Confused about secondary burn

[Bushels20]

Can anyone simply explain secondary burns? I know it’s the smoke (unused fuel as a result) being burnt within the stove/insert assuming the stove temp is optimal.

What I don’t know if how long I should be able to maintain the secondary burn. Assuming the wood smokes, initially it would seem that early in the burn I should be obtaining secondary burns. I can do so for about 20-30 minutes. But ultimately the secondaries die off (at least visually).

I recently added a block off plate and insulated so secondary combustion is something I’m still learning about since I couldn’t achieve it prior to the plate and insulation.



Thanks

 

[HisTreeNut]

What type of stove do you have?

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[xman23]

For my stove to get the secondary burn going, the stove needs to be real hot. With and a big fire going I close down the primary air. The secondary burn only happens for a small period of the burn cycle.

 

[Bushels20]

What type of stove do you have?

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Napoleon 1101 insert.

 

[KindredSpiritzz]

They die out after 20-30 minutes as the wood becomes charred . My stove pipe temp has to be around 300 degrees to get my secondaries to kick in and start re burning that smoke.

 

[Highbeam]

Depends on the stove, temperature, draft setting, but most importantly the fuel. Some fuel is particularly gassy. As long as your chimney emissions are clear the system is working as designed. It’s not for looks, it’s for pollution control and just happens to look cool too!

 

[kennyp2339]

I just got a schooling in this a few months ago by @begreen and someone else, this info is relatively fresh in my head.
Secondary burn starts to occur when the internal fire box temps in approx. 1,100 deg f, this is the temp that unburnt smoke particles will re-light off.
Most modern epa "air tube" stoves supplement secondary air (through its own dedicated air inlet) that gets heated through the back or sides of the stove and then enters the secondary manifold and comes out the air tubes you see in the fire box below the baffle, the air tubes function in creating a turbulence that allows the smoke that is rising from the primary fire to mix with air and get cleanly reburnt (the gas tube effect), the result is additional heat and cleaner flue gasses.
Secondary burn times have there limits, primary the fuel type and how dry the fuel is, when I had my epa stove I would get the dancing whispering flames for approx. 2-4 hrs per load of oak, a little less in time if I was burning ash or birch, and I suppose less time if using oft woods.
Even though secondary burn times are limited, once they stop it doesn't mean the fire needs restoking, there is usually plenty of heat to be produced from the coals / left over wood, the secondary's just ran out of the prime violates that it runs off of.

 

[Bushels20]

Depends on the stove, temperature, draft setting, but most importantly the fuel. Some fuel is particularly gassy. As long as your chimney emissions are clear the system is working as designed. It’s not for looks, it’s for pollution control and just happens to look cool too!

I’m definitely getting clear/see through emissions/smoke out the chimney. I check it often but more so since the block off plate and insulation because I can keep the air intake much lower now with the upgrade. I have been watching frequently to learn where I can adjust during different temps outside. This weather, 50 degrees and breezes, I can go all the way down with 2-3 sticks in. Luckily, because it’s too hot otherwise. But I don’t like starting a whole new fire for the evening, so I keep it burning and have the wood to do so.

I have noticed the secondaries are more visible when I take air intake all the way down.

 

[Bushels20]

I just got a schooling in this a few months ago by @begreen and someone else, this info is relatively fresh in my head.
Secondary burn starts to occur when the internal fire box temps in approx. 1,100 deg f, this is the temp that unburnt smoke particles will re-light off.
Most modern epa "air tube" stoves supplement secondary air (through its own dedicated air inlet) that gets heated through the back or sides of the stove and then enters the secondary manifold and comes out the air tubes you see in the fire box below the baffle, the air tubes function in creating a turbulence that allows the smoke that is rising from the primary fire to mix with air and get cleanly reburnt (the gas tube effect), the result is additional heat and cleaner flue gasses.
Secondary burn times have there limits, primary the fuel type and how dry the fuel is, when I had my epa stove I would get the dancing whispering flames for approx. 2-4 hrs per load of oak, a little less in time if I was burning ash or birch, and I suppose less time if using oft woods.
Even though secondary burn times are limited, once they stop it doesn't mean the fire needs restoking, there is usually plenty of heat to be produced from the coals / left over wood, the secondary's just ran out of the prime violates that it runs off of.

After reading your post once, then twice it makes complete sense relative to my stove. My mainfold is directly below the baffles and looks similar to a gas grill burner, on each side.

I think the combo of my block off plate and insulation helping maintain stove temp and my good seasoned wood (which I have mastered finally and this is my first season with “true” seasoned wood) are allowing my to achieve good secondaries.

One thing I do notice now as well is; although I don’t see the flames (sometimes/always) there are distinct areas of heat on the baffles fanning out directly adjacent to the secondary manifold holes. Almost like there is non visible fire/hotter heat (if that makes sense) coming out of the holes and heating the baffles. This happens especially with oak.

 

[firefighterjake]

Depends on the stove, temperature, draft setting, but most importantly the fuel. Some fuel is particularly gassy. As long as your chimney emissions are clear the system is working as designed. It’s not for looks, it’s for pollution control and just happens to look cool too!

This . . . +1 . . . stove, temp and draft definitely affect the length of the secondary burn, but as Highbeam says the most important aspect is the fuel.

I thought I was doing pretty well in Year One of burning when I had some secondary flames . . . but in Year Two with much better seasoned wood I had the epiphany of just how much of a difference well seasoned burn makes . . . especially the first time when I had the Portal to Hell open up in my firebox.

 

[Bushels20]

This . . . +1 . . . stove, temp and draft definitely affect the length of the secondary burn, but as Highbeam says the most important aspect is the fuel.

I thought I was doing pretty well in Year One of burning when I had some secondary flames . . . but in Year Two with much better seasoned wood I had the epiphany of just how much of a difference well seasoned burn makes . . . especially the first time when I had the Portal to Hell open up in my firebox.

I did a lot of reading on here leading up to my upgrades. The ellusive but possible runaway fire is something I’m afraid of. I have not yet gotten much abode 1/2 open of air intake; and don’t plan on it until it gets really cold. Judging from your screen name, if it scares you, I would probably poop my pants and call FirefighterJonDoe.

 

[billb3]

The secondaries are burning off gases and volatiles. They are burned off /baked out of your splits by half way thru the burn if not sooner.