# Another 1980 Knock-off  and secondary burn



## Blazzinghot (Dec 9, 2019)

Hi I have been reading all about knock-offs and the old Defiant stoves on this forum. But still have a question but let me first introduce you to my duplicate.
I just wanted to add my knock-off to the collection. I am not wanting to identify it as the stove name is still on the label but can't read all of it. It was tested in 1980 by the PFS Cooperation which at this time was in Madison, Wisconsin. It is from the Taiwan Fita Industry and it has a 7-inch oval flue on the top. It does not have the slight orange peel look on the surface or what some of you called modeled look. The casting is different from the Olympic Crest and the Scandia 315. It has a rectangular square casting on the sides and off course it is the same size as the Defiant and very close to the older models. It does not have bricks on the back wall but there are bricks on the bottom. It also has writing on both the top front of the stove and above the side door which something I have not seen in the other knock-offs. The man I spoke with at EPA said he was surprised to see my stove was tested. I realize that the test may not be the standard for today but it did past the testing in 1980.
I have contacted Vermont Castings and they sent me the manual for the 1975 model Defiant. I also am aware of how some here feel about these knock-offs as I have read most of the threads on these stoves on this forum. I have to much invested in this stove to be discouraged about it. Please try to be as upbeat as possible with me.  I did not see the Taiwan stamp on the back until I had it all taken apart so I have given this stove a face lift.
I have made a whole new damper with ¼ steel and better rod for turning it. Then I bolted ¼ inch steel plate to the interior wall as it was starting to crack. I had to do some fancy slicing and bending to match the curve shape. Then re-drill the holes in the bottom 1/4  plating of the inner wall were the holes were in the cast iron.
In the pictures you will see my fancy silver acorn bolts on the doors.  I had to drill through the doors as the bolts were broke off I did drill them out but the tap for threading was tapered and the holes were not deep enough to make it work so I drilled out the doors and put on these fancy acorn nuts to fasten in the new ceramic glass windows.
But here is my question. I have read on this forum about people have trouble getting the secondary burn to work but I have not really found what a secondary burn should look like. In my own mind I have an idea but it could be a misconception. I have never had stove before with a horizontal burn.  I don’t have a heat gauge. I do get a hot bed of coals in the stove and then close the damper. I do get a nice red glowing coals with very little flame until the logs burn down. The coals seem to be burning from the bottom up.  There is no smoke coming from the outside stove pipe. I have two 90 degree turns in the stove pipe which is about 15 feet from the stove to the top. I have reduced the pipe from seven to six inch. It seems like I am getting a secondary burn but I don’t see anything going into the secondary burn chamber. You might ask about the bi-metal thermostat? I keep it wide open until I get things going and then close it half way after when I move the damper in the up position. But I am still in the process of making a box for the thermostat after reading the comments on this forum. I have also experimented with the keyhole air intake on the end and find it works better if I leave it open.
I made this long because I have noticed what questions you ask so I tried to cover them all in this post.
How does a person know if the secondary burn is working?


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## fbelec (Dec 10, 2019)

where is your key hole air intake? is it on the left side like a defiant? it sure looks like a defiant


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## bholler (Dec 10, 2019)

Blazzinghot said:


> Hi I have been reading all about knock-offs and the old Defiant stoves on this forum. But still have a question but let me first introduce you to my duplicate.
> I just wanted to add my knock-off to the collection. I am not wanting to identify it as the stove name is still on the label but can't read all of it. It was tested in 1980 by the PFS Cooperation which at this time was in Madison, Wisconsin. It is from the Taiwan Fita Industry and it has a 7-inch oval flue on the top. It does not have the slight orange peel look on the surface or what some of you called modeled look. The casting is different from the Olympic Crest and the Scandia 315. It has a rectangular square casting on the sides and off course it is the same size as the Defiant and very close to the older models. It does not have bricks on the back wall but there are bricks on the bottom. It also has writing on both the top front of the stove and above the side door which something I have not seen in the other knock-offs. The man I spoke with at EPA said he was surprised to see my stove was tested. I realize that the test may not be the standard for today but it did past the testing in 1980.
> I have contacted Vermont Castings and they sent me the manual for the 1975 model Defiant. I also am aware of how some here feel about these knock-offs as I have read most of the threads on these stoves on this forum. I have to much invested in this stove to be discouraged about it. Please try to be as upbeat as possible with me.  I did not see the Taiwan stamp on the back until I had it all taken apart so I have given this stove a face lift.
> I have made a whole new damper with ¼ steel and better rod for turning it. Then I bolted ¼ inch steel plate to the interior wall as it was starting to crack. I had to do some fancy slicing and bending to match the curve shape. Then re-drill the holes in the bottom 1/4  plating of the inner wall were the holes were in the cast iron.
> ...


