secondary burn tubes
- Thread starter BAllen83
- Start date
-
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. -
Super Cedar firestarters 30% discount Use code Hearth2024 Click here
- Status
Huntindog1
Minister of Fire
Would be cheaper to buy you an entry level stove thats already has the tubes and it would be brand new.
What part of the USA are you in?
What part of the USA are you in?
I live in central Ohio. We really like this stove mainly for the reaon it is the perfect size for our hearth just would like to get longer burn times out of it. Any bigger of a stove wouldn't fit and would probably be over kill as this stove heats the house great. Do you think it would be to expensive to do this or unsafe or just simply to big of a project?
Huntindog1
Minister of Fire
Huntindog1
Minister of Fire
Huntindog1
Minister of Fire
Do you have room to install a top vent stove. In your avatar looks like your opening is taller than the stove you have.
Here is the thread i was reading about a guy that made is own on an older fisher stove https://www.hearth.com/talk/threads...ma-bear-or-grandpa-bear-more-efficient.15589/
Haha well fix that nc-30 and I think we can do that with you stove only issue is it's shape and is a baffle required on top of burn tubes? Also not sure if rear vent with screw with those plans or not ... Once my internet is back up ill do some research
As a twenty year Sierra burner I can tell ya that a liner, dry wood and keeping the stove burning around 500 or over is gonna do all the pup has in it. If you look up in it and see rolling blue flames up at the baffle it is doing secondary burn already.
What they called "Turbo Burn".
What they called "Turbo Burn".
Haha, thanks brother Bart. I love the stove and the heat it produces, it easily heats my hole 1 story 2,000 square foot house, I was just looking to extend burn time so i dnot have to rely on the wife so much in the evenings while I'm at work...if yout know what I mean! And tjcole.......we'll get that puppy pouring heat into that house yet!
This Sierra T-4500 heated this two story 2,500 sq. foot barn for 21 years. Unfortunately this pic was taken the night after I installed a liner and with the new monster draft I discovered the crack in the firebox behind the baffle and it ran away on me. Pulled it out and replaced it a week later.
I miss that stove. Even though the replacement heats the joint better with half the wood. Just had a lot of history with Old Brownie. Two thirds shut down and with those blue flames rolling under the baffle and no smoke out of the chimney the sucker would burn forever.
![[Hearth.com] secondary burn tubes](https://www.hearth.com/talk/data/attachments/123/123931-71a92853894319bdfa614bf1a7c7f2a5.jpg?hash=WrNnLDdDam "[Hearth.com] secondary burn tubes")
I miss that stove. Even though the replacement heats the joint better with half the wood. Just had a lot of history with Old Brownie. Two thirds shut down and with those blue flames rolling under the baffle and no smoke out of the chimney the sucker would burn forever.
Very nice set up. After I gof mine all installed with the liner and all I also have monster draft even though my chmney is only 15'. I had a busted up iinsert in when i bought the house aand it was vented directly into chimney no liner at all...luckily the house didnot burn down. Was als going thrrough 7-8 cords a sseason. Now I am down to about 1 1/2 truck loads a mnth aand house staying at 75°
Smoke Signals
Burning Hunk
Those are great old stoves and I can understand why you want to hang on to it. Depending on you'r fabricating skills and access to a decent shop you could have a lot of fun modifying it. I think you could modify the baffle and add some secondaries to it if you wanted to but it would be a bit of work. Check out the link in my sig line to see what I did to mine. I'm still working the bugs out but I will do my best to answer any questions you may have.
P.s. as stated in your other thread, for the price and ease of installation I would go with a pipe damper
P.s. as stated in your other thread, for the price and ease of installation I would go with a pipe damper
As a person who has actually converted a stove, I will reply with my observations to some of the above threads. Sorry in advance, but I will respectfully disagree with some.
1) Cost. My trip to the scrap yard for ALL steel required for the retrofit was about $40. Substantially less than a new stove of any make/model. If you double that for welding consumables, you're still well under $100. Even the NC30 is probably going to be 7, 8 or 9x that much. This assumes you have a welder, ways to cut/drill/grind metal, general skill in metalwork and fabrication. If you're planning to go to a machine shop that could eat most, if not all of the savings.
