Superjack does not have secondary burn (well part of the time) - help me fix it

[mike1234]

After defending this furnace for the last year or so, I finally figured out that there is only a secondary burn when the draft inducer blower is on. I can open the door when the blower is on, and see secondary flames, not great ones like on some videos, but good ones. But on idle, no secondary burn. Keith can and maybe will disagree with this, but put a glass door on one and show it to me in a video Keith, then I will believe it.

So I think this is pretty easy to fix - the stove is made like a tank, I think it will last 20 or 30 years, and I would like to update it to a secondary burn and use less wood, and have less smoke. I've tried to attach a pics, too big I think, I'll fix tomorrow. You can see the specs of the furnace on www.yukon-eagle.com.

The front door brings air in during idle, so I propose to take that air and let some through to the wood for normal idling, and take the rest up to the top for secondary combustion. This requires a square piece of steal in front of the holes on the front door (this is at the bottom of the loading area, so I will be using 2 inches of that area). From this new channel, a few holes are drilled on the backside to let air into fire, on each end of that channel steal pipe goes up and to the back of the burn chamber to let the rest of the air out for the secondary burn. It would be superheated, it goes down through the front door (250 degrees or so) then in the chamber, so it will be hot.

If you are with me, (and I will post some poor design pics tomorrow) a couple of questions: 1. Sound good? or is this just dumb? 2. Will there be enough air for a secondary burn without some type of fan pushing the air?

I'll probably get it ready to go, have things drilled and welded and ready to install if we get a warm weekend, but maybe it will have to wait until march.

 

[Gooserider]

I will leave it to Keith to express his opinions on the mod itself, but I'd point out that any kind of mod like this will probably void any UL, etc., listings on the stove, void your warranty, and possibly cause your first-born child to get warts... :bug: Your call...

Gooserider

 

[lexybird]

im not sure if you would adequatly preheat the incoming air by just going through the front like that and then controling the air would be another matter in itself ,theres actually alot of thought and design that goes into a
epa stove with secondary burn technology.If i paid several thousands for a new stove/furnace and its under warranty i would not alter it or do anything that could possibly make it worse or worth much less ..butt hats just me .

 

[mike1234]

As far as the air control, the air through the door has a control on it, can turn it out or in to allow more or less air in.
As far as messing with the stove, if this did not work, I am not putting any new holes in the steal, all the add on's are on the inside, if I decided it was horrible, the most I would have to do is cut out the square bar in the front, I could even leave the tubes in, they would just be against the top, not in the way.
I agree it messes with the warranty, but like I said, it is built like a tank, it's not going to fail from workmanship.

My issue here is that although it has a secondary burn when the inducer fan is on, it is not a great secondary burn like I see on the videos - I think it could be much better. And it annoys me that it has no secondary burn when idling. So especially at night when I load it up and turn it down, all that unburned smoke is going to waste. During the day, smaller loads, fan runs most of the time, so not a big issue.

I guess I am not saying I have to do this, and it's too cold to shut it down for any period of time now, but if I can make an improvement, less wood to cut!
(broken link removed to http://picasaweb.google.com/Michael.Birney/Stihl290?feat=directlink) the 2 drawings and the last 4 are the ones of the furnace

im not sure if you would adequatly preheat the incoming air by just going through the front like that and then controling the air would be another matter in itself ,theres actually alot of thought and design that goes into a
epa stove with secondary burn technology.If i paid several thousands for a new stove/furnace and its under warranty i would not alter it or do anything that could possibly make it worse or worth much less ..butt hats just me .

 

[webbie]

To my knowledge that furnace was designed decades ago and Yukon purchased the designs from the original company. In general, that would preclude it being up to any current "clean burn" standards - such as the EPA furnaces. Realistically, no amount of modifications is going to help - if it was so easy, Yukon themselves would have done it.

I think you are on the right track with your making certain the furnace runs with the fan - smaller loads and shorter burns when you are in attendance.

 

[freeburn]

After defending this furnace for the last year or so, I finally figured out that there is only a secondary burn when the draft inducer blower is on. I can open the door when the blower is on, and see secondary flames, not great ones like on some videos, but good ones. But on idle, no secondary burn. Keith can and maybe will disagree with this, but put a glass door on one and show it to me in a video Keith, then I will believe it.