Is it EPA tested or is it just tested to ul standards?


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## Blazzinghot (Dec 10, 2019)

where is your key hole air intake? is it on the left side like a defiant? it sure looks like a defiant
[/QUOTE]

The key hole is on the left side. And I agree that this stove looks allot like a Defiant. I posted this stove because I can't find anything to match it on the internet. There are some that are close but they have what is called the light orange peel texture and this stove is smooth.  And this stove has windows. I have not found a knock-off with windows like this one.  The other reason I posted is I am not sure what to look for in a secondary burn. Nothing much is happening in the secondary burn camper but I am getting a nice bed of coals with some flame on the left side of the stove. The coals burn nice and hot and give me an even heat.


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## Blazzinghot (Dec 10, 2019)

bholler said:


> Is it EPA tested or is it just tested to ul standards?


I am not sure if EPA  tested stoves in 1980? From what I have read the official EPA ratings started in 1988 but I am not an expert on this topic so am sure someone will address this issue. But it was UL tested and given a rating of .737 which I still need to check out. I talked with PFS and they could not offer any info on this wood stove. It appeared that they did not keep records for 1980.  This wood stove  has a I. C. B. O. Research Number 8801 which I don't understand.. There is other print on the bottom of the tag on the stove which I can't make out. I took a picture of the tag and then put it in my Photo program and adjusted the contrast which helped me to read some of it. 

I mentioned the EPA because someone suggested calling them to see if they have info on this stove. The man was very friendly and we exchange several emails as I was curious bout the new ruling that is coming out in May of next year for the new EPA standards. He sent me a list of all the stoves that are already compliant with the new emissions standard and yes Vermont Casting is already ahead of the game.


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## bholler (Dec 10, 2019)

Blazzinghot said:


> I am not sure if EPA  tested stoves in 1980? From what I have read the official EPA ratings started in 1988 but I am not an expert on this topic so am sure someone will address this issue. But it was UL tested and given a rating of .737 which I still need to check out. I talked with PFS and they could not offer any info on this wood stove. It appeared that they did not keep records for 1980.  This wood stove  has a I. C. B. O. Research Number 8801 which I don't understand.. There is other print on the bottom of the tag on the stove which I can't make out. I took a picture of the tag and then put it in my Photo program and adjusted the contrast which helped me to read some of it.
> 
> I mentioned the EPA because someone suggested calling them to see if they have info on this stove. The man was very friendly and we exchange several emails as I was curious bout the new ruling that is coming out in May of next year for the new EPA standards. He sent me a list of all the stoves that are already compliant with the new emissions standard and yes Vermont Casting is already ahead of the game.


Yes Vermont castings has some 2020 compliant stoves.  But they still have many of the same problems their stoves have had for years.  They are slowly getting better but have a long way to go to catch up with most of the industry as far as reliability and ease of use.  Hell one of their new stoves is a fixed burn rate stove with no control.  They haven't been ahead of the game for a long time.


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## peakbagger (Dec 10, 2019)

I  expect it would be difficult to figure out if the secondaries are actually working unless someone wanted to use an extractive probe to pull a sample of the gases leaving the firebox and then leaving the secondary chamber.  CO is the usual pollutant that can escape the primary burn chamber although along for the ride are condensable liquids if the wood is wet. These liquids are mixed with water and they usually are not concentrated enough to burn if burning wet wood as there is too much water vapor around. If they are not burned they will go out into the stack and condense on the walls eventually forming creosote as the solids build up and water vapor goes up the stack. If the wood is dry they rapidly dry out enough to burn.

In order to burn CO the temp needs to exceed 1100 degrees unless there is a catalyst involved. There has to be adequate oxygen and the sufficient turbulence to get the O2 molecules in contact with the CO.  Usually the molecules eventually get together if there is enough residence time in the flame path if its long enough, but the problem is heat is being radiated from the exhaust plume so at some point the temp drops below 1100 F.  As you noticed  the primary fire burns from the bottom up once the bypass lever is engaged as the air on a Defiant is introduced through the cast runners located just below the side door and along the fireback. The exit to the secondary chamber is down low and much smaller than the firebox so the gas molecules have to cram together close to each other to fit through the smaller opening. Its acting like a orifice and that means a lot more turbulence.  Once the gases make it through the opening they expand rapidly introducing more turbulence and are immediate  exposed to the secondary air that in theory has been conducted there by the partially cast and refractory tunnel running along the back of the fireback.  This is the logical point of secondary burn as once the gases expand into the chamber off to the side of the primary firebox there is lot of external surface area for the exhaust to cool down below 1100 F. From there on there really is no combustion going on, but there is heat transfer and that is where the Defiant design excelled, in addition to the chamber on the right, gases go behind the fireback and are exposed to another large area of outer wall (the back of the stove) before exiting.

