secondary burn tubes

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

bkdft

New Member
Feb 8, 2011
7
GA
just wondering, if you were to install 2nd burn tubes and the stove didnt have a glass door........when and how do you know how much air to introduce thru the 2nd tubes? is it a temp thing? i get the whole concept and agree but can someone educate me on the use of the tubes?

thanks
 
Could go by surface temps. Shoot for 500 deg top temp, close the air down, wait 10 minutes and look at the chimley fluke.
 
Franks said:
Could go by surface temps. Shoot for 500 deg top temp, close the air down, wait 10 minutes and look at the chimley fluke.

That's exactly how it worked on my stove when I put them in. They'd light off at around 450-500 degrees stove top temp. I'd then close the primaries down some. Never had to close the secondaries at all...just lucky with the size, I guess.
 
You'd be better of just buying a used EPA approved stove rather than trying to install secondary air tubes in an existing stove. The modern stoves go through a lot of expensive R & D to come up with a design that works. The idea is to have channels built into the stove that pre heat the combustion air and then brings it into the stove through secondary air tubes under the baffle plate that are hot. As this super hot air comes out the holes in the tubes it provides the heat and oxygen necessary to ignite the gases driven off the wood. They look just like gas jets when working properly, pretty cool to watch.
 
The air only comes through those tubes if the stove is drawing hard for air and not receiving it from the primary. If the primary air is open too far, you will not get secondary action. Close the air down on a hot stove and the secondaries will come to life to feed the stove. By their design, the way (as it angles, spacing, etc) they feed air provides a more complete burn than the primary can alone.

pen
 
You need to open up the primary air control all the way and burn the stove hot for about 20 min, get the chimney good and hot to establish a good draft and then shut the air control down. Then you'll see the "gas jets" coming out of the holes. If all the conditions aren't right, then the gases from the tubes won't ignite.
 
I'm really thinking about this too. The cost of replacing our old stove with a new one we have picked out is turning my stomach, especially when the whole point is to save money right? And if it actually works better, then was toying with the idea of fitting on a glass door, repainting the thing, and replacing some of the old firebricks.
 
If the stove wasn't designed to use a glass door with an air wash system it will constantly be dirty and you won't see anything through it anyway. You don't have to buy a new stove, just a used EPA stove with a glass door. That would make more sense.
 
Hi,

I did this project last summer (click on attached link). It didn't cost much, the baffle board from Quadrafire cost more than the rest of it combined ($125, if memory serves). The labor and welding was all free, but may not be for you if you don't know someone with a welder and grinder. It works great; I use a stovetop Condar thermometer and look at the chimney cap to determine if it's working. This made a big difference in the stove's ability to hold fire and coals for a longer time period. And when really cranking, I can see 800 °F on the stopvetop thermomter. It will hold at 600 or higher for a lot longer than before the retrofit.

Considering that an Englander 30 is going at a real good price right now, I don't know if this type of retrofit is worth the time/money if you don't have some aptitude and the proper tools to do it yourself. But I like to experiment and build things, and already had the stove, so it was a great project for me.


https://www.hearth.com/econtent/index.php/forums/viewthread/60745/
 
Wood Heat Stoves said:
If the stove wasn't designed to use a glass door with an air wash system it will constantly be dirty and you won't see anything through it anyway. You don't have to buy a new stove, just a used EPA stove with a glass door. That would make more sense.

Yeah, an airwash would be part of the plan or else the glass would be dirty. I suppose if you could find a really cheap used stove compatable with your current setup then that would be an option. Personally I've never seen one that didnt look like crap and if I am going to invest more than a couple hundred bucks I am going to buy the new stove that we both actually like.
 
I did the secondary burn tube retrofit on my mid 80s Country Flame. I'm pleased with its performance, longer, hotter and cleaner burn. The glass actually stays cleaner until the temp starts dropping but that’s ok because the next load will burn most of it off. My next move will be to install a cat.
 