So I think this is pretty easy to fix - the stove is made like a tank, I think it will last 20 or 30 years, and I would like to update it to a secondary burn and use less wood, and have less smoke. I've tried to attach a pics, too big I think, I'll fix tomorrow. You can see the specs of the furnace on www.yukon-eagle.com.

The front door brings air in during idle, so I propose to take that air and let some through to the wood for normal idling, and take the rest up to the top for secondary combustion. This requires a square piece of steal in front of the holes on the front door (this is at the bottom of the loading area, so I will be using 2 inches of that area). From this new channel, a few holes are drilled on the backside to let air into fire, on each end of that channel steal pipe goes up and to the back of the burn chamber to let the rest of the air out for the secondary burn. It would be superheated, it goes down through the front door (250 degrees or so) then in the chamber, so it will be hot.

If you are with me, (and I will post some poor design pics tomorrow) a couple of questions: 1. Sound good? or is this just dumb? 2. Will there be enough air for a secondary burn without some type of fan pushing the air?

I'll probably get it ready to go, have things drilled and welded and ready to install if we get a warm weekend, but maybe it will have to wait until march.

While it's good idea, I don't think you'll get enough air in through the door only. I'm not exactly sure how large the hole is, but if it's just the slide draft, that's not near enough. One other thing, in order to get secondary burn, you have to have your whole firebox hot enough inside to allow those gases to "reburn". If not, it just cools down the firebox. There is a science to this, that's why the EPA stoves have firebrick top, sides and even bottom. I would leave well enough alone.

One other thing, when you open your door, the secondary air is going to stop immediately and go through the door, so you will not see the secondary burn at all ever with no window in the door (as you stated). The best way to judge that is by what's coming out your chimney.

If you want secondary burn, you need to get your entire firebox up to temp 400-500 deg with dry wood. Then shut off your draft fan and let it suck through the secondary air tubes on the side of the chamber. Try to find a way to block all other ways of air coming in except for the burn tubes on the side. That's the only way I see this working. Unless there is something else I'm not seeing. . .which according to my wife happens quite often. I would sure help if you put some actual pics up of your furnace and where you want it to go. I've never seen the inside of one of those things anyway. Just the less than descriptive drawings in the manual.

 

[DaveBP]

Mike, I don't know of any of the fancy forced-draft European or domestic gassifiers with refractory afterburner chambers that will sustain secondary combustion without the draft fan on. Maybe some cases with exception chimneys can but it's not part of their design. You want to see the rocket, you have to turn on the fan.

Idling just sucks, but sometimes under some conditions you have to live with it.

Or figure out a way to store the heat from a real secondary burn if the house can't use it at the moment.

 

[mike1234]

I was thinking 2ndary burns more like a wood stove, which when shut down for the night have nice 2ndary burns, and usually (always?) without a forced air fan. How about the hotblast 1950 (which is what made me start to think this was possible), it's it's 2ndary burn accomplished by forced air or just draft?

I also think that just because yukon hasn't done it doesn't mean it would not be easy to do. They have their furnace, it sells well, it does work well, maybe it's not 2009 technology, but they can say it has a secondary burn, why spend money updating that when they can work on X or Y?

Keep the ideas and questions coming, at the very least, even if I get talked out of it, it's a good discussion to have, and probably applies to some older wood stove owners also.

Mike, I don't know of any of the fancy forced-draft European or domestic gassifiers with refractory afterburner chambers that will sustain secondary combustion without the draft fan on. Maybe some cases with exception chimneys can but it's not part of their design. You want to see the rocket, you have to turn on the fan.

Idling just sucks, but sometimes under some conditions you have to live with it.

Or figure out a way to store the heat from a real secondary burn if the house can't use it at the moment.

 

[freeburn]

Caddy or 1950 has separate tubes that run the depth of the stove underneath the door on both sides, up the back (inside the firebox) and over the top (with reburn tubes). The air is superheated that way. The air is also completely separate from the primary air, so one can be completely shut down while the other, secondary takes over once the firebox is hot enough. In theory, 1950 (Caddy) is basically stove technology in a furnace, which I'm not sure why more aren't doing considering the EPA cert and the tax incentives, but I suppose if you can get your furnace to comply without changing the design, go for it.

