# EPA stove newbie - secondary combustion and operation Q



## XJma (Nov 6, 2012)

Finally got our wood stove insert installed in our cape a few months ago after wanting one since we bought it. Both the wife and I grew up with 'regular' or old school wood stoves, i.e. damper up top and air on bottom, so we're not total greenhorns when it comes to running wood stoves. I think we're getting the hang of it pretty well but we're far from being experts at this thing as of yet, obviously. We have about 2 cords of fairly dry wood, and a half of 5-6 year dry wood, and lots of green. Wish I had really gotten on top of getting more dry wood earlier, but the battle has begun! Doing lots of great reading here and getting tons of invaluable info, thanx!


Anyways, I've searched and can't quite seem to get a straight answer about two things. First, wide open, 'throttle' or air control all the way in, is this the equivalent of running an old school stove with the damper open?? I understand more air when all in and less when all the way out, but what is the relationship of the damper (if this stove has a comparable part) and the air control? Does the damper close when the air control is pulled out just a hair? Or is it not quite that simple?? Wish I could find a good diagram of my Avalon Rainier or any similar stove with explanation of operation, etc.

Second Q, secondary burn. I found a video on youtube of a guy cranking his rainier wide open and then pulling the lever all the way out, at which point the flames on the logs die down and flames in the firebox shoot out of the tubes, red, orange, and blue. I can reproduce this, but can't keep it going with pure flame in the air and none on the logs for very long....again, bulk of what I'm burning is moderately well seasoned but not bone dry, no MM, yet. Basically, am I only getting secondary burn when I pull the throttle all the way out??  What about when I have it cruising at 350-650 F stove top temps (magnetic thermo verified with infrared thermo)?  I see flames dancing around the tubes, but not always all over the tubes and not always blue.  I can go outside and see shimmering heat coming out of the chimney and very little to no smoke.  Doesn't this mean that I'm both losing heat up the pipe and getting secondary burn (even though I don't necessarily see it)??? 

Thanx for reading my long post and thank you in advance for your help!!


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## corey21 (Nov 6, 2012)

Welcome.

I will tell you those youtube videos are for show.

Congrats about have good dry wood.

I get most secondary combustion with my air closed or a bit open With the air open to full you are sending a lot of heat up your pipe. Try getting it to 400 stove top then close it down in stages depending on you draft will determine your final air setting.

Hope that helps.


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## Swedishchef (Nov 6, 2012)

Welcome to the forums!

Glad to hear you have some dry wood. Now start cutting/splitting and stacking asap for next winter and the winter after that! EPA stoves need dry wood to burn properly. Otherwise you will be disapointed and frustrated (trust me on that...it happened to me my first year).

EPA stoves are very different from old smoke dragons. Usually there is no need for a pipe damper. The primary air control is able to "control" the amount of oxygen entering the combustion chamber thus allowing for a higher or lower rate of combustion of the wood.

I guess you could consider an air control fully open to be the equivalent to opening a damper on an old school stove. Leaving the primary air wide open allows for more oxygen to enter the combustion chamber and help get your fire going. I believe on the Rainier pushing "in" your rod will fully open the air. Pulling it out will close it. (http://avalonfirestyles.com/TravisDocs/100-01140.pdf)

Secondary burn is easy enough to explain: First of all, when wood begins to heat up it will off-gas. In EPA stoves there are secondary air intakes that pass air through secondary burn tubes normally located on the top of the combustion chamber. When your combution chamber temperatures get high enough and the off-gasing of the wood comes in contact with this secondary air, the gases will ignite and cause those types of flames you saw on the youtube video.

When your primary air is open and the fire is rolling with a good (400-500F) stove top temp, start closing down the primary air in stages. This will force more oxygen into the combustion chamber via secondary air intakes and will help provide a clean burn. I can't close my primary all the way on my stove, it will snuff out the fire. I usually leave it open 1/8th of the way.

When you look at your chimney and you only see vapour waves, you're going in the right direction! Do you have a thermometer on your stove pipe? I usually have mine going between 400-500 for 1-2 hours or so. OFf-gassing will cease soon enough and you won't have secondaries for much longer (at least not in my experience..they usually last 30mins-1.5 hours depending on amount and type of wood loaded into the stove).

Keep your chin up and happy burning!