Of course if the wood was wet and the bypass was not engaged it reverted to a inefficient smoke dragon with slightly better air control.


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## Blazzinghot (Dec 10, 2019)

bholler said:


> Yes Vermont castings has some 2020 compliant stoves.  But they still have many of the same problems their stoves have had for years.  They are slowly getting better but have a long way to go to catch up with most of the industry as far as reliability and ease of use.  Hell one of their new stoves is a fixed burn rate stove with no control.  They haven't been ahead of the game for a long time.



I am not real familiar with the Vermont Castings but have taken an interest since I found this duplicate. I am glad they are improving them. I was surprised from the list of stoves that some had their emissions down to 1.5 or less. Stoves have come along ways since the 80's. Thanks for you comments.


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## Blazzinghot (Dec 10, 2019)

peakbagger said:


> I  expect it would be difficult to figure out if the secondaries are actually working unless someone wanted to use an extractive probe to pull a sample of the gases leaving the firebox and then leaving the secondary chamber.  CO is the usual pollutant that can escape the primary burn chamber although along for the ride are condensable liquids if the wood is wet. These liquids are mixed with water and they usually are not concentrated enough to burn if burning wet wood as there is too much water vapor around. If they are not burned they will go out into the stack and condense on the walls eventually forming creosote as the solids build up and water vapor goes up the stack. If the wood is dry they rapidly dry out enough to burn.
> 
> In order to burn CO the temp needs to exceed 1100 degrees unless there is a catalyst involved. There has to be adequate oxygen and the sufficient turbulence to get the O2 molecules in contact with the CO.  Usually the molecules eventually get together if there is enough residence time in the flame path if its long enough, but the problem is heat is being radiated from the exhaust plume so at some point the temp drops below 1100 F.  As you noticed  the primary fire burns from the bottom up once the bypass lever is engaged as the air on a Defiant is introduced through the cast runners located just below the side door and along the fireback. The exit to the secondary chamber is down low and much smaller than the firebox so the gas molecules have to cram together close to each other to fit through the smaller opening. Its acting like a orifice and that means a lot more turbulence.  Once the gases make it through the opening they expand rapidly introducing more turbulence and are immediate  exposed to the secondary air that in theory has been conducted there by the partially cast and refractory tunnel running along the back of the fireback.  This is the logical point of secondary burn as once the gases expand into the chamber off to the side of the primary firebox there is lot of external surface area for the exhaust to cool down below 1100 F. From there on there really is no combustion going on, but there is heat transfer and that is where the Defiant design excelled, in addition to the chamber on the right, gases go behind the fireback and are exposed to another large area of outer wall (the back of the stove) before exiting.
> 
> Of course if the wood was wet and the bypass was not engaged and it reverted to inefficient smoke dragon with slightly better air control.



This is a very detailed description of the secondary burn process which does help me to realize how complicated it could be to know if I am getting a secondary burn. I am sure it could be more complex pending on which wood I am burning and how much moisture is in the wood along with other factors such as leaky stove. I can only tell  you what I know from observation. The second time I lite a fire in this stove and had it the damper up there were some nice dancing blue flames which were turning like small  slow tornadoes.  Very enjoyable to watch. Then there are some blue flames that are pulled to the secondary chamber but they disappear before they enter.  

I watched a video were a man drilled a hole in the side of the stove similar to mine (Defiant?)  so he could see what was going on inside.  There were allot of yellow flames being sucked through the secondary camber and you could see them following the path around the wall up to the vent. The stove I have does not have any visible flames being sucked into the this camber.  But doing comparisons are not always accurate. Are you supposed to see the flames being sucked into the secondary chamber or should I not be concerned about it? 

Thanks for responding to my post.


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## peakbagger (Dec 10, 2019)

I dont have any newer technology stoves or boilers so will need to have others chime in on secondary flames. I know when I am messing with really big biomass power boilers if the grate is burning with inadequate air,  the flames are a decidedly  dull yellow, put in too much air and burn too hot and it is bright white. I cant remember seeing blue flames but boilers like that are much different beasts than wood stoves.

I really would not worry about it. If there is enough draft for bypass and the woods not too wet and hissing the best efficiency is in bypass. A efficient stove is inherently a clean stove at the temps we are talking about.