 

[mike1234]

There is no problem with the temp of the fire and fire chamber, my thermostat above the door reads 500 all the time. The caddy's secondary air is not fan fed, just 2 tubes.

Finally, with all of your input, I think I can ask the right question: Why can't the yukon be that same stove technology in a furnace. It's not that far away, with the exception of the secondary burn tubes (I think). Please tell me how dumb that is, or tell me that I might be right, it's worth exploring.

Caddy or 1950 has separate tubes that run the depth of the stove underneath the door on both sides, up the back (inside the firebox) and over the top (with reburn tubes). The air is superheated that way. The air is also completely separate from the primary air, so one can be completely shut down while the other, secondary takes over once the firebox is hot enough. In theory, 1950 (Caddy) is basically stove technology in a furnace, which I'm not sure why more aren't doing considering the EPA cert and the tax incentives, but I suppose if you can get your furnace to comply without changing the design, go for it.

 

[Singed Eyebrows]

Mike, I don't know of any of the fancy forced-draft European or domestic gassifiers with refractory afterburner chambers that will sustain secondary combustion without the draft fan on. Maybe some cases with exception chimneys can but it's not part of their design. You want to see the rocket, you have to turn on the fan.

Idling just sucks, but sometimes under some conditions you have to live with it.

Or figure out a way to store the heat from a real secondary burn if the house can't use it at the moment.

Dave, Atmos is the exception. It is designed to keep right on burning(secondary included) on power failure & can be run like this if desired. The draft needs to be 25pa or approx. .1 water colume to accomplish this. It does drop down to 70 percent in this mode & takes in air through a Samson controlled flap that works without power anyway. This is one of the only boilers I know that is built like this. With the induced draft fan on it just roars away normally(or so I am told, mine is not installed yet), Randy

 

[laynes69]

Its been stated in the past by keith that there are no tests currently for furnaces. Thats wrong. I spoke with the makers of the caddy, which they used onmi labs in canada. They said their furnaces required alot of testing and engineering along with alot of money to get them certified. When their test results are where they want them, then they send the furnace to omni then that paperwork goes to the the EPA to get them certified. Its not that they can't test them, its that almost all furnaces with a 6+ cubic foot firebox are almost impossible to get a burn clean enough to pass EPA's requirements. Thats where manufacturers feel that its a waste of money considering they won't pass. The design of the caddy is advanced. Alot goes into clean burning technology. The placement of air, insulated fireboxes, etc. With a firebox the size of the yukon, woodchuck, firecheif, usstove, etc. would require alot of extra air to get them to burn clean. One little tube ain't gonna cut it.

 

[mike1234]

Go read through the thread mr expert and tell me one effin place you see the mention of one little tube?

Its been stated in the past by keith that there are no tests currently for furnaces. Thats wrong. I spoke with the makers of the caddy, which they used onmi labs in canada. They said their furnaces required alot of testing and engineering along with alot of money to get them certified. When their test results are where they want them, then they send the furnace to omni then that paperwork goes to the the EPA to get them certified. Its not that they can't test them, its that almost all furnaces with a 6+ cubic foot firebox are almost impossible to get a burn clean enough to pass EPA's requirements. Thats where manufacturers feel that its a waste of money considering they won't pass. The design of the caddy is advanced. Alot goes into clean burning technology. The placement of air, insulated fireboxes, etc. With a firebox the size of the yukon, woodchuck, firecheif, usstove, etc. would require alot of extra air to get them to burn clean. One little tube ain't gonna cut it.

 

[john26]

Energy king builds a furnace that is rated at 78% efficency ts is achieved through a secondary burn chamber. I cant find the size of the fire box on thier specs but I have seen one in person and it appears to be as big as my woodchuck fire box which is 7.7 cubic feet. It is epa rated and quaifys for a tax credit but it is a bit pricey at $3400. I assume this one was tested by epa woodchuck claims 78% efficency on a 2900 with a catalyst I wouls like to see the paper work on that.

