How can I achieve secondary burns in this wood stove?

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Ahmet94

New Member
Oct 13, 2022
13
İstanbul
Hi, last year I got this wood stove. This is a cast iron model approximately 120 Kg (260 pounds).

It has 3 windows (unfortunately there wasn't much single windowed options here in Turkey). One on front 2 on sides. Actually it even had one in the back but prior to ordering I told them to replace it with cast iron as it was optional.

The back part which is removable, looks like a double walled structure. It has 10 holes in the firebox part but you can't see the anything. The holes don't just go out of the stove. On the exterior of wood stove, back side has 2 venting holes. Again you can't see the firebox from the outside. So my guess is it's double walled. I used a hair dried at full speed to test if it took air in, and yes it did.


There is also a secondary air intake on top of the glass.

The shape of the stove is rounded by sides. The back and front isn't same sized. So i realised the baffle (which looks cast iron around 3mm) isn't well insulated. Because it's a square while the stove isn't a square. And some smoke actually runs form the sides. I ordered 8mm gasket and i will insulate it soon.


Now my question is this stove has a taller firebox than models I have seen on the Web and YouTube. The baffle is really way above. And also there is a good distance between the top of the stove and the baffle (around 10cm~). Would it give secondary burning?

If I had the skills I would add a stainless steel tubing to the baffle and drill the back of the stove.


This model doesn't come with firebricks as its already very sense cast iron, i thought about adding firebricks to the side windows as they are not small. To increase overall firebox temperature to achieve secondary burning.

Or i could add fire bricks to the back side and try to drill the bricks so that the vent holes can deliver oxygen by negative pressure.

Does it make any sense to add fire bricks? I will add pics with measurements on them.

My set up is there is 1.55cm of pipe goes up then there is like 35cm of horizontal pipe which connects to a 304L SS 90 degree elbow flue and it goes 7m SS flue up in a bricked chimney. It's not a liner, 0.4mm SS flue with a wind blocking hat.


The draft is phenomenal. It's a single walled flue but it has bricks around it. And the top 6 meters is well insulated... There is just 70cm of flue sting naked without insulation. But whether don't go below - 5C here.

I burn hard oak seasoned. But when I run out I will probably buy briquettes made from saw dust. They are a bit expensive but i can't really deal with bugs from wood. I risked enough.
Wish it was easy to store wood in an apartment.

This is the thing but my sides are glass. I will ask for cast iron parts.
 
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Hi, last year I got this wood stove. This is a cast iron model approximately 120 Kg (260 pounds).

It has 3 windows (unfortunately there wasn't much single windowed options here in Turkey). One on front 2 on sides. Actually it even had one in the back but prior to ordering I told them to replace it with cast iron as it was optional.

The back part which is removable, looks like a double walled structure. It has 10 holes in the firebox part but you can't see the anything. The holes don't just go out of the stove. On the exterior of wood stove, back side has 2 venting holes. Again you can't see the firebox from the outside. So my guess is it's double walled. I used a hair dried at full speed to test if it took air in, and yes it did.


There is also a secondary air intake on top of the glass.

The shape of the stove is rounded by sides. The back and front isn't same sized. So i realised the baffle (which looks cast iron around 3mm) isn't well insulated. Because it's a square while the stove isn't a square. And some smoke actually runs form the sides. I ordered 8mm gasket and i will insulate it soon.


Now my question is this stove has a taller firebox than models I have seen on the Web and YouTube. The baffle is really way above. And also there is a good distance between the top of the stove and the baffle (around 10cm~). Would it give secondary burning?

If I had the skills I would add a stainless steel tubing to the baffle and drill the back of the stove.


This model doesn't come with firebricks as its already very sense cast iron, i thought about adding firebricks to the side windows as they are not small. To increase overall firebox temperature to achieve secondary burning.

Or i could add fire bricks to the back side and try to drill the bricks so that the vent holes can deliver oxygen by negative pressure.

Does it make any sense to add fire bricks? I will add pics with measurements on them.

My set up is there is 1.55cm of pipe goes up then there is like 35cm of horizontal pipe which connects to a 304L SS 90 degree elbow flue and it goes 7m SS flue up in a bricked chimney. It's not a liner, 0.4mm SS flue with a wind blocking hat.


The draft is phenomenal. It's a single walled flue but it has bricks around it. And the top 6 meters is well insulated... There is just 70cm of flue sting naked without insulation. But whether don't go below - 5C here.

