Secondary Tube Type Stove Burners - Quick Question

[leeave96]

When you are burning your stove after reloading or from a cold start and your secondaries kick-in, do the secondaries alone create enough heat within the firebox to keep the secondaries going until the wood outgass to charcoal? How much do you rely on the splits in the firebox burning to keep the stove temps up such that there is enough heat to light off and keep the secondaries going?

I was looking at some videos on youtube and a lot of secondary burn type stoves appeared to have smoldering splits, i.e. no flames coming off them, but at the top of the stove was a cloud of active secondaries. Some of the titles of the vids said their stoves were cruising. I haven't been able to do this with my Englander 30 (and really didn't expect to do so from the get-go), so seeing these smolder-ish burns with secondaries going - which resembles my cat stove's smoldering burn, is the genesis for my question.

Soooo - do the secondaries in your stove keep the stove hot enough to maintain the secondaries or do you have to keep the flames going (via more primary air) off your splits to keep the overall stove temp up to maintain the secondaries.

Just curious.

Thanks!
Bill

 

[shawneyboy]

Once my stove gets up to temp, my air is usually closed completely. The airwash system on my stove usually keeps some flaming wood in the front of the stove. Do I need those flames? No, once I get her going the secondaries will keep her in cruise control, at an extremely high temp, and are self fulfilling.

Shawn

 

[MarkinNC]

I have never been able to sustain that. I can get that secondary only combustion if I run my stove up hot and then cut back on the primary air a lot. The wood will out gas and combust for a little bit then the flames will die out forcing me to feed it more air. My stove would not cruise on secondaries only. Maybe somebody else has a stove that would do it, but I doubt it.

It is a handy way to demonstrate to someone new what secondary combustion is IMO. All this internet videos are short I have noticed.

 

[Fod01]

Great question. I think that would depend on the quality of your wood. I bet that the higher the MC, the more flame off the fuel you would need to sustain temp.

Gabe

 

[shawneyboy]

Not only quality of wood, but also type of wood. ie. Pine off gasses extremely fast, you (at least I) can get extreme secondaries for a shorter timespan as opposed to well seasoned Oak which off gasses slower and I get slightly lesser secondaries but for a much longer timespan. It also will depend on your draft, which is effected by your setup. With the exact same stove, and the exact same setup, in different parts of the country the burn could be different. There are so many varriables.

The important thing to look at is do you have smoke ? That will tell you if you are burning properly.

Shawn

 

[basod]

My Clydesdale will burn like this after about the second load. I never briing it up to temp too fast from completely cold start so maybe 2 loads on a cold start.
I find the most fdesirable burn/cruise/auto-pilot condition is a good coal bed. Load some dry splits with air open in the morning and open the air up, this burns off any carbon buildup on the glass, heats the stovepipe backup and replenish my coal bed from overnight. Then I'll load some bigger splits, get them charred~20min and cut the air off. the flames just dance off the logs kind of neat how slow the falmes roll around the firebox.

 

[Todd]

I have never been able to sustain that. I can get that secondary only combustion if I run my stove up hot and then cut back on the primary air a lot. The wood will out gas and combust for a little bit then the flames will die out forcing me to feed it more air. My stove would not cruise on secondaries only. Maybe somebody else has a stove that would do it, but I doubt it.

It is a handy way to demonstrate to someone new what secondary combustion is IMO. All this internet videos are short I have noticed.

+1 I haven't been able to sustain that with my previous non cat stoves, always had to tinker with the air to keep a little more flame near the wood.

 

[Wood Duck]

In my stove the secondaries sustain themselves a lot better after a reload than from a cold start, but I can't shut the primary air all the way down and expect to maintain a hot temperature for long - or at least not every time. Sometimes it happens, but most of hte time I have to leave the primary air supply partially open to maintain a little flame from the wood and good secondaries. As Shawnyboy says, the type of wood makes a difference. I don't have much pine, but I have Red Maple that gasses faster and sooner than oak, and so a load of Red Maple will have better secondaries sooner than a load of oak. With oak the secondary burn lasts longer, but it overlaps the coaling stage, and when I burn the coals I need more primary air.

 

[cptoneleg]

Afew days ago BB posted how to load a stove read that, it improved my secondaries, and burn time, The Hearth Room titled( I keep Getting too hot)


It works for me with small loads or full loads. It should be posted as how to load a stove :zip: for best secondairy burns or something like that.

 

[begreen]

That wood gas (secondary burning) is fuel. What you are looking to do is to back off on the air enough so that you hit a point of balance where just enough air is being consumed to sustain secondary combustion, but as little as possible. When you reach stasis, there will be plenty of heat to keep the wood cooking (think oven here), yet not too much. Too much air will consume the wood and gas too quickly. The visual indication of this balance point when the flames get lazy and waft over the wood.

 

[DexterDay]

One of those vids might have been mine. And as said above, it was 80% Pine in there 4 splits pine-1 split silver maple) . The stive does have to be about 600*, but once the wood is charred pretty good, I shut the air down to about 1/2"-3/4" closed and its mainly secondaries. This only lasts for maybe an hour. I have another video I am going to post soon thats about 5 min long. This video is of the "tunnel of love" that BB talks about. Pretty wicked show.