 

[laynes69]

First off I'm no expert. Second off theres no need to be a smart ass, It was a figure of speech. I was commenting that you could do it im sure but it would require alot of extra air for the secondaries. You get a large load of wood, and when it outgasses and you shut down the primary you'll need alot of air and heat to get them to light off. If enough oxygen isn't present in the secondaries to continue a burn the fire will smolder and produce little heat. Both the ports on the caddy are 1 1/2 inches, thats with a 3.5 cubic foot firebox. If you modifyed the furnace, I would keep those 2 sides closed, and place 3 or 4 tubes connecting to the sides. You want those extra tubes in the path of the flames. Things will change in the future on central heaters.

 

[mike1234]

Thank you, that was much more helpful. I am beginning to be convinced (by you and others) that it may not be possible to mod this without putting a new hole in the steal someplace for more 2ndary burn air, and I am not willing to do that. The energy king listed above has just one tube but it looks to be 2" or maybe 3"? square.

A lot of people say no, or probably not, no one has said yet, your plan will work - so far.

First off I'm no expert. Second off theres no need to be a smart ass, It was a figure of speech. I was commenting that you could do it im sure but it would require alot of extra air for the secondaries. You get a large load of wood, and when it outgasses and you shut down the primary you'll need alot of air and heat to get them to light off. If enough oxygen isn't present in the secondaries to continue a burn the fire will smolder and produce little heat. Both the ports on the caddy are 1 1/2 inches, thats with a 3.5 cubic foot firebox. If you modifyed the furnace, I would keep those 2 sides closed, and place 3 or 4 tubes connecting to the sides. You want those extra tubes in the path of the flames. Things will change in the future on central heaters.

 

[john26]

Question Its hard to tell from your drawing but are you running those tube into the secondary heat exchanger? Or are you going below the secondary heat exhanger in the the top of the primary burn chamber, the top of the cylndrical burn chamber?

 

[mike1234]

What you can't tell from my "professional" drawings where I am running them? I am so insulted.
I was planning on running them inside the primary burn chamber.

The furnace does work extremely well when it has to work, last night it was -5 or so, went to bed and at 11, house was 73, woke up at 5 (early day at work) to a house that was 70, with 4 inches of coals still glowing, and now it's back on the way to 73. When it is working hard, no smoke comes out of the chimney, only heat waves. When it idles at all is when it is inefficient, and that is what I am trying to fix, or at least improve.

Question Its hard to tell from your drawing but are you running those tube into the secondary heat exchanger? Or are you going below the secondary heat exhanger in the the top of the primary burn chamber, the top of the cylndrical burn chamber?

 

[CrappieKeith]

I hear what your saying Mike.
I will ask to see if we can get a glass door to shoot some video through.All I can do is ask.

As to burn times....no manufacturer is really any better. Smaller fires do burn hotter and are more effcient.

Anytime somebody want to make mods I'm typically against them and in most cases something is wrong in the install or they are burning wet wood.
In your case Mike I don't hear any of that.What I am hearing is that you are trying to make your SJ125 even more efficient.
True they are built like a tank and can take massive abuses. All I know in the end is people do what they are going to do.
Whatever you decide on...good luck Sir.

As to Layne....you have no idesa what you are talking about. It's been clear to me for sometime that although your heart is in the right place your head is not.
Your lack of knowledge is evident when it comes to some things.
At this current time there is no bonfide accepted test for furnaces as too particlates of emmisions in the U.S.
As a matter of fact I had this very same conversation with Omni testing labs. There is a test being passed around in Canada that has yet to be accepted and that we assume the EPA will adopt this new set of critera in testing once Canada does.
Some folks get confused with efficiency vs. particulates.


Back to Mike.....your furnace has a 400 degree stack temp when the barometric draft regulator is set to .03" of W.C.
If your wood is dry then your going to have a 1500-1600 degree fire in there or a bit hotter.
That means your at around 75% which is not the same as the lower heat method which says that those numbers would jump by 10-12%
Here's where I get a boner...marketing.....it is physically impossible to burn wood and be anything more that 83%. At 83% the stack temps would be so low that they would continuessly make creosote.
They would also need a flue fan or draft blower to blow out the smoke that can not rise on it's own any longer,plus you would need a drain hose like you'll see on a condensing gas furnace to drain off the liquid.
This condensation is also very acidic and therefore heat exchangers would need to be of a high grade stainless steel.
You could bump up the fire temp instead of putting out cooler emmisions ,but then your getting into the range of moleculary changing the steel itself.
I understand that the U.S. goverment has allowed U.S. makers to play on the same field as the Europeans by allowing this low heat method of testing,but in the end it's misleading the public.