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## Blazzinghot (Dec 11, 2019)

Thanks for the replies but I am hoping some of you who have horizontal burn stove similar to the Defiant can tell me what you observe when your stove is in secondary burn mode. I am sure pending on the wood dry wet hard or soft that is may burn somewhat different but there still may be some commonalities  from observation. It would at least be interesting to discuss.  I have been burning some scrap 2 X 4 pine to get the fire going then I have some three year old fruit tree logs (don't know what kind) and Black Locust logs from trimming my tree two years ago that I put on top of the coals.   Here are some pictures of this stove set up in my shop for those of you who want to get a closer look at it.


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## begreen (Dec 11, 2019)

Rear clearance does not look right. What is the stuff behind the stove? Is there drywall behind that?


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## Blazzinghot (Dec 11, 2019)

begreen said:


> Rear clearance does not look right. What is the stuff behind the stove? Is there drywall behind that?


Thanks for looking at my pictures. I was wondering if someone was going to comment on my plastic Lowes bucket being so close to the stove. Behind this stove is cement hardypanel and behind this is a large piece of corigated sheet metal screwed to the wall on 1/2 sheet rock.  And a small scrap piece of sheet rock behind the hardypanel. I usually have my old Earth Stove here but I needed to test this stove in the picture before I sell it.


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## fbelec (Dec 13, 2019)

in a defiant stove to see the secondary the stove has to be hot for 45 minutes to a hour. above 600 does it. open the key hole vent on the left side and look in to the far right side. then flip the damper over to make the smoke go horizontal then look thru the hole again if there is no secondary flame you'll see nothing if there is a secondary flame you will see the light from the flame. i've had yellow white to slightly blue color.


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## Blazzinghot (Dec 13, 2019)

fbelec said:


> in a defiant stove to see the secondary the stove has to be hot for 45 minutes to a hour. above 600 does it. open the key hole vent on the left side and look in to the far right side. then flip the damper over to make the smoke go horizontal then look thru the hole again if there is no secondary flame you'll see nothing if there is a secondary flame you will see the light from the flame. i've had yellow white to slightly blue color.



Thanks for you taking the time to check your secondary burn. I just fired up the stove today with pine. We have a lumber yard here in town and I just got a trailer load  of 2 x 6 end pieces for a good price. I don't have a heat gauge on my stove but I got it Blazzinghot then I closed the damper and waited awhile and checked the key hole but saw nothing but dark. This clone my be different from yours. When I had it all apart the back cast iron wall has a channel that runs the length of it on the inside about in the middle of the wall. And the inside wall also has a similar channel and when I put the stove together the two channels meet together. There is a gap for expansion and contraction. But this channel forms the air channel that goes into the secondary chamber. Then because I did not like the gap on the top I places a 1/4 x 3/4 length of metal strapping over the gap. The keyhole air intake is below this channel and the fire goes above the channel.  But from the pictures through the glass I can see that I am getting a very good burn on the coals with very little flame. And I was happy to see what little flames I  had pulling towards the secondary chamber by looking  through the glass. I am happy with the way it is burning with a good set of red hot  coals low flame and no smoke coming out the end cap. It burns slow, steady and hot and is not eating the wood too fast. Had the air intake most of the way closed with the keyhole 3/4 open.

The one picture that looks like eyes you can see the flames pulling towards the secondary chamber. And I can see those set of eyes looking at me seem foreboding.  The flame is a tad on the orange side because of glass is not clean but this is what is going on in the secondary burn.


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## bholler (Dec 13, 2019)

Blazzinghot said:


> Thanks for looking at my pictures. I was wondering if someone was going to comment on my plastic Lowes bucket being so close to the stove. Behind this stove is cement hardypanel and behind this is a large piece of corigated sheet metal screwed to the wall on 1/2 sheet rock.  And a small scrap piece of sheet rock behind the hardypanel. I usually have my old Earth Stove here but I needed to test this stove in the picture before I sell it.


I am just curious how much you are going to try to sell it for


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## Blazzinghot (Dec 13, 2019)

bholler said:


> I am just curious how much you are going to try to sell it for


 I am thinking about $350.00 but not sure I have bout  $200.00 into it will metal plating, glass and new gaskets and paint. My labor does not count because it was a learning experience and I enjoyed watching it transform before my eyes.   I might sell the Earth Stove instead because I like the looks of this clone.


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## bholler (Dec 13, 2019)

Blazzinghot said:


> I am thinking about $350.00 but not sure I have bout  $200.00 into it will metal plating, glass and new gaskets and paint. My labor does not count because it was a learning experience and I enjoyed watching it transform before my eyes.   I might sell the Earth Stove instead because I like the looks of this clone.