I burn hard oak seasoned. But when I run out I will probably buy briquettes made from saw dust. They are a bit expensive but i can't really deal with bugs from wood. I risked enough.
Wish it was easy to store wood in an apartment.

This is the thing but my sides are glass. I will ask for cast iron parts.

so I clicked the link.. not to be rude.. but I cant read that and don't even know what language it is.. is there a manual that you can link that is in English.. maybe someone can help once we understand what were looking at..
 
so I clicked the link.. not to be rude.. but I cant read that and don't even know what language it is.. is there a manual that you can link that is in English.. maybe someone can help once we understand what were looking at..
English option is in the upper right corner of the linked page.
 
Ye
so I clicked the link.. not to be rude.. but I cant read that and don't even know what language it is.. is there a manual that you can link that is in English.. maybe someone can help once we understand what were looking at..
Sorry. There is an icon on the top right corner to change to English. This is the exact model I own. I'm worried about 2 things. The distance between the baffle and the grills is at 34cm. And there are 2 glasses on each sides while there is another glass on the front. Isn't that an issue for secondary combustion? I read somewhere, someone said glasses are like heatsinks. I tried to look for fire bricks but unfortunately they are not big enough to cover my side windows. And replacing them with cast iron requires cast welding to be applied (said the manufacturer). Wish i knew the side glass was optional. I would got a full cast iron stove with only glass on the front.
 
So it can burn coal. That’s a hint. I didn’t see any manual do you have one? Basically you need to get a fire going then turn down the primary (bottom air) once the fire is hot. Do you have control of the secondary (top) air separate from the primary?

Coal is different it really need bottom air.
 
That's a sweet looking coal burner! All coal stoves can burn wood. Difference being as noted they will take draft from under the grate never above. They will not have any control for secondary burn save for any permanent baffling as part of the stove itself. For wood though my guess is burn times would be limited. For coal I could see 12 hour constant burn time there.
 
So it can burn coal. That’s a hint. I didn’t see any manual do you have one? Basically you need to get a fire going then turn down the primary (bottom air) once the fire is hot. Do you have control of the secondary (top) air separate from the primary?

Coal is different it really need bottom air.
Unfortunately no manual. There is the top air intake you can turn on or off above the front window part. On the back there is a small double walled part with 2 intake holes (3mm probably) and 10 intake in the firebox side. That's the only place where secondary burn could happen I guess.

The primary (bottom) and secondary (top) has different controls yes. I will redo the gaskets for side windows.

I guess we will see if it does do secondary burning this winter. Climate is very good right now house temp is around 23C and outside it's like 17C.

I put 4 pieces of 20x10x2 firebricks on corners to increase firebox operating temperature. I guess I will buy the side glass cast iron parts for the future. Because eventually there will be no parts left in production.. They said you need cast weld to install them. So i will keep my glasses.

I have seen people modding their cast iron stoves to add tubing with secondary intake.


Manufacturer say the top air intake is for air wash for front glass.
 
That's a sweet looking coal burner! All coal stoves can burn wood. Difference being as noted they will take draft from under the grate never above. They will not have any control for secondary burn save for any permanent baffling as part of the stove itself. For wood though my guess is burn times would be limited. For coal I could see 12 hour constant burn time there.
Actually they are sold as wood stoves there. I didn't know it burnt coal. People who burn coal usually buy bucked stoves made from metal. I am not feeling sure about burning coal in a 3 glass stove. Wish i knew I had the option for single glass when I was buying it.. Totally pointless to have side glasses. Also they have a side loading version that would be cool actually..
This is the same model with side loading + top cooking part (i heard that vertical cusine stoves don't cook as good as horizontal cooking stoves)
 
Not sure if it's been said above, but you could add brick to the bottom (floor) of the stove, to get the fire closer to the baffle. I'm not sure it's all going to work though.

What is the rated efficiency of this thing, or are no test data available?
 
Not sure if it's been said above, but you could add brick to the bottom (floor) of the stove, to get the fire closer to the baffle. I'm not sure it's all going to work though.

What is the rated efficiency of this thing, or are no test data available?
Unfortunately no test data. I wish we had the EPA similar forced regulations for stove manufacturers and importers (most are made in Turkey tho) exporters. This is completely made from cast iron. With a baffle that's all i know but manufacturer say the 2 vent hole on the back is for burning gases and smoke and sometimes (i only used this stove 12 times last March as that's when I bought it) I saw no smokes. And sometimes white color smoke (steam maybe?).