The testing procedure we have when it comes to wood burners is not all that equall either. I have talked to all of the testing facilities about this during the bid process we went through and they all confirm that if the "said" furnace was unable to meet certain criteria that there were "things" that could be done to improve the testing results.
The point is results can be modified....the testings are questionable at best , but our well educated lawmakers..LOL have made rules we must abide by.

so Mike...where does that leave us....get your wood as dry as you can outside of kiln drying it.
Make sure you have the correct size flue and that the flue /draft is set properlly.
Also your t- stat could be to close to the heat source.Having it further away could get your furnace to call for heat more often.
Your blower could be too big satisfying your stat to quickly...I doubt either of those things are issues.
Closing down the draft blower's disc could have an effect that has the stat call for heat more often.
In the early point of our heating seasons we can make a ton of heat with that Jack and it will idle more often because the heat load is less or lower.
As we get into colder temps the call for heat will increase therefor your furnace will run more efficiently.

Sometime guys think that wood or coal operates in this process of what's called continueity of operation. Some even think that wood has an A.F.U.E rating(annual fuel utilization equipment) that operate with continueity. Wood does not and it will always be cycling if it has a stat making the call for heat on a dampering system.
The more it calls for heat the more efficient they operate.

 

[mike1234]

Part of what you say makes sense, but I still think there is room for improvement. By the way, a glass in the top part of the door would be a very cool thing, I'd pay to put a new door in if I could get one with a glass.

As to burn times....no manufacturer is really any better. Smaller fires do burn hotter and are more effcient. Anytime somebody want to make mods I'm typically against them and in most cases something is wrong in the install or they are burning wet wood. In your case Mike I don't hear any of that. What I am hearing is that you are trying to make your SJ125 even more efficient. True they are built like a tank and can take massive abuses. All I know in the end is people do what they are going to do. Whatever you decide on...good luck Sir.

I agree, burn times are great, as long as I have dry wood, and have the baro set right. If the wood is over 20%, then when the baro is set right (.03) then you will get smoke out the front door. So the cure for smoke when you have wet wood, have the baro set at .05 or .06.

....your furnace has a 400 degree stack temp when the barometric draft regulator is set to .03" of W.C. If your wood is dry then your going to have a 1500-1600 degree fire in there or a bit hotter. That means your at around 75% which is not the same as the lower heat method which says that those numbers would jump by 10-12%

OK, but during idle we are not at 75%, and I think a different way of doing the secondary burn gets the idle closer to 75% - that is what I am trying to accomplish. I also think that what I am proposing is such an easy fix for your company, you'd be willing to give it a shot - what else do you have to do but take someone off production to weld up a secondary for the superjack? :cheese:

What I have concluded is that if I can get one of my professional welder friends to work with me on this, I will probably give it a try, maybe in March. We will only tack it in, and if it works, great, if not, a little grinding and ... no mod. I would still like comments about what might or might not work better than what I have proposed.

 

[Gooserider]

Two comments...

OK, but during idle we are not at 75%, and I think a different way of doing the secondary burn gets the idle closer to 75% - that is what I am trying to accomplish. 

One minor issue is that if you DO succeed, you will essentially no longer be idling, but producing some serious amount of heat... This kind of defeats the purpose of having an idle mode?

I also think that what I am proposing is such an easy fix for your company, you’d be willing to give it a shot - what else do you have to do but take someone off production to weld up a secondary for the superjack? 

It isn't as simple as that - might only cost a couple hours labor to build a prototype, but before a stove maker could sell it, or even officially admit that it existed, there would have to be a HUGE amount of testing that could cost hundreds of thousands of dollars - not just for emissions, but also UL safety ratings and assorted other labels - While one could argue that it's a good thing from a safety standpoint, I suspect that one could make a strong case that stove technology (and probably the same for other such stuff) is majorly held back by the problems of getting past all the testing and labeling requirements...

In addition, current legal precedents and our modern-day litigious society puts CK and others in a similar "professional" capacity in a very awkward position - if they even hint at telling you do something that isn't in the install manual / listings for the appliance, and anybody finds out, then he has potentially handed any ambulance chaser a slam-dunk win if some klutz manages to burn his house down... I am NOT speaking for him, but even if he really wanted you to try it and see what happened, he couldn't come out and say so in so many words....

