also the primary and secondary air need to be controlled or allocated in a adjustable way like dampers  for tuning pirposes


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## warno (Nov 16, 2016)

Ok so as of right now here how air flows through my boiler, into the exchanger and out the flue. the fan blows air in the ash pan which comes up through the front of the fire grate, it then rises to the top of the fire box and had to go under the water filled baffle then into the heat exchanger. it then travels forward where it turns and travels back, then exits out the flue. 






This is what my heat exchanger looks like 






And here is how my secondary air is coming in. 

It enters the boiler right next to the primary air but is driven into the fire grate via this drop down piece






Then it travels forward in the 3 left tubes of the grate and turns at the front to go back the 3 right tubes and up into the branch.






And here's the branch with the holes marked in circles. 






The branch is mounted right below my water cooled baffle which maybe causing too much cooling preventing any secondary firing. would it be wise to move my secondary branch out over top of the fire? just to see if that helps before completely rebuilding everything else.


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## Fred61 (Nov 16, 2016)

Correct me if I'm wrong but what I see in the non smoking (gassers) boilers is that the secondary combustion has already occurred by the time the gasses reach the point where the steel vessel is exposed to the fire. It may not be possible to get secondary burn if the water jacket is cooling the gasses. On my EKO the smoke is already burned by the time it goes through the heat exchanger.

Unless this experiment is easy and cheap to accomplish it may not be worth the time and money.

Also, the fire needs to burn with a minimal amount of air. I have the combustion fan dialed down so slow it barely starts but the flame in the lower chamber would be described as "violent" when viewed at full burn.


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## warno (Nov 16, 2016)

The cheap part of modifications I can accomplish, easy on the other hand that's another story. anything I do to "modify" from here until I shut down is  going to require me crawling in my on top of my 100+ degree refractory surrounded by a jacket of 150+ degree water. it's hot in there is what I'm getting at.   not that I can't handle the task, it just won't be "easy". 

Later today I'll draw up another sketch of a different idea I've been kicking around for you guys to review. it will be a natural draft setup with a smoke channel above the fire with air introduced into it.


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## maple1 (Nov 16, 2016)

How do the gases get out in that last pic? Hard to tell, do they drop below that round looking cross piece thing? And does it have a bypass damper? Guessing not?


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## TCaldwell (Nov 16, 2016)

Don't know if you have the room in the burn chamber to put a second one above it, but could you add on to the back( garn style)


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## warno (Nov 16, 2016)

maple1 said:


> How do the gases get out in that last pic? Hard to tell, do they drop below that round looking cross piece thing? And does it have a bypass damper? Guessing not?



The gases in the secondary branch come out through the holes that I circled. if you are referring to the gasses leaving  the firebox they must drop below the water cooled baffle, then go into the heat exchanger. I do not have a bypass damper it's just air in flue gases out. 



TCaldwell said:


> Don't know if you have the room in the burn chamber to put a second one above it, but could you add on to the back( garn style)



 it would be easier to build down then it would up or back. building down I can avoid the water jacket.


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## Fred61 (Nov 16, 2016)

warno said:


> The cheap part of modifications I can accomplish, easy on the other hand that's another story. anything I do to "modify" from here until I shut down is  going to require me crawling in my on top of my 100+ degree refractory surrounded by a jacket of 150+ degree water. it's hot in there is what I'm getting at.   not that I can't handle the task, it just won't be "easy".
> 
> Later today I'll draw up another sketch of a different idea I've been kicking around for you guys to review. it will be a natural draft setup with a smoke channel above the fire with air introduced into it.



About the temperature of a crock pot. Don't forget to bring the carrots in with you!


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## brenndatomu (Nov 16, 2016)

warno said:


> would it be wise to move my secondary branch out over top of the fire?


I would. Move it up higher in the firebox and then forward too (toward the loading door) which probably means going lengthwise instead of crossways


Fred61 said:


> About the temperature of a crock pot. Don't forget to bring the carrots in with you!


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## warno (Nov 16, 2016)

brenndatomu said:


> I would. Move it up higher in the firebox and then forward too (toward the loading door) which probably means going lengthwise instead of crossways



Ok that's easy enough to do. I'll try that out.


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## STIHLY DAN (Nov 16, 2016)

What is the heat exchanger heating? The outside of the water jacket?


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## warno (Nov 16, 2016)

In this picture you can see the heat exchanger above the fire box







And here is the water jacket walls going on. 






The heat exchanger is like the tubes in a gasifier  boiler going through the water. but instead of pipes I used a big box.


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## Bootstrap (Nov 17, 2016)

I hate to say it, but a considerable reduction in smoke might not happen. Without some kind of reburn prior to the heat exchanger I don't see how. Insulating the fire box better would improve, and increasing stack height might help get more of that smoke away from the area. Those two things might be enough to please everyone.