I wish I had to skills to add a giant perforated SS tubing to the baffle and take advantage of that height. I have no such skills lol. The only data posted is 9kw energy output. I don't think they test those. But once i saw some text like this for this stove :
CO2 ratio % 0,02 - % 0,04 dust concentration 30 mg / Nm³ Performance index 0,2 natural wood pelets length :30 mm diameter : 6 mm capacity of loading 22 Kg consumption 0,7 - 1,7 kg /hour
But I have no idea if this is actually accurate. How can I calculate hourly burn rate for per kilogram? I have a good wood moisture meter and a scale. I can scale the wood weight and set the time when it begins to burn until it becomes coals.? But I am sure real test is done with a scale carrying the whole system showing delta for each hour of burn.

I was getting like 3 to 4 hours of burn with this stove but I have to check it.
 
Many times we see stoves that the glass was broken and just replaced with a piece of flat steel that was about the same thickness as the glass and cut to the same dimensions. It would get installed using the same gasket material as the glass.

Take some pictures of the Inside. I would like to see how they designed it. And a picture of it burning. Video is even better.

generally speaking coal stoves are not good wood stoves. And wood stoves can’t burn coal so I am guessing there were some compromises.
 
Ok. I was asking about efficiency, because if it was good you would likely not benefit from adding tubes.

You mention pellets (6*30 mm)... I don't understand that, as there is no feeding mechanism. Of course you can buy pellets and burn them in a wiid stove, but that is rather cumbersome.

If the stove has a 9 kW rating it'll burn about 2 kg per hour (at THAT output rate!). So a 8-10 hr burn time should be possible. There are fudge factors here (efficiency, and assuming an optimal system, and maybe the 9 kW is on the low side of the output range, etc. etc. etc.).
 
They have thick cast iron parts for glass. But installing requires some welding :/ I will still buy the parts for feature. will post a link below. I will post a video next month when i burn this stove with dry oak. I will try the secondary burning thing too and I will check the flue smoke output (how visible etc).

No these are never sold as coal burners. They burn wood. Most buyers (almost all) only burn wood or wood briquettes made from saw dust (more expensive than wood but they claim 4 times more heat (i am not sure if it'd real) ) output. But the grill is not like usual grills. It's really really thick and they claim it's cast (grill part) using a different casting technique. It's not something you could damage by burning coal. There is no metal parts in that stove. There is also no fire bricks. But i installed some to increase firebox operating temperature to achieve secondary burns for this winter. (1 brick is 2 usd so why not trying lol). If I could get a good price for installation labor by a welder I could replace the glasses.

These videos are from April. I believe the wood wasn't properly seasoned by that time. Also my front glass didn't have a gasket.. The seller said it was okay. Of course it wasn't okay. I put an 8mm white gasket now. And I have some made in USA carbon impregnated flat gasket, i will apply them to the side glasses on both sides. Currently it's only 1 side. I also ordered some white 8mm gasket for baffle. I will also insulate the sides. There was some really seasoned wood, they didn't hiss or had steam on it. I have near 2 tones of dry wood in my terrace now. But it probably won't be enough for this season. I don't want to buy wood as they are 6 months old (not well seasoned) and they have so many bugs.. I'm even not super sure how i will take the woods that I will burn inside once winter hits. I am thinking of using my electric stove at 100C pre heat and bake them there to kill the friggin bugs. Would it catch on fire? Lol. I hate bugs.
I uploaded videos from last April



Many times we see stoves that the glass was broken and just replaced with a piece of flat steel that was about the same thickness as the glass and cut to the same dimensions. It would get installed using the same gasket material as the glass.

Take some pictures of the Inside. I would like to see how they designed it. And a picture of it burning. Video is even better.

generally speaking coal stoves are not good wood stoves. And wood stoves can’t burn coal so I am guessing there were some compromises.
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How about setting a piece of metal inside of the glass? It'll reflect the heat back into the stove,.

You can fill the coal grate with ash to eliminate air from coming up from the bottom. Then its down to keeping heat in the stove. Is there a baffle?
 
Ok. I was asking about efficiency, because if it was good you would likely not benefit from adding tubes.

