Secondary burn - how long does it last?

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Creek-Chub

New Member
Nov 13, 2007
215
Niles, MI
Fellas,

Another thread about secondary combustion got me thinking...

I don't seem to have any trouble getting to that stage of the game, although I'm still getting used to the 30-NC. My question is... how long generally, assuming a full load of nicely charred wood, are you seeing the secondary burn last? From the time that it kicks in, until the time it kicks out. I generally seem to get an hour to an hour and a half if I don't rush it. Is that decent, or can I do something to prolong it? Thanks...
 
Forties outside and going down to thirties tonight so I decided to wake the 30-NCL from its summer slumber tonight. This secondary has been rolling for a little over an hour and a half burning that evil pine and isn't showing any signs of slowing down.
 

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About the same here with the Jotul Oslo. It rolls and bubbles for a few hours and then the flames start to die down. I then start increasing the air (as temps start to drop) until about 200-250 reload, rechar and burn again.
Chad
 
Hey BB,

I'm burning some nicely seasoned cherry tonight, and couldn't manage the hour-long secondary burn. Any chance you could divulge how you run your 30? Say, from initial start up to putting it to bed for the night? I'm figuring it out as I go, and getting some crazy heat, but always looking to learn and wouldn't mind getting more for my mileage. I haven't timed it because I've been mixing in a bunch of willow with a little oak and cherry since it hasn't been too cold, but I'm not getting 6 or 8 hour burns, or 2 hour secondary combustion. I'm not fretting, but wouldn't mind hearing how somebody who knows what they're doing does it. Thanks!
 
Creek-Chub said:
Hey BB,

I'm burning some nicely seasoned cherry tonight, and couldn't manage the hour-long secondary burn. Any chance you could divulge how you run your 30? Say, from initial start up to putting it to bed for the night? I'm figuring it out as I go, and getting some crazy heat, but always looking to learn and wouldn't mind getting more for my mileage. I haven't timed it because I've been mixing in a bunch of willow with a little oak and cherry since it hasn't been too cold, but I'm not getting 6 or 8 hour burns, or 2 hour secondary combustion. I'm not fretting, but wouldn't mind hearing how somebody who knows what they're doing does it. Thanks!
Click to expand...

My 2 cents worth, after asking questions tonite. is no visible smoke from the chimney, not to get too concerned about creosote. I am starting to ignore the burn time thing, softwood burner here, and this morning after 10 hours the top of my insert was still warm. and the house was nice and warm. what more could ya want?

I just run my insert to about 550 top temp, then slowly start to throttle it down. And of course, east/west is best for an overnite burn, but I haven`t bothered with that cause my insert takes 20" n/s and so that is how I tend to load it. E/W it only takes 18", which maybe when it gets colder I might have to try.??
 
Thanks guys. Just to be clear I'm not getting too worked up over burn times, secondary burn times, etc. I know it all depends on a ton of variables. Just curious what other folks burning the same stove are seeing. Hell, last year I spent $400 a month in propane to keep this big drafty house at 64-66 when we were around and awake, and 60 at night. By keeping my eyes open for wood and spending my weekends hauling, cutting, and splitting, I'm keeping the house toasty and not spending a dime. Life is good!
 
skinnykid said:
I never get that long of a secondery burn using Oak, Maple, Birch.
Click to expand...

Hmmm, so how small is small for your firebox?? Sounds like something like about 1.4-1.6 cu.ft firebox? Am I correct?/
 
Do the moderators around here ever ban anyone? Seems like Rapid River might be a prime candidate, if so.
 
Mods have no banning authority. Only Craig has that option. However, thread deletion is an option. And it has been removed.

Rapid, let's stay on topic and keep to helping others ok?
 
When you folks are measuring secondary burn time, are you timing how long the secondaries are burning or when the flames die off completely. Right now my Jotul secondaries died off at about 30 minutes, but I still have very nice flames from the wood/coals.
 
Creek-Chub said:
Hey BB,

I'm burning some nicely seasoned cherry tonight, and couldn't manage the hour-long secondary burn. Any chance you could divulge how you run your 30? Say, from initial start up to putting it to bed for the night? I'm figuring it out as I go, and getting some crazy heat, but always looking to learn and wouldn't mind getting more for my mileage. I haven't timed it because I've been mixing in a bunch of willow with a little oak and cherry since it hasn't been too cold, but I'm not getting 6 or 8 hour burns, or 2 hour secondary combustion. I'm not fretting, but wouldn't mind hearing how somebody who knows what they're doing does it. Thanks!
Click to expand...

