Typical Fire "Life Cycle"

[brazilbl]

Forgive in advance for my lack of knowledge, I'm only a "Freshman" at the University of Hearth.com...

Reading a thread yesterday about the length of the secondary burn, got me thinking about the Life cycle of a fire. I know that there is combustion, initial burn, etc., but I'm thinking that if one knows at what point in the fire that the secondaries should light up, then one could adjust the air adjustment accordingly. It was nice to know that the opportunity for secondary burns is somewhat limited, that I shouldn't expect secondaries the whole time - especially at the embers stage.

Thinking that there will be differences between type of wood stove, construction of unit, cat/no cat, firebox size, quality of wood (moisture content, perhaps the type of wood), external temp, etc. all play in this life cycle - I understand. Most (if not all) of this knowledge will come with time/experience, but I've tried searching here, but haven't found anything.

Knowing that efficient use of the stove will yield cleaner burns, I'm looking for a resource that shows the anatomy or the typical life cycle of a given burn to gain knowledge on how to use the unit properly and efficiently.

 

[AbrK]

My secondary burn will kick in when my air is set to a little less than half and the stove is over 600f secondary kicks in and it will climb anywhere from 700 to 750f and cruise there for roughly a hour depending on the final setting of the air I get about 3-5 hours of burn time depending on amount of wood and kind of wood in the stove and my final air setting when I’m getting the house warm the stove runs much hotter and usually I don’t get long secondary burns or long burn times until I’ve warmed things up than I get set the stove in for a haul to maintains temperature in the house this all depends widely on your stove and wood types and your final air settings


Sent from my iPhone using Tapatalk

 

[cjgoode]

I only have a limited experience with these EPA stoves, but I have learned wood makes a huge difference. First fire nice seasoned very dry wood no clue what type and secondary burn started quickly and lasted most of the burn even throttled down. Very impressed. Last trip to the cabin very seasoned wood, but wet or damp and it seemed like more work then heat produced. Even the wood that really felt dry must not have been. Last day split some very dry logs and back to a great burn. Lesson learned and now I have a stack in the garage and next trip I will have a huge stack in the garage and by next fall will have huge supply in a wood shed.

 

[Poindexter]

I think wood species makes a huge difference.

Early in the burn you got sugar (sap) burning off, C6H12O6. Pre-oxygentated hydrocarbon if you will.

Once the sap is gone you have cellulose, long chains of C6H10O5. You (the fire) has to break a chunk off the chain to burn that, so working a little harder but still getting good energy out from combining oxygen with hydrogen (think Hindenburg) and combining oxygen with carbon.

Last stage, all that is left is carbon, charcoal, all your stove is doing is combining oxygen with carbon. Still making some heat, but less than previously.

I personally would save my long coaling stage fuels for shoulder season where the coaling phase is enough to keep my house warm. In colder weather, burn wood with a shorter coaling stage to make room for more sap and cellulose in the firebox.

M2c.

 

[illini81]

I think wood species makes a huge difference.

I personally would save my long coaling stage fuels for shoulder season where the coaling phase is enough to keep my house warm. In colder weather, burn wood with a shorter coaling stage to make room for more sap and cellulose in the firebox.

M2c.

Very interesting. I haven't heard anyone say this before. I'm currently burning oak and hard maple, and getting lots of coals. They are manageable, but I have to plan ahead to make sure I am timing my loads so that I'm getting enough heat in the house while also having enough time to burn coals down.

This is my first year with a stove, so my experience is limited to oak and maple. Is it true that hard woods tend to produce lots of coals, while soft woods do not? Or it it more complicated than simply hard wood vs soft wood?

 

[Poindexter]

@illini81 i would say somewhere in the middle. If you scan currently active theads on page one here you will find plenty of folks with all the various issues that can happen.

I am not trying to cast stones. The lower 48 is having a relative epic cold snap, colder than anticipated temps, winds, frost bite warnings.. thursday this week it might be the same temp in fairbanks, ak as it will be at my dads house in sarasota.

When you are looking at trees that grow near you, there is nothing wrong with focusing on the high btu stuff - except those tend to have long coaling stages. In cold "enough" weather long coaling stages arent helpful.

 

[illini81]

@illini81 i would say somewhere in the middle. If you scan currently active theads on page one here you will find plenty of folks with all the various issues that can happen.

I am not trying to cast stones. The lower 48 is having a relative epic cold snap, colder than anticipated temps, winds, frost bite warnings.. thursday this week it might be the same temp in fairbanks, ak as it will be at my dads house in sarasota.

When you are looking at trees that grow near you, there is nothing wrong with focusing on the high btu stuff - except those tend to have long coaling stages. In cold "enough" weather long coaling stages arent helpful.

Gotcha, thanks. I didn't take what you said as "casting stones". It was new information for me, and so reading it was kind of a lightbulb moment for me. I'm dealing with the cold snap you mentioned, and needing to load at least three times, if not four, per day. That makes coals a pain, and so a short coaling period would be very helpful. Unfortunately I don't have any softwood, but I will have to collect some for next year. Thanks for the tip!

 

[Poindexter]

Gotcha, thanks. I didn't take what you said as "casting stones". It was new information for me, and so reading it was kind of a lightbulb moment for me. I'm dealing with the cold snap you mentioned, and needing to load at least three times, if not four, per day. That makes coals a pain, and so a short coaling period would be very helpful. Unfortunately I don't have any softwood, but I will have to collect some for next year. Thanks for the tip!

Exactly. In cold "enough" weather I load 3-4x daily too. Short coaling period is very helpful for that.

 

[EatenByLimestone]

I start cutting air back when the flame starts licking the baffle. When the flames are strong again, I cut it back some more.

 

[woodsHAM]

As mentioned i get roughly 2-3 hours of secondary burn on my nc30 and it cruises at 650-700. I load it up at 10pm before bed and always have enough coals to get a fire going when im up at 6. Hard maple and bone dry hickory seems to give me the longest lasting secondaries but leave an unmanageable pile of coals in weather like this. Since im off on vacation and its extremely cold ive been keeping the house up to 83 on the first floor by adding 2-3 pieces of oak or ash running the stoves draft wide open and loading at most 4 hrs later. Stove stays around 600-650 like this and burns the coals down well for a good firebox full of wood at bed.