While I agree with a previous post that either a new or used epa stove might do a much better job than a retrofit job, I think there's a place for some of these retrofit jobs. I've read a couple of places that approximately 75% of the stoves in use are pre epa stoves. The only real successful programs to get them out of circulation combine some sort of government incentive to replace them, along with regulations and fines to keep people from burning the older stoves, or requirements that they be removed when a house is sold.

New stoves, while nice and maybe a major improvement over the stoves they replace, are not cheap. Used epa stoves, in my area are a rarity. In my case, I had a good old stove that did a great job heating my house. I wondered whether I'd get a replacement that did as good a job heating the house as the current stove. So even if a set of retrofit burn tubes only is half as effective in increasing efficiency and cleaning up emissions than replacing the stove with a new one (and this is probably an underestimate), it's still a noticeable improvement over the way the stove burned before the retrofit. Add a cat to the picture, like I did, and I'd challenge anyone to drive by my house and suspect that I'm not burning a new epa stove.

So if the old stoves are going to be out there anyway (and all it takes is a quick drive around my neighborhood to prove that), why not attempt to clean them up as much as possible and burn them as efficiently as possible.

Scott
 
sesmith said:
In my case, I had a good old stove that did a great job heating my house. I wondered whether I'd get a replacement that did as good a job heating the house as the current stove.
Thats another thing that sticks in the back of my mind. We spent pretty big bucks on our brand new Jotul last year, our first super duper EPA stove, after reading lots of good things about it here, and I am very dissapointed with its ability to heat even that room. I can be just trying to heat the addition with it, and even on a nearly 40 degree day and the stove rock'n and roll'n and the furnace still cycles on a couple times an hour (set at 65). I mean really? A brand new Jotul and I cant even maintain room temp on a 30-40 degree day? Now I might have had too high of expectations, poor room layout, etc etc but knowing this its hard to replace the old beast that has proven it can heat the whole house, and down well below 30-40!
 
I've been burning wood for over 40 years and have used everything from an old Ashley, to an Upland to a Sweet Home to heat my house. I now have a Lopi Liberty and love it. It's an EPA stove, puts out plenty of heat, is very controllable and does everything my Pre EPA stoves did except pollute the air and it gives me more heat from the wood I burn by burning more of the gases before they go up the chimney. I realize not everyone can afford a new stove, but we'd all be better off by retiring the old polluters and burning cleaner models. It's just not realistic to think we can retrofit stoves with systems that work as well as what the manufactures have spent tens of thousands of dollars in research, development and testing in lab conditions to create.
 
I don't think my retrofit works as well as new stove; not at all. It can't compare to my Blaze King in any way (except maybe weight). It does, however, work better than it used to. I wouldn't really consider this for my 24/7 stove, it's relegated to the basement for when the outside temp gets well below 0 °F.
 
bkdft - have you looked for DIY secondary burn designs yet? There are a few here on hearth.com if memory serves and also elsewhere on the net. Pretty much every one I have seen well documented has been very successful. I wouldn’t let those who discourage creativity and ingenuity discourage you too much if you possess the skills and equipment to do it, or if you have a friend or someone that can do welding.

Here are just a few examples of a complete DIY stove being built with secondary burn and a glass door with airwash.
Secondary burn tube construction

Secondary burn tube construction part2

And the finished, completely DIY stove

Just for some ideas.

edit: I thought I checked it out prior to posting, but you have to be logged in there to see those. Sorry, contacting that person to see if I can repost his pictures directly.
 
Wood Heat Stoves said:
I now have a Lopi Liberty and love it.
Admit it, you always wanted a Grandpa Bear anyway.
Nice choice.
 
coaly said:
Wood Heat Stoves said:
I now have a Lopi Liberty and love it.
Admit it, you always wanted a Grandpa Bear anyway.
Nice choice.

I actually started out selling Timberlines, an offshoot of the Fishers. I loved my Timberline, too, especially the silver painted trees cast into the door.
 
Status
Not open for further replies.