You mention pellets (6*30 mm)... I don't understand that, as there is no feeding mechanism. Of course you can buy pellets and burn them in a wiid stove, but that is rather cumbersome.

If the stove has a 9 kW rating it'll burn about 2 kg per hour (at THAT output rate!). So a 8-10 hr burn time should be possible. There are fudge factors here (efficiency, and assuming an optimal system, and maybe the 9 kW is on the low side of the output range, etc. etc. etc.).
Yeah no idea about the consumption. 2k sounds bad right? The epa stoves consume 1kg so i heard. Its just crazy how well they must be running. The only good thing is I can burn coal if i run out of wood or briquettes etc. I added some firebricks to increase the internal temps. Let's see how it will go this winter. Should I load the stove fully to achieve a 10 hour burn time? It could over heat the stove lol
 
How about setting a piece of metal inside of the glass? It'll reflect the heat back into the stove,.

You can fill the coal grate with ash to eliminate air from coming up from the bottom. Then its down to keeping heat in the stove. Is there a baffle?
here is the video of my stove

Yes there is a baffle. Piece of metal inside of the stove to cover the glass? Sounds cool if i get it right.

I can turn off the main in takes. In this video you can see there is a vent mechanism for air wash intake.
For the main intake in pics you can see some valve like stuff I can turn rotate them to let them air in or i can close it or make it ajar etc.
 
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Yeah no idea about the consumption. 2k sounds bad right? The epa stoves consume 1kg so i heard. Its just crazy how well they must be running. The only good thing is I can burn coal if i run out of wood or briquettes etc. I added some firebricks to increase the internal temps. Let's see how it will go this winter. Should I load the stove fully to achieve a 10 hour burn time? It could over heat the stove lol
I did not do the calculation how many kgs my stove uses.
But you can't say "2 kg is bad" or "1 kg is good". Because a stove that puts out 90% of the energy in wood, and uses 2 kg of wood per hr is better (i.e. more efficient) than one that puts out 70% of the energy in the wood and uses 1 kg per hr. Or vice versa, one that uses 1 kg per hr at 90% efficiency is better than one that uses 2 kgs per hr at 70% efficiency. The 2 kg per hr stove just puts out MORE heat per hour.

What you need to look at (if you want to look at efficiency) is how much energy is in 2 kg of wood (5.25 kWh), and how much the stove puts out. I assumed an efficiency in my numbers above by simply rounding them (that should therefore only be taken within a large error margin).

Point is "kg per hour" is not bad or good. A big stove uses more kg per hr, but puts out more heat. It can do so efficiently (less heat up the flue) or less efficiently (more heat up the flue). The good/bad (efficiency) has nothing to do with the absolute number of kgs/hr.
 
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They have thick cast iron parts for glass. But installing requires some welding :/ I will still buy the parts for feature. will post a link below. I will post a video next month when i burn this stove with dry oak. I will try the secondary burning thing too and I will check the flue smoke output (how visible etc).

No these are never sold as coal burners. They burn wood. Most buyers (almost all) only burn wood or wood briquettes made from saw dust (more expensive than wood but they claim 4 times more heat (i am not sure if it'd real) ) output. But the grill is not like usual grills. It's really really thick and they claim it's cast (grill part) using a different casting technique. It's not something you could damage by burning coal. There is no metal parts in that stove. There is also no fire bricks. But i installed some to increase firebox operating temperature to achieve secondary burns for this winter. (1 brick is 2 usd so why not trying lol). If I could get a good price for installation labor by a welder I could replace the glasses.

These videos are from April. I believe the wood wasn't properly seasoned by that time. Also my front glass didn't have a gasket.. The seller said it was okay. Of course it wasn't okay. I put an 8mm white gasket now. And I have some made in USA carbon impregnated flat gasket, i will apply them to the side glasses on both sides. Currently it's only 1 side. I also ordered some white 8mm gasket for baffle. I will also insulate the sides. There was some really seasoned wood, they didn't hiss or had steam on it. I have near 2 tones of dry wood in my terrace now. But it probably won't be enough for this season. I don't want to buy wood as they are 6 months old (not well seasoned) and they have so many bugs.. I'm even not super sure how i will take the woods that I will burn inside once winter hits. I am thinking of using my electric stove at 100C pre heat and bake them there to kill the friggin bugs. Would it catch on fire? Lol. I hate bugs.
I uploaded videos from last April




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I like the idea of the bricks in the corners and if all they do is keep the wood off the side glass great. Fill it full of wood. When I reload I fill to almost touching the top. I light a top down fire.