Andrew


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## XJma (Nov 6, 2012)

So if I understand this correctly, no damper at all??  Interesting.  I need to see an exploded view of how this thing works!  I guess they do have an EPA stove with a big chunk cut out of it at the place I bought the stove.....  And yes, lever pushed in is wide open, out is choked.  So all this does is control intake air....crazy! 

And so the secondary burn, not something that happens during a normal burn?  Something that is difficult or at least takes a little skill to achieve and only lasts for so long?  I was kind of under the impression that the stove would do some secondary burning during most of the burn time as it's got some low emissions ratings or some such thing?? Also, I have it setup as a fireplace insert with the surround and the blower, so the stove top temp is on the very front edge of the top that sticks out past the surround, and is angled slightly down.  air front the blower comes down right on top of it too....not sure if it's possible to rig up a thermometer on the stove pipe??  Wish I was home when they installed it, but I wasn't . 


Thank you for the help!!  And I have some decent wood, not great wood, and not enough!  Wish I had acquired more wood, but tough to find the time/motivation to process and stack wood before you even own a wood stove!  In the process of becoming a hoarder myself


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## XJma (Nov 6, 2012)

corey21 said:


> Welcome.
> 
> I will tell you those youtube videos are for show.
> 
> ...


 
Wait, so with the air open it is like I have a damper on the pipe and have it open?  It feels like the air control at certain points may engage/disengage certain other internals within the stove....I need a diagram!  The manual doesn't get specific enough for a tech junkie like myself. 

I assume I have pretty good draft, I can hear whistling whether the stove is on or not with the door closed and it's masonry chimney in the center of our cape. 

So running it wide open is not going to be distributing much heat throughout the house, right?


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## Swedishchef (Nov 7, 2012)

The primary air sort of acts like a damper used to on an old stove. It controls the amount of air you let into the stove for combustion, therefore, how much the fire is "roaring".

Secondary burn does occur during a normal burn. It is part of the combustion process in an EPA stove if you operate it properly with good wood. Secondary burn is simply a phase that occurs during a burn cycle of a load  of wood.

I am uncertain if you can rig a thermometer on an insert liner...someone may chime in and be able to provide a better answer than me. LOL.

HEre is a link/video that explains secondary burn... 

Even if you turn down the primary air, you will still get a lot of heat because the secondaries will heat up the stove top quite well.

Andrew


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## XJma (Nov 7, 2012)

Thanx again Andrew, I'm starting to get a better understanding!! That video was very helpful...the internal shots of that stove look exactly like mine. I'm glad that secondary happens to some degree during a normal burn cycle!!

Needless to say I spent a lot of time last night playing with the damper! Some positions make the heat go down but it seems like 1/16" of a difference or so can make the heat increase. I guess practice makes perfect (or at least better), right?


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## begreen (Nov 7, 2012)

You want to close down the air in increments. Each time close it down until the flames start to get lazy. The let it burn like that for about 5-10 minutes. When the fire pick up in intensity, close it down more until the flames get lazy again. Ideally you want a lazy fire with the secondaries wafting occasionally over the top of the wood. A raging fire and secondary show is mesmerizing, but a bit wasteful of wood.


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## XJma (Nov 7, 2012)

Thanx begreen, I was starting to get that idea playing with the fire late into last night.  Guess what I'll be doing all night tonight too?? 

Also, are the high winds going to mess with my game?  Another storm on it's way, yeah!


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## corey21 (Nov 7, 2012)

XJma said:


> Thanx begreen, I was starting to get that idea playing with the fire late into last night. Guess what I'll be doing all night tonight too??
> 
> Also, are the high winds going to mess with my game? Another storm on it's way, yeah!


 
The high winds will cause too much draft or down drafts


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## begreen (Nov 7, 2012)

If this is your first time burning and the winds are very strong, you might want to wait a day for it to pass. It would probably be fine, but it does take a calm head if you suddenly get a downdraft and a room full of smoke. I'm not saying this will happen, just that there is the potential for something like this if the winds are very strong gusts. If the winds are strong but steady, there is the potential for having much stronger draft than you are used to. That can lead to an overfire under the right conditions. Again, this might not happen for your installation. There are a lot of variables at work, like fire size, flue height, flue location, house location, etc.. If you are unsure, I'd go back to the central heating for a day or two or at least build half full fires and don't try to go all out.