The Earth stove is a better stove.  I think the clone might be worth 250 if you are lucky


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## fbelec (Dec 16, 2019)

that channel should have a piece of screen shaped like a v and then covered in furnace cement. it supposed to be separated from the main air that's probably why you don't see a secondary flame. that path brings over fresh air to the secondary manifold for reburn. you need a stove top thermometer you don't want to run her to hot and ruin the fresh paint at minimum.


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## Blazzinghot (Dec 16, 2019)

fbelec said:


> that channel should have a piece of screen shaped like a v and then covered in furnace cement. it supposed to be separated from the main air that's probably why you don't see a secondary flame. that path brings over fresh air to the secondary manifold for reburn. you need a stove top thermometer you don't want to run her to hot and ruin the fresh paint at minimum.


Thanks for your comments. I am not picturing what you are explaining. I am going to look at my 1975 Defiant manual and see if I can find this V shaped screen in the parts list. If it has one. I want to get this working. This is why I am asking what a secondary burn looks like with this stove. It sounds like it is built very similar to the old Vermont Models.


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## fbelec (Dec 17, 2019)

i also forgot to say that if it is true that your stove is a copy of the defiant that you should build your fire up against the right side of the stove up against the baffle. (the plate that divides the main fire from the secondary chamber) doing this makes the baffle as hot as it can get and helps with the flame from the main fire go into the secondary chamber for the light off of the secondary fire.


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## fbelec (Dec 17, 2019)

incase you don't have this. this should cover the rebuild of a defiant


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## Blazzinghot (Dec 17, 2019)

fbelec said:


> incase you don't have this. this should cover the rebuild of a defiant


Thanks this is more detailed than the manual I have. I have to agree with someone on this forum stated this was a poor design on this stove. This looks like quite an ordeal putting in this cement and getting it all together. I wished I would have had this picture when I put this stove together. I used clamps and the casket cement starts to dry up before you can pull all things together  I barley made it. I was thinking of putting a piece of square rectangular tubing in this slot with some small casket rope on both sides to seal it.  Yes I know I am trying to think outside the box. Yes I will loose some space but will have a air tight chamber. Any thoughts? And yes from this pictures in this manual  my stove is just like this one.


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## peakbagger (Dec 17, 2019)

I agree that secondary air tube is a PITA to get sealed and not one of their better ideas. I expect cement eventually cracks no matter how well its done. Your concept may work as well. The alternative is run sch pipe along the back of the firebox and skip the channel. it would need supporting but would get hotter than the original setup. Hot secondary air is good as in it doesn't reduce the flame temp as much.


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## Jerry Leighton (Jan 3, 2022)

Blazzinghot said:


> Hi I have been reading all about knock-offs and the old Defiant stoves on this forum. But still have a question but let me first introduce you to my duplicate.
> I just wanted to add my knock-off to the collection. I am not wanting to identify it as the stove name is still on the label but can't read all of it. It was tested in 1980 by the PFS Cooperation which at this time was in Madison, Wisconsin. It is from the Taiwan Fita Industry and it has a 7-inch oval flue on the top. It does not have the slight orange peel look on the surface or what some of you called modeled look. The casting is different from the Olympic Crest and the Scandia 315. It has a rectangular square casting on the sides and off course it is the same size as the Defiant and very close to the older models. It does not have bricks on the back wall but there are bricks on the bottom. It also has writing on both the top front of the stove and above the side door which something I have not seen in the other knock-offs. The man I spoke with at EPA said he was surprised to see my stove was tested. I realize that the test may not be the standard for today but it did past the testing in 1980.
> I have contacted Vermont Castings and they sent me the manual for the 1975 model Defiant. I also am aware of how some here feel about these knock-offs as I have read most of the threads on these stoves on this forum. I have to much invested in this stove to be discouraged about it. Please try to be as upbeat as possible with me.  I did not see the Taiwan stamp on the back until I had it all taken apart so I have given this stove a face lift.
> I have made a whole new damper with ¼ steel and better rod for turning it. Then I bolted ¼ inch steel plate to the interior wall as it was starting to crack. I had to do some fancy slicing and bending to match the curve shape. Then re-drill the holes in the bottom 1/4  plating of the inner wall were the holes were in the cast iron.
> ...


Hello, I have a Crescent Stove 1979/1980 vintage.  It appears to be a knock off similar to the Vermont castings and Olympic crest models.  I was wondering it anyone knows where I could get a new spark screen for this stove.  Thanks so much,
-Jerry


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## Blazzinghot (Jan 3, 2022)

Jerry,  Do a search under "Vermont Castings screens wood stoves" as many different sizes will appear. You might find something close enough to fit yours.


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