2) Heat output. Well, when the old configuration would run away with herself, I have seen stove top temps up to 950F which corresponds to a LOT of heat output. With the baffle and new controls, I can still make it run away, but it's not 'accidental' anymore. So at the extreme, I'd say heat output could be the same.
3) Burn efficiency. I probably go through half the wood I did. This seems to be a combination of better air controls and more efficient burning. Every time I see any flame at all on the secondary combustor, I know that is energy which would have gone up the flue before. The tubes are usually glowing red or orange hot and look like a full-blown gas burner with all the flames coming out, so that is a lot of recovered energy. I can also control the burn much better to stretch 6, 8 or even 10-12 hours of usable heat out of the stove, whereas before, it was much more of a 'flash fire' 3-4 hours of heat and a quick cool down.
4) Operation. This is a little more tricky. Before I had the choice of air or not. Now I can let air in under the fire, at the air wash for the glass, at the base of the fire, or into the secondary system. In a factory system, they've done the R&D and this is all gated to work off a single lever. In DIY, it's a little more tentative. It's definitely something you have to learn...kind of like running the enrichment, spark advance, etc in an old model T vs just getting in a new car and going.
5) Construction. Again, I had all the tools and equipment. If you're planning to farm it out, double check cost first. I used scrap stainless steel for the secondary tubes and supports. Seems to work great and can really take the heat. Typical red/orange operation:
![[Hearth.com] secondary burn tubes](/talk/proxy.php?image=http%3A%2F%2Fi178.photobucket.com%2Falbums%2Fw269%2Fcoreyonline%2Forangeburntubes_zps2cf3e5a6.jpg&hash=c1abfa9bd801e763c2d1f863e06302b0 "[Hearth.com] secondary burn tubes")
I estimated an opening around 10% of the 6" flue might be good start to feed the secondaries...so around 3 square inches and I threw in about one more square inch thinking it's always easy to close the gate down, but a major pain to cut this one out and weld in a bigger one. Turns out I seem to have the gate open only a fraction of what it could be...usually a square inch of opening or less. I based the hole pattern and orientation off the NC-30 (p17)
http://www.homedepot.com/catalog/pdfImages/e3/e3dda524-8c99-482d-af74-764abbb59fef.pdf
If you're seriously considering the retrofit, I'd go give an NC a good lookover, take some measurements and make some notes. Should give you a good idea of what is needed if you retrofit.
Hope this helps dispell some myths. Overall, I'm very happy with the conversion...much more even heat output, easily controlled burning, cleaner and less wood consumption. I've kicked around retrofitting a catalytic combustor to scrub that last bit of soot and gain a bit more efficiency. But the $200 initial price and estimated 3 year life is a little hard to swallow!
Either way, good luck!
1) Cost. My trip to the scrap yard for ALL steel required for the retrofit was about $40. Substantially less than a new stove of any make/model. If you double that for welding consumables, you're still well under $100. Even the NC30 is probably going to be 7, 8 or 9x that much. This assumes you have a welder, ways to cut/drill/grind metal, general skill in metalwork and fabrication. If you're planning to go to a machine shop that could eat most, if not all of the savings.
2) Heat output. Well, when the old configuration would run away with herself, I have seen stove top temps up to 950F which corresponds to a LOT of heat output. With the baffle and new controls, I can still make it run away, but it's not 'accidental' anymore. So at the extreme, I'd say heat output could be the same.
3) Burn efficiency. I probably go through half the wood I did. This seems to be a combination of better air controls and more efficient burning. Every time I see any flame at all on the secondary combustor, I know that is energy which would have gone up the flue before. The tubes are usually glowing red or orange hot and look like a full-blown gas burner with all the flames coming out, so that is a lot of recovered energy. I can also control the burn much better to stretch 6, 8 or even 10-12 hours of usable heat out of the stove, whereas before, it was much more of a 'flash fire' 3-4 hours of heat and a quick cool down.