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## Swedishchef (Nov 7, 2012)

LIke Corey said, depending on where you live/your terrain setup, high winds can create a downdraft (hard to start a fire without smoking coming in) or increase your draft. In my situation, it increases the draft significantly. That means I turn down the air even more for a cruising fire as the wind "pulls" air into the stove by creating a vacuum at the chimney.

As BeGreen mention, always wait 5-10 minutes after an adjustment to see the results. A change in damper won't create an instantaneous change, it will take a few minutes.

Andrew


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## corey21 (Nov 7, 2012)

I am with begreen might want wait a day or too.

During Sandy my stove stayed at 700 for a while i don't normally go that high.

Edit. But i kept a cool head cause i know that nothing was glowing.


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## XJma (Nov 7, 2012)

I have a center chimney in a cape, and in a relatively flat area, open yard is an old pasture with trees separating neighbors who have even larger open pastures. 

I guess I'm not really afraid of a down-draft...if I can't get it going I can't get it going.  So basically, don't be surprised if it runs hot on full choke?


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## corey21 (Nov 7, 2012)

I guess I'm not really afraid of a down-draft...if I can't get it going I can't get it going. So basically, don't be surprised if it runs hot on full choke?[/quote]

After having a down draft in my shop stove i am more scared of down draft then running a little hot smoke started puffing out of that stove air vent not good.

But every setup is different have not had down draft in the mag yet.

Just be watchful more then usual running the stove in windy conditions.


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## XJma (Nov 7, 2012)

Oh, so the downdraft is not only with the door open??  What kind of conditions (other than high wind) would cause one?  Is is more likely with a cold flue?


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## eclecticcottage (Nov 7, 2012)

We have most of our pipe inside with 5 or so feet outside.  We sit between cornfields and the lake, so we get hit by winds pretty regularly.  We've found it increases draft like crazy, although it depends on wind direction as to how much.  At one point last year we had fairly high winds that hit from just the right direction, the draft was sucking the fire right up the stack, it was pretty wild.  Usually we don't get that crazy, just burn more wood quicker.  So, we keep it in mind and run smaller loads with the air choked in *IF* you choose to use your stove (insert).  Watch how much you choke the air, too much can help cause a down draft though.  Our stove is it for heat here so if it's cold and windy, it's running no matter what.


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## begreen (Nov 7, 2012)

XJma said:


> Oh, so the downdraft is not only with the door open?? What kind of conditions (other than high wind) would cause one? Is is more likely with a cold flue?


 
With strong gust and squirrely winds, expect the unexpected.


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## bag of hammers (Nov 7, 2012)

I have recently been able to close the primary air off completely for an overnight burn.  Just as begreen described it, the fire was "lazy" with some nice secondary flames dancing around.  I think I just happened to hit the perfect conditions - wood, outside temp, etc.  This isn't typical for me - I've usually been leaving the primary air open a tiny  bit on the overnight burns but I guess all the variables just lined up that night so I let it run like that and got the best (longest) overnight burn so far.  As mentioned, shut it down in stages, and watch how the fire reacts each time.  You will find the sweet spot for your setup.  It still may turn out to be just a bit of a moving target (e.g. you throw in a couple splits of well seasoned wood with one that's a bit green, and you adjust a bit).  But that's half the fun / experience IMHO.


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## XJma (Nov 7, 2012)

Well I've been applying a little bit of my new knowledge tonight and even with the high wind gusts I've had this stove cruising with a good amount of visible secondary burn for up to about an hour and a half with just minor adjustment tonight. Have had it choked way more than normally, I guess due to the increased draft. With a little bit of delay after each strong gust the flames pick up for a little bit. Having lots of fun


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## Swedishchef (Nov 7, 2012)

Glad to hear things are going well..my stove will be lit in the am!!


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## corey21 (Nov 7, 2012)

Glad it worked out.

Had to let my fire go out tonight got up to 83 in here.


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## XJma (Nov 7, 2012)

Nice and hot here in the living room, trying to get heat to go upstair....old cape, grrr. Stove pumping out tons of heat. No way I'm letting the fire go out during the first accumulation of the year!  Prospects for a great ice season are looking good!


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## hatting9 (Nov 23, 2014)

Will a crack in the secondary burn tube keep the tube from working properly?


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## thoner7 (Feb 14, 2019)

So can someone prove specifics for working one of these new reburb stoves? I just moved to a new house and I'm not doing it right..... Only had ~6 fires and I already have some staining on the chimney Cap. 