Gooserider

 

[mike1234]

1. But isn't being efficient EVEN during idle the reason you bought your wood stove? Isn't that the reason for catalytic stoves? It would mean I would have to be careful about the amount of wood I put in. Now if I overload it, I can just idle it all day - produce creosote like crazy, and too much smoke, but I can do it. If it was burning all of that smoke, and I overloaded it, I'd have to open all the windows, but I would learn to put in less wood meaning I would burn much less wood.
2. I did have a smiley face after my comment about yukon testing this. Like I said in a comment somewhere above, they are not motivated to change, it sells, it works well, it's built well, and as you point out, no new testing costs, no new lawsuits ....

I am much happier with the furnace the colder it gets, it's much more efficient, less idling, and I can sleep all night because I get loooonnnngggg burns (went to bed at 10:30 last night, slept in and woke up at 6 am, still have 3" of hot coals, house is at 69, it's 6 °F outside) etc... I don't think any other furnace on the market would do this for me given the size of my house. Maybe I am trying to achieve "wood burning nirvana" and it's just not possible.

I do wish a few of you creative engineers thinkers would say, ok if your going to give it a try do it this way instead ..... when I melt the superjack I promise not to sue you.

Two comments...

OK, but during idle we are not at 75%, and I think a different way of doing the secondary burn gets the idle closer to 75% - that is what I am trying to accomplish. 

One minor issue is that if you DO succeed, you will essentially no longer be idling, but producing some serious amount of heat... This kind of defeats the purpose of having an idle mode?

I also think that what I am proposing is such an easy fix for your company, you’d be willing to give it a shot - what else do you have to do but take someone off production to weld up a secondary for the superjack? 

It isn't as simple as that - might only cost a couple hours labor to build a prototype, but before a stove maker could sell it, or even officially admit that it existed, there would have to be a HUGE amount of testing that could cost hundreds of thousands of dollars - not just for emissions, but also UL safety ratings and assorted other labels - While one could argue that it's a good thing from a safety standpoint, I suspect that one could make a strong case that stove technology (and probably the same for other such stuff) is majorly held back by the problems of getting past all the testing and labeling requirements...

In addition, current legal precedents and our modern-day litigious society puts CK and others in a similar "professional" capacity in a very awkward position - if they even hint at telling you do something that isn't in the install manual / listings for the appliance, and anybody finds out, then he has potentially handed any ambulance chaser a slam-dunk win if some klutz manages to burn his house down... I am NOT speaking for him, but even if he really wanted you to try it and see what happened, he couldn't come out and say so in so many words....

Gooserider

 

[Gooserider]

1. But isn't being efficient EVEN during idle the reason you bought your wood stove? Isn't that the reason for catalytic stoves? It would mean I would have to be careful about the amount of wood I put in. Now if I overload it, I can just idle it all day - produce creosote like crazy, and too much smoke, but I can do it. If it was burning all of that smoke, and I overloaded it, I'd have to open all the windows, but I would learn to put in less wood meaning I would burn much less wood.

I wouldn't say that idling was even on the menu with my cat stove (which doesn't work for beans BTW) - Yes, I can turn the burn rate up and down, but if I'm burning, I'm making and putting out heat to at least some degree...

In general I want to design to avoid idling, but not if that means making a lot of heat when I don't want it to, and really those are the only choices.

Another issue you might find problematic, which has been touched on, but not really emphasized, is that one of the other ingredients needed for 2ndary combustion is to have enough heat in the firebox to sustain the secondary flames - this is about 1200°F, and it is difficult to maintain that kind of temperature without some fairly enthusiastic fire burning - this is one of the reasons why secondary tube stoves are generally considered harder to get long burns and low heat outputs out of - they have to burn fairly hard in order to keep the firebox hot enough to burn the smoke... Because a cat is supposed to light off at a lower temperature, it can keep burning longer and lower because it can get away with a lower firebox temperature... With the Jack, you may find that even if you add more air, it still won't give you sustainable secondaries because the firebox doesn't stay warm enough.

