Coaling Stage. How to get the most out of it?

[prajna101]

Should I give it air? Or shut it down?

It seems if I shut it down it lasts forever and still burns clean. Secondarys are not burning but neither is it smoking.

If I give it air, it glows hotter, but am I just blowing any extra heat out the chimney?

Todd

 

[Slow1]

I look at it as a question of how much heat do you need from the stove. For the most part if you need more heat from the stove, give the coals some air and they will burn faster giving you more heat as they go away, thus getting the stove ready for another load sooner. If you aren't looking to load the stove anytime soon then just leave them alone so they 'last forever' as you say and are there ready to use to start the next load when you are ready for more heat.

I think the issue really comes into play when folks are trying to get more heat out of the stove come mid-winter and coals build to too much. At that point more air to burn them down seems to be the general recommendation. I certainly don't consider coaling stage to be a waste though - a lot of energy is in those coals and you can benefit from making use of them.

 

[EatenByLimestone]

I build as many coals as I can for cold weather all night burns.

Matt

 

[jadm]

How I treat coals depends on temp. in the house and how big the pieces are.

If it is warm enough and I am not going to add more wood, I let them burn down - stirring them and raking them to the front of the firebox so they burn down as much as possible. I usually end up doing this several times.

I adjust the air according to how long I want them to keep burning. Less air and they last a bit longer - more air and they burn a bit faster. (Coals don't smoke. All the gasses that do smoke are generally gone by the time coaling takes place - that is if the coals are on the small side.)

The more air they have, the more efficiently they will burn down and, yes, more heat goes up the chimney.

If the wood I am burning happens to be really hard and the coals are on the bigger side and I want room temp. to stay constant, I will throw in a piece of pine to burn on top of them which helps them burn down and gives more heat then burning them alone. In this case I leave the air at about 1/2 way open.

If it is really cold out and I want a hot fire going - I rake the coals forward and use them to start up another load of wood....

 

[Corey]

Once you have coals, you're essentially burning pure carbon - there are no wood gases, tar, etc which lead to smoke. So, it would seem to reason, since there is no smoke to worry about, the most efficient burn would come from closing the air control down as far as you can but still generate the heat you want. More air would either be making more heat than you need (wasteful) or putting more air up the flue which both cools the firebox and increases the heating requirement for the house as you need to warm up the fresh air coming in.

 

[bluefrier]

Should I give it air? Or shut it down?

It seems if I shut it down it lasts forever and still burns clean. Secondarys are not burning but neither is it smoking.

If I give it air, it glows hotter, but am I just blowing any extra heat out the chimney?

Todd

I've notice the same thing with my stove. It's best to close the air control after the wood gases burn off, most of the heat stays in the stove and the coals last much longer. Open the air control and temps start to drop. A cooling effect from too much air flowing thru the stove and up the chimney? Guess so.

 

[wellbuilt home]

I don't mess with the coals much .
When the stove temp gets to 200o I rake the Cole's to the front and reload .
If the out side temp is 40o I just burn one fire a night and the stove is still 150o after work 20hrs later .

 

[woodgeek]

I have always wondered this--as other have said the no smoke is obvious, but in a lean enough burn coals could still make a ton of CO which, aside from being pollution, is a waste of good fuel. Can anyone answer that concern??

 

[Corey]

If you cut the air too much, the coals can make CO - this would usually be considered a 'rich' burn as you have plenty of fuel, but not enough air. The CO -> CO2 reaction does provide a modest amount of energy but other factors are important as well. 1) Even if the stove is moderately starved for air, you are still producing a lot of CO2 and only a little CO. 2) Excess air cools the stove and also wastes heat as mentioned earlier. Probably the only way to hit the air control dead on would be run an oxygen sensor in the flue and dial in to a stoicheometric air/fuel ratio.

 

[precaud]

When burning down coals, the secondary air is doing nothing except cooling down the stove and exhaust stream. So shut down the secondary air when the flaming part of the burn cycle ends.

 

[par0thead151]

i too am interested in the OP's question.
i have learned how to use my enviro 1700 venice insert very well when wood is burning in it, but the coaling stage nets me very little heat with m particular insert. or at least i believe it is giving me very little heat...
I am finding that i can not burn the coals down as my home gets too cool if i wait till they burn almost all the way out.
i can toss a new set of splits on the fire, but then i develop a thicker bedding of coals and they eventually build up so much as to not allow me to reload the stove.
i have raked the coals to the front of the stove but that too does not net me nearly as much heat as a log would..
is this normal?
i find myself shoveling out the coals that are partially burned(not glowing red, but not carbon black either) so i can reload the stove with wood.

 

[madrone]

If I'm going to be home and want more heat, I pull coals to the front and open the air. If I'm leaving, I leave it closed. If the choice is between "letting heat go up the chimney", or reloading before the coals burn down, then the efficiency argument seems like a wash. You're either choosing to be colder, or use wood faster. I don't like loading on top of too many coals, or being colder when I don't have to.

 

[lobsta1]

When burning down coals, the secondary air is doing nothing except cooling down the stove and exhaust stream. So shut down the secondary air when the flaming part of the burn cycle ends.

I second this. I believe on that my NC13, the amount of air is fixed. Moving the slide only changes the air from the secondary up top to the coals in the bottom. Since the coals give relatively little heat & can build up way to much, as the wood burns down I divert the air to the bottom & burn up the coals. From the amount of ????s about excessive coaling, it seems that many people are NOT diverting the air to the coals. When you have a stove with a small firebox & it's 10 degrees out, you have to try & maximize the heat output. With a big stove you have more options.
Al

 

[rdust]

Like others have said it depends if you want heat or want them to last. It's still pretty warm out so I very seldom want to load the stove when it starts to coal. I start by shutting down the primary air, if I need go longer then I think they'll last with just the air shut down I shovel them into the back corner and cover them with ash.

 

[EJL923]

shut it down. On my stove, the secondary's provide enough air to keep some heat going. The secondary's arent burning, just bringing fresh air to the party

 

[par0thead151]

When burning down coals, the secondary air is doing nothing except cooling down the stove and exhaust stream. So shut down the secondary air when the flaming part of the burn cycle ends.

I second this. I believe on that my NC13, the amount of air is fixed. Moving the slide only changes the air from the secondary up top to the coals in the bottom. Since the coals give relatively little heat & can build up way to much, as the wood burns down I divert the air to the bottom & burn up the coals. From the amount of ????s about excessive coaling, it seems that many people are NOT diverting the air to the coals. When you have a stove with a small firebox & it's 10 degrees out, you have to try & maximize the heat output. With a big stove you have more options.
Al

my stove has one control for the air. which i assume controls the afterburner air supply.
my routine for the stove is to load it full of wood, leave air on high until the entire stove is engulfed in flames, then check it with my IR thermometer.
once the sidewalls read 600-700 i throttle the air supply all the way back.
this will allow my box to burn for 10 hours+ and still have coals to light the next fire.
my problem is not the hot coals, but the cold ones. the black lumps of coal that are no longer burning.
is this something that will build up over the course of a week or two of burning?