After trying a few loads of Ash recently, I have found where I need to keep the Primary open much farther. The Ash is maintaining a much longer fire (obviously) even though my Primary is out more. I can get secondaries only with it, but only for a couple minutes and then it wants to snuff out. The Ash is leftovers from last year (I have a Pre fab fireplace too) and is plenty dry (17%). It needs the air and cant sustain secondary only burns. The Pine on the other hand is Great for that. If the air isnt closed most of the way, it gets hot and scary really quick.

Still experimenting. And have only burned a couple different types of wood. Going to give some Elm a shot this weekend. Having the time to watch and observe a lot of the burn helps me. Your threads have brought light to a couple questions I have had and also a few things I never thought of or tried yet.
The coals to the front is the biggest one. The Cigar Burn. Love it. I was a "spreader" before and didnt know any better.

Tried the magnet thing this week also. Not really a fan... I took them off and will leave the stove as is. The doghouse really helps to keep the temps up in the firebox, which helps sustain secondary combustion (again, mostly pine burnt so far, with some silver maple).

 

[Treacherous]

Once I get my stove top in the 500-600 range I can close the air all the way on my Lopi. Secondaries will continue until outgassing has completed.

 

[TvSteve]

I have never been able to sustain that. I can get that secondary only combustion if I run my stove up hot and then cut back on the primary air a lot. The wood will out gas and combust for a little bit then the flames will die out forcing me to feed it more air. My stove would not cruise on secondaries only. Maybe somebody else has a stove that would do it, but I doubt it.

It is a handy way to demonstrate to someone new what secondary combustion is IMO. All this internet videos are short I have noticed.

Same here. If I cut back a 600 degree burn the secondaries will extinguish and the wood will begin to smolder with visible smoke from stack. I noticed with this stove there is a fine line from smolder to a clean burn. I burn lots of pine and just a 1/4" increase of air will clean up the smoke and this is on a 650 stove top tempreature.

 

[begreen]

All depends on the wood, the stove, the draft and the operator. We sometimes get multi-hour secondary displays without any fiddling in the T6. In the Castine, as long as the wood was good, the secondary display was shorter, but when done, there was no smoke. At that point the wood should be at the charcoal stage and not smoke.

My buddy just put an Endeavor in his shop, so I'll check out how his burns sometime this winter.

 

[MarkinNC]

I tried closing all the way my air control tonight with a 550 degree stove (it had been 600). The wood was largely red maple seasoned about 14 months, temp upper 30's, chimney system about 15 feet long. It out gassed initially for 2 minutes or so then the fire went out. As Todd posted, I also have to have a little flame on the wood, a lot of the flame is blue, and there is a lot of out gassing with secondary combustion. With this set up the stove top is about 500 degrees and this works well for over night burns.

 

[rdust]

When I burned a non cat I always kept a little flame going. When it got really cold I had no choice, I would close the air all the way and it would still be burning wildly. If I was around I would always open the air a little once it reached the coaling stage to help burn the coal bed down and pull more heat out of it.

 

[wkpoor]

Those of you that speak of closing down the air all the way. Do you know if that is really happening or that the lever just won't move any farther. My guess is most EPA stoves don't allow complete shutdown of the primary air and if you really could I'm not sure if the secondaries would stay lit. Even with a valve that will shut completely they aren't air tight valves so there will be some leakage and depending on draft that may be enough.

 

[SlyFerret]

I try to adjust the air so that I have a balance of a little flame coming from the splits, but also strong stable secondaries.

I don't have enough chimney to have enough draft to close the air all the way.

I also don't have enough house to keep my 30 hot all the time. I tend to fire off one load in the morning and one load in the evening. I might have enough coals to get things started, but the stove itself is usually pretty cool.

Ohio almost never gets cold enough to keep a good coal bed. Maybe if I could, I could close down the air all the way.

-SF

 

[BrotherBart]

Half of the heat in a load is in the coal stage. Ya gotta keep enough primary air, be it though the air control or the unregulated whatever designed into the stove, to get the most heat out of that pile of coals. If you find a big black mass of crap in the back of the stove in the morning, ya screwed up. Secondary air won't do that for you. Aimed the wrong way.

Better that it burned and heated the couch and walls that will give the heat back slowly.

 

[DexterDay]

Those of you that speak of closing down the air all the way. Do you know if that is really happening or that the lever just won't move any farther. My guess is most EPA stoves don't allow complete shutdown of the primary air and if you really could I'm not sure if the secondaries would stay lit. Even with a valve that will shut completely they aren't air tight valves so there will be some leakage and depending on draft that may be enough.

The 30 has all kinds of air coming in. Even when you thinl its closed. The Primart, Secondary, and Doghouse air. All 3 of these points let air into the Firebox. The doghouse letting in a lot of it.

 

[shawneyboy]

Those of you that speak of closing down the air all the way. Do you know if that is really happening or that the lever just won't move any farther. My guess is most EPA stoves don't allow complete shutdown of the primary air and if you really could I'm not sure if the secondaries would stay lit. Even with a valve that will shut completely they aren't air tight valves so there will be some leakage and depending on draft that may be enough.

When I say shut her all the way down, I mean by the primary control. I think the vast majority of peeps here, not all granted, understand what is meant. My stove has unregulated secondary air so.... No it is not a complete shutdown of all air.

Shawn