4) Operation. This is a little more tricky. Before I had the choice of air or not. Now I can let air in under the fire, at the air wash for the glass, at the base of the fire, or into the secondary system. In a factory system, they've done the R&D and this is all gated to work off a single lever. In DIY, it's a little more tentative. It's definitely something you have to learn...kind of like running the enrichment, spark advance, etc in an old model T vs just getting in a new car and going.
5) Construction. Again, I had all the tools and equipment. If you're planning to farm it out, double check cost first. I used scrap stainless steel for the secondary tubes and supports. Seems to work great and can really take the heat. Typical red/orange operation:
![[Hearth.com] secondary burn tubes](http://i178.photobucket.com/albums/w269/coreyonline/orangeburntubes_zps2cf3e5a6.jpg "[Hearth.com] secondary burn tubes")
I estimated an opening around 10% of the 6" flue might be good start to feed the secondaries...so around 3 square inches and I threw in about one more square inch thinking it's always easy to close the gate down, but a major pain to cut this one out and weld in a bigger one. Turns out I seem to have the gate open only a fraction of what it could be...usually a square inch of opening or less. I based the hole pattern and orientation off the NC-30 (p17)
http://www.homedepot.com/catalog/pdfImages/e3/e3dda524-8c99-482d-af74-764abbb59fef.pdf
If you're seriously considering the retrofit, I'd go give an NC a good lookover, take some measurements and make some notes. Should give you a good idea of what is needed if you retrofit.
Hope this helps dispell some myths. Overall, I'm very happy with the conversion...much more even heat output, easily controlled burning, cleaner and less wood consumption. I've kicked around retrofitting a catalytic combustor to scrub that last bit of soot and gain a bit more efficiency. But the $200 initial price and estimated 3 year life is a little hard to swallow!
Either way, good luck!
Smoke Signals
Burning Hunk
First off I guess I should say that you assume all risk for any mods that you make to your stove. Take all advise that you receive on the interwebs with I big grain of salt. yada yada. Bottom line, don't burn your house down!
Now, with that out of the way, sorry no plans and looking back I would do it differently now any way. Your setup is different than mine but I think you could make it work. You would have to work around hole where the smoke exits the stove. I think that would be the biggest challenge, figuring out how to make your baffle so it doesn't inter fear with the smoke exit and so it doesn't take up too much of your fire box. Maybe you could make a frame out of tubing to preheat you secondary air and support fire brick to create your baffle. I would make my pre heater longer now that I know how it works as is.
In my stove the smoke travels to the left of the fire box, up over the brick baffle and back to the right to exit the stove, With yours, I think you would want the smoke to travel up and towards the front of the fire box, up past the baffle at then to the back where it exits. The secondaries would be under the brick baffle. I think you would want the holes in the tubes pointed towards the front of the fire box. this is my vision of how it would work, you may have a different idea and again this is all speculation on my part so take it for what its worth. One other pice of advice, make your mods bolt on so they are easy to remove if they don't work or if you need to tweak them a little. I welded some of mine to the stove and kind of wish that I hadn't now.
Now, with that out of the way, sorry no plans and looking back I would do it differently now any way. Your setup is different than mine but I think you could make it work. You would have to work around hole where the smoke exits the stove. I think that would be the biggest challenge, figuring out how to make your baffle so it doesn't inter fear with the smoke exit and so it doesn't take up too much of your fire box. Maybe you could make a frame out of tubing to preheat you secondary air and support fire brick to create your baffle. I would make my pre heater longer now that I know how it works as is.
In my stove the smoke travels to the left of the fire box, up over the brick baffle and back to the right to exit the stove, With yours, I think you would want the smoke to travel up and towards the front of the fire box, up past the baffle at then to the back where it exits. The secondaries would be under the brick baffle. I think you would want the holes in the tubes pointed towards the front of the fire box. this is my vision of how it would work, you may have a different idea and again this is all speculation on my part so take it for what its worth. One other pice of advice, make your mods bolt on so they are easy to remove if they don't work or if you need to tweak them a little. I welded some of mine to the stove and kind of wish that I hadn't now.
Smoke Signals
Burning Hunk
- Status
Similar threads