Looking at the pictures it is not going to have secondary combustion like a stove with secondary burn tubes at the top. If it keep you warm I’d say it’s good enough. Changing an approved design to make it better I think is difficult.
 
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I like the idea of the bricks in the corners and if all they do is keep the wood off the side glass great. Fill it full of wood. When I reload I fill to almost touching the top. I light a top down fire.

Looking at the pictures it is not going to have secondary combustion like a stove with secondary burn tubes at the top. If it keep you warm I’d say it’s good enough. Changing an approved design to make it better I think is difficult.
I added the fire bricks to prevent cracks on the corners (no idea how likely that is tho) and to have more heat radiate when wood is all burnt. Also to increase the efficiency if that makes sense (I have no idea lol).
 
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Should I load the stove fully to achieve a 10 hour burn time? It could over heat the stove lol
Yes, more splits per load until you are comfortable with a complete load. Load all splits straight in or what is referred to as north/south loading. See what kind of results you get at each level of loading. Unless your draft makes the burn uncontrollable you should not have to worry about overheating.

Almost seems to me that the 2 lower air control knobs may be for coal burning primarily as they introduce air under the load?

Believe I'd try a few different approaches to burning until I found a good repeatable method.

Maybe try supplying all primary air with the upper slide control only (2 lower front knobs closed). This would replicate wood burning stoves that I am used to. Appears as if there may be regulated or unregulated secondary air supply entering the back of the firebox through the series of small holes as well.

No idea what the hearth insulation requirements are for this model? I would surely think more ember protection in front would be appropriate.
Just some random thoughts. Good luck.
 
Yes, more splits per load until you are comfortable with a complete load. Load all splits straight in or what is referred to as north/south loading. See what kind of results you get at each level of loading. Unless your draft makes the burn uncontrollable you should not have to worry about overheating.

Almost seems to me that the 2 lower air control knobs may be for coal burning primarily as they introduce air under the load?

Believe I'd try a few different approaches to burning until I found a good repeatable method.

Maybe try supplying all primary air with the upper slide control only (2 lower front knobs closed). This would replicate wood burning stoves that I am used to. Appears as if there may be regulated or unregulated secondary air supply entering the back of the firebox through the series of small holes as well.

No idea what the hearth insulation requirements are for this model? I would surely think more ember protection in front would be appropriate.
Just some random thoughts. Good luck.
Thanks for the tip. I should try to load as you said the cigarette orientation (and lighting from top to bottom). I will first probably open those vents on below when the fire goes nice like 10 mins i will turn them off as there will be good draft. And open the airwash slider and see how long it burns without smouldering. Actually that's very smart, it could definitely give a secondary burn. I was previously afraid of overheating the stove because i remember the top part was feeling soft when I was burning wood. (maybe it was curing no idea but iron should stand those temps well to my knowledge)

Well almost most cast wood stoves made here uses the ground feeding. And people very rarely burn coal with those. But i now I understand it better. The wood wood stove design isn't oxygen fed in the grates but top side right? The back side ventilation is always working can't close it it's like a double walled structure where 2 holes intakes air from exterior side, and it gets hot in between the 2 walls and then it's fed into stove from 10 holes. It's not direct holes, so it moves in that a bit.




For heart insulation if i understand correctly, that's my reply :There is an Ash pan under the grate. And below its cast iron. Under the wood stove you can even touch, it somehow doesn't get how in the buttom.

The sellers and manufacturers say the 2 lower control is for the wood burning but they are for cast iron stoves. The metal makers don't have those intake vents. So you may be right. They may be designing those with coal burning on head and then marketing for them for wood burners because then why would it have an air wash intake? I even saw a seller claiming the top intake is for initial burn to happen quickly :) he has no idea...

For example these guys make metal models with secondary burners. I believe there is no language setting but Google translate would do the job.
 
Yeah so little update.

I did insulate the baffle fully. I did insulate the grate and some edges inside the stove.
I used a 8 percent humidity 2 year old oak. It stated to burn very fast ;D

It burns very clear. I turned off main intakes. Just the airwash and back vent holes.
Yeah the stove has seen 270~ Cs. 550F~ and you can see the back vent hole burts probably some secondary burns.



 
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