It's a new Country Hearth 2000, which I've read is a chinease knock off of an Englander??

How hot should the stove top/sides get, and for how long should it be at that temp, before shutting down the air intake??  How long should the re-burn cycle last?? I have only achieved this for maybe 5 minutes and the fire dies out.

Oh and should the fire keep burning even though the air intake is all the way shut??? Mine does, seems like a safety hazard and an energy waster when the stove isn't in use!


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## EbS-P (Feb 14, 2019)

My secondaries get more blue toward the end of the burn or when it’s burning quite hot.   I have noticed that the deeper the coal bed the quicker I can turn down the primary air.  If it’s a really hot coal bed and the stove top temp didn’t drop below 325 I can light off the secondaries and turn the air down almost immediately. If I’m not wanting to crank out the the heat I have found that starting the fire with two saw dust bricks on the bottom help regulate the temp during slower burn helping keep the secondaries burning longer on smaller load.  

Evan


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## thoner7 (Feb 14, 2019)

So I've been doing a small fire to get some coals, then throw on some larger split pieces and leave it wide open.  I'm not getting much over 500 on the top if that.  Whenever i cut the air down, those re-burn tubes don't fire like I've seen on youtube, but instead tends to slowly die out and the stove top temps get down into the mid 300s.

What temp should I cut down on the air and then by how much?


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## weatherguy (Feb 14, 2019)

thoner7 said:


> So I've been doing a small fire to get some coals, then throw on some larger split pieces and leave it wide open.  I'm not getting much over 500 on the top if that.  Whenever i cut the air down, those re-burn tubes don't fire like I've seen on youtube, but instead tends to slowly die out and the stove top temps get down into the mid 300s.
> 
> What temp should I cut down on the air and then by how much?


When you have it going good turn the air down a quarter of the way and let the fire reestablish itself, once it does turn it down a bit more. Eventually you'll find you happy spot where you can leave it. The stove will get hotter as you turn the air down as the heats in the box and not going up the flue. If it snuffs out you turned it too far.


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## thoner7 (Feb 15, 2019)

How full does the stove have to be to get them to work? Or does that not matter?

Also, should the fire still burn when the air is tortota closed? (Mine does) Maybe it's an epa feature to keep the fire from smoldering??? But it seems unsafe to me.


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## kborndale (Feb 15, 2019)

How dry is your wood?


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## thoner7 (Feb 15, 2019)

The wood I'm using..... I've been mixing some small red oak pieces of hardwood flooring and cord wood, which Was given to us by a friend.  It was split and stacked in their garage for like ten years.  At our new house I didn't have a proper place to stack it so it's been getting rained/snowed on.  But I've been carry loads to the porch to dry out before burning them. 

I thought it could be the wood so I bought a bundle of kiln dried gas station wood.  It's 8 bucks for a small arm load though so I am waiting on some more info before I give it a try. 

Mainly.... What temperature should the stove top get to typically, before I can turn down. The air.....


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## blacktail (Feb 15, 2019)

Try turning the air down half way when you hit 350-400. When the fire gets rolling again or your temp hits 500, turn it down again to 25% open. It takes some experimenting.


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## thoner7 (Feb 16, 2019)

blacktail said:


> Try turning the air down half way when you hit 350-400. When the fire gets rolling again or your temp hits 500, turn it down again to 25% open. It takes some experimenting.


Ok so if I did that...I'd turn my air down when it reaches 400, the fire wouldn't get going,  the temps would drop, not increase (so I would never get to 500)


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## EbS-P (Feb 16, 2019)

There are a lot of variables. I tend to turn down the air sooner on a reload compared to a my first fire, which I light top down as it gets the stove top hotter faster and engages the secondaries sooner.  If you haven’t tried lighting top down give it a shot. In 5 min in my secondaries are burning smoke and my stove top is 150. I use to layers of paper so if I didn’t get a good light on top I have another chance. I have found that i can’t over load it on start up  3 medium splits on bottom  two short pieces N/S then bigger pieces of kindling smaller stuff N-S again and then my little pieces and my news paper.   10 min in I’m getting blue secondaries and the bottom logs are just starting to light on their corners  stove top is 245. I might not even turn the air down at all on this first cold start load  it just depends on how it burns and it’s warm out so the draft is super strong.   
Evan


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