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## warno (Dec 7, 2016)

So I did some modifications to my secondary air piping today. I have positive draft pulling air into the inlet of the pipe but still no secondary flames, not even alittle. I seal the fire box opening with a piece of plywood with a hole drilled to see inside and the secondary piping inside is glowing red but no flame coming from the holes. so its drawing air and it's hot but no flames. I'm wondering if the air is having to travel too far too get to the holes. I mean the air had to flow all the way forward them to the back of my fire grate then up into the pipe with exit holes. it's almost 6 feet of pipe before it can exit out the holes inside the fire box. should I shorten this distance? would that help anything? 

Some pics of the new branch with exit holes


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## brenndatomu (Dec 7, 2016)

I still have a bad feeling that the "cold" water cooled firebox wall right there is killing the temps that it normally takes (1200*) to make the magic happen. I wonder if you could stuff a piece of 1/2" ceramic insulation blanket above the tubes temporarily to test this theory...or maybe some rockwool (roxul) type material


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## Fred61 (Dec 7, 2016)

I think you're just blowing air into smoke that is not hot enough to ignite. In fact your primary fire might not be hot enough to heat the top of the fire even if your secondary air was directed within an inch of the primary fire.

Is there a way you could build a ceramic tunnel to house your primary fire with a nozzle on top and direct primary air to the center of the blaze so that it burns like you were blowing on an ember to start a fire so that it glows like a cigar. In other words, very little air. That would send super heated gas through the nozzle and perhaps re-ignite above the tunnel. Only a small amount of secondary air would be needed as a large amount of air would have a cooling effect. It also should be directed to the nozzle area.


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## warno (Dec 7, 2016)

I'll put a stainless steel plate over top of the tubes to protect them from above and test the theory again. 

 I should add that when I was trying to test the secondary flames i shut down the inducer fan and opened my ash pan door a crack to get natrual draft induction.


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## brenndatomu (Dec 8, 2016)

warno said:


> I'll put a stainless steel plate over top of the tubes to protect them from above and test the theory again.


I'm sure that will help but I dunno if it will be enough really...stainless is gonna have a *very* low R value compared to the 1/2" - 1" thick ceramic insulation board that many/most secondary burn stoves use in the top of their fireboxes.
Easy enough to try I guess...


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## JohnDolz (Dec 8, 2016)

Bootstrap said:


> I hate to say it, but a considerable reduction in smoke might not happen. Without some kind of reburn prior to the heat exchanger I don't see how. Insulating the fire box better would improve, and increasing stack height might help get more of that smoke away from the area. Those two things might be enough to please everyone.


I know there is a lot of concern around keeping the neighbors happy, keep in mind that they may not appreciate looking out the window and seeing a stack sticking way up in the air. The smoke only seems to be an issue when you fire up, if you create an eyesore you have a year round issue to deal with.


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## warno (Dec 8, 2016)

JohnDolz said:


> I know there is a lot of concern around keeping the neighbors happy, keep in mind that they may not appreciate looking out the window and seeing a stack sticking way up in the air. The smoke only seems to be an issue when you fire up, if you create an eyesore you have a year round issue to deal with.



I had that thought as well. I'm trying to get things better with the stack I have at the moment because materials for trail and error are cheaper then $75 per 3 feet of stack pipe.


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## Coal Reaper (Dec 23, 2016)

let to the party here!

Curious, how is the stainless plate working?  Its above your secondary air, correct?  I was thinking that would help is I read through this thread.  Stainless will hold up to the heat well and you can let fly ash accumulate on top of it to insulate against the cold walls of the firebox. 

Have you tried raking all your coals to the back before reloading and starting your fire from there?  Doing that and stacking your wood tight might get you a nice 'cigar' burn starting from the back where your primary air enters allowing it to get hot as fast as possible.

I would try to keep as high of temps as possible where the burn is in the firebox and let the heat exchanger transfer the BTUs to the water.

Where is your fan located?


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## warno (Dec 23, 2016)

I haven't had much time to mess with things as of lately. I need to relocate my primary air ducting still and add the stainless plate above the air tubes. I just haven't had much time to do it since getting my new job.


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## brenndatomu (Dec 23, 2016)

warno said:


> new job


Congrats!


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## warno (Dec 23, 2016)

brenndatomu said:


> Congrats!



Thank you. It's going great as well.


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## STIHLY DAN (Dec 23, 2016)

If the secondary pipes are glowing red they are hot enough. What is your draft? Seems to me the heat is good but not enough air is getting to the secondaries.


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## warno (Dec 24, 2016)

STIHLY DAN said:


> If the secondary pipes are glowing red they are hot enough. What is your draft? Seems to me the heat is good but not enough air is getting to the secondaries.



I haven't tested my draft but with only 6 feet of actually chimney length I doubt is very much. I'm going to put a low cfm fan on the secondary intake and push some air through the tubes to test them out.


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## STIHLY DAN (Dec 24, 2016)

That would explain it.


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