No magic to it. As many ways to burn as there are stoves and woodburners. I just don't worry about reaching secondary burn Nirvana. It was fun to play with for a while but now I just burn it like I have always burned my stoves. When it starts heading North of 300 degrees from a cold start I start backing down the primary air in three steps until it is only about a quarter of the way open. On step two and three the rolling light show is going on and then it settles down into a combination of flames on the wood and gases burning up top and the stove top around 500-550 for the rest of the burn until coal stage. Pretty boring but it keeps the stove and the house warm.

On reloads I wait till it is below 400 and just put the stuff on top of the coals and repeat the same drill. Waiting for it to come down under 400 keeps me from having to hold my breath when it rages over six hundred while the new wood out gases. On a hot coal reload you can turn the air down to less than half pretty much as soon as you close the door and it just eases back up to cruising range.
 
BrotherBart said:
Creek-Chub said:
Hey BB,
!
Click to expand...

No magic to it. As many ways to burn as there are stoves and woodburners. I just don't worry about reaching secondary burn Nirvana. It was fun to play with for a while but now I just burn it like I have always burned my stoves. When it starts heading North of 300 degrees from a cold start I start backing down the primary air in three steps until it is only about a quarter of the way open. On step two and three the rolling light show is going on and then it settles down into a combination of flames on the wood and gases burning up top and the stove top around 500-550 for the rest of the burn until coal stage. Pretty boring but it keeps the stove and the house warm.

On reloads I wait till it is below 400 and just put the stuff on top of the coals and repeat the same drill. Waiting for it to come down under 400 keeps me from having to hold my breath when it rages over six hundred while the new wood out gases. On a hot coal reload you can turn the air down to less than half pretty much as soon as you close the door and it just eases back up to cruising range.
Click to expand...

The 300 degree temp is with what type of thermometer (magnet for single wall or probe for double) ?

Thanks
 
Your times for secondary burn sound about right compared to what I usually see. I burn my stove similarly to BB. The secondary kicks in at about 300-350 stovetop on my 30. At that piont, I start backing off the air. The exact position for the air control on your stove when you're cruising will be determined by your exact setup. For me, my stove tends to cruise with the tip of the spring handle on the sir control slightly forward of the front edge of the ash lip.

I've noticed that the magic location isn't a hard fast rule. It can vary slightly depending on inside vs. outside temp, humidity, etc... (as these things can affect draft).

If you ask me, your setup seems to be working just fine!

-SF
 
Of course, I posted that my secondary burn usually lasts an hour or so but ironically last night I think it went for hours and hours. Packed the firebox full of nice dry ash, turned her down, and the stove was still hot this morning and the glass was still perfectly clean. I must have done something right last night.
 
sonnyinbc said:
skinnykid said:
I never get that long of a secondery burn using Oak, Maple, Birch.
Click to expand...

Hmmm, so how small is small for your firebox?? Sounds like something like about 1.4-1.6 cu.ft firebox? Am I correct?/
Click to expand...

2.0 I believe.
 
cmonSTART said:
Of course, I posted that my secondary burn usually lasts an hour or so but ironically last night I think it went for hours and hours. Packed the firebox full of nice dry ash, turned her down, and the stove was still hot this morning and the glass was still perfectly clean. I must have done something right last night.
Click to expand...
If your glass was PERFECTLY clean you must be doing something right. I cant burn my insert more than a couple of hours at half air without the glass getting cloudy and I burn seasoned wood.

Shipper
 
Neil said:
I have jotul f250 and have never hasd a secondary burn, how the hell do you guys get it to work?
Click to expand...

Get it up to a fairly high temperature then close down the primary air...

I start to get secondaries after just 20 or 30 seconds when I have the primary at about 1/2 open. I can FILL the box with secondaries.... the problem is I get very dirty glass as the fire dies down.

Do others also experience this?
 
I can get a little bit of haze on the glass if I let the stove cool too much (for instance after an overnight burn), but the next hot fire clears it up again.

-SF
 
my glass gets dirty from longer/overnight burns. I have to wash it off or else it don't come off.
 
Neil said:
I have jotul f250 and have never hasd a secondary burn, how the hell do you guys get it to work?
Click to expand...

I think Secondary combustion on your Jotul F250 happens on the back wall of the stove.

Neil, can you re-post the pictures of our stove when you had taken it apart? The small holes in the back look like secondary combustion air inlets. Does your stove have any primary air adjustments that you are able to operate?
 
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