2. I did have a smiley face after my comment about yukon testing this. Like I said in a comment somewhere above, they are not motivated to change, it sells, it works well, it's built well, and as you point out, no new testing costs, no new lawsuits ....

Understood, I just wanted to fill in the extra details as to why R&D in the stove world is such a problem... Keep in mind also that even the big brand stove makers sell relatively few units, which means that you have much less margin to defray your costs - If testing costs $25K, but you sell thousands of units, i.e. like an oil boiler company, then the testing only costs a few dollars per unit, no big deal... But if you only sell a few hundred units, then the cost per unit goes way up, which hurts sales, etc...

I am much happier with the furnace the colder it gets, it's much more efficient, less idling, and I can sleep all night because I get loooonnnngggg burns (went to bed at 10:30 last night, slept in and woke up at 6 am, still have 3" of hot coals, house is at 69, it's 6 °F outside) etc... I don't think any other furnace on the market would do this for me given the size of my house. Maybe I am trying to achieve "wood burning nirvana" and it's just not possible.

Glad the unit is working out well for you - and what you describe is what we've been saying all along, as being typical of most any setup - they run better when it's cold, shoulder season is problematic for any unit...

I do wish a few of you creative engineers thinkers would say, ok if your going to give it a try do it this way instead ..... when I melt the superjack I promise not to sue you.

It isn't YOU that we are worried about so much as the "George" that is likely to come along a year from now, read the thread, and tell his pal "Harry Hamhands" about it - and when Harry creates his own totally screwed up interpretation of what we told you, and burns his house down, he will blame us for it... (In a rational world, it wouldn't work, but todays courts are far from rational....)

Gooserider

 

[CrappieKeith]

Well GooseRider...you pretty much covered it...good job.

There is one thing I'd like to point out that has already been eluded too.
What Mike is looking for is "continueity of operation".
With solid fuel this will never occur.
As it's been stated.When burning wood the cleanest way is having hot fires.
This means there's a call for heat. So as a user and I am one of them we need to learn how to properlly size the wood load against the "call" for heat.

I choose to not pay for gas heat. This is a choice I have made. The ramifications are this. I must "work" for the dollars I am earning. This work entials me to load my furnace, dump ashes and clean my flue.
I also know to burn the dryest wood I can find to avoid excessive creosote build up.
If I take responsibility in how I operate"which changes as my heat load changes" my furnace stays pretty clean and at the end of the year I'll take those thosands of dollars that I used to give away to the gas guys and redirect those monies into my bank account.

Mike we have choices.Some folks say I do not want to deal with the early and late season issues so I'll burn a little liquid fuel until it gets cold enough that my wood furnace really burns cleanly because of the constant call for heat.
Others like myself burn wood as soon as it hit's 50 degrees.
I understand your interest in tweaking. I just do not think that getting every pennies worth of heat is actually possible.
It sorta reminds me of an archetect. Building a big building on paper is different that actually what the carpenters have to deal with.
Sometimes there's no bearing wall in place to handle a span the archetect designed on paper.
I've been involved in situations like this.
I've seen 1st hand how it can look good on paper ,but then when you try to put something into practical use there are still problems.

We appreciate your ideas....it impresses me that you have put so much thought into making a good product even better.

 

[webbie]

there would have to be a HUGE amount of testing that could cost hundreds of thousands of dollars - not just for emissions, but also UL safety ratings and assorted other labels - While one could argue that it's a good thing from a safety standpoint, I suspect that one could make a strong case that stove technology (and probably the same for other such stuff) is majorly held back by the problems of getting past all the testing and labeling requirements...

There was an article recently in our trade pub relating to this....estimate was 700K or so for a steel unit from start to finish - for all development, testing, etc.

Even if a company like Yukon did it on the cheap using their own folks and some subs and labs, you are still talking a couple hundred grand. It would also be better, in such a case, to start from scratch rather than modify.

In other words, it's kinda like putting a hybrid engine in a big honking SUV. Neither fish nor foul

Yukons other technology, BTW, which they use in their multi-fuel and Klondike add-on, does use natural draft and a decent secondary air system which was way ahead of it's time in 1978...and, in my experience, did actually work (while most other units at the time that claimed to work, did not).

A lot was related to the firebox size and insulation of it...the Klondike, etc. have massive firebrick walls as well as compact fireboxes.