Flue damper, and coaling stage....

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
shawneyboy

shawneyboy

Minister of Fire
Oct 5, 2010
1,592
NE PA
So I have a question.

I have a flue damper, not that I need one, but one was installed when the stove was installed. So I was thinking, when my load reaches the coaling stage, no flame, just a big pile of Red coal goodness, I then open up the stove main air inlet some more. This in turn feeds the coals and produces some nice heat for this stage of the burn. BUT>>>>> by opening up the air I am pushing more hot air up the flue. SO ....... If I close down the flue damper this would keep more of the heat in the stove, and not really have an affect on creo build up since most if not all of the gasses are already expelled. This just seems logical to me, but I have not really attempted to use the flue damper for this purpose.

Am I wrong here? Wouldn't opening the intake and closing down the flue make better use of the coals when reaching this stage by keeping the big rock hotter longer ?

If so, well then there is a good reason to have a flue damper when you don't have any over draft situations.

So what do you think ?
 
no respondents... hmmmm lets try a bump.
 
Sorry I did not respond sooner but I was out cutting wood!

Coaling stage, draft gets open full and if you have a damper, that too should be open full. This will get the coals burned down and no, you are not losing all the heat up the chimney at this stage of the burn. We do this all the time; almost every burn. Watching the flue temperature, it stays pretty steady and never shoots up while we enjoy the heat from the stove.
 
I've tried this with my setup and I find that if I close the flue damper down, and leave the primary air open all the way, it acts much like it would if I just left the primary air open only 1/2 way.

Maybe you'd have better luck, certainly can't hurt a thing to try it. I just don't seem to have it benefit my setup. For me, it just slows the draft which means that it slows down how much air is getting sucked into the stove.

However, w/ my old fisher, this method worked really well.

pen
 
That is correct Pen, but you'll have much better luck and do it quicker by opening both full. We have not found any heat loss by doing it and we get the coals burned down so they are not a problem
 
I was just wondering, I guess it makes sense that air wide open and pipe damper closed is like 1/2 open air. I was looking if it would make a difference, not really in burn down but in effective heat retention in the coaling stage. I will try it but benefits may very well be non-existent. Thanks for the input.
 
If you want to retain some heat (not sure how much would be retained), it seems that opening the primary all the way and closing the damper would help. But, as Dennis pointed out, we are often trying to make sure that the coals are manageable by reload and try to add as much air as the stove allows. I've tinkered around with this a little, but not enough to say much about it. Cheers!
 
The coals are red in your stove because they are getting sufficient air to continue the burning process. Closing down the damper at this stage will the decrease the draft somewhat. Those red coals may stop glowing and heat output (granted it it low at this stage anyway) will decrease. You are your own experiment. Give it a try and let us know how it works out. Keep in mind too, that a load of wood only has X Btu's of heat in it. We can burn it hot and fast or slow and long. Really, at the coaling stage there isn't that much draft (in a typical installation). If there isn't that much draft, then you aren't losing that much heat. Also, most (?) of the heat energy produced in the red coaling stage is radiant. The stove steel, glass, stone, or whatever is absorbing direct radiant energy from the coals and then radiating or convecting it out to you.
 
When I experimented with a key damper, in the coaling stage we would see .05" draft on a 32' lined chimney with the damper open. Thats my recommended draft setting for our furnace. So at that point there was no "extra" heat going up the chimney. If that damper was even partially closed the draft was too low and the coals wouldn't burn down with any heat. Once a fresh charge was loaded with an active fire the draft shot over .12" which then closing the damper had to be done to stop all heat from going out the chimney and to avoid a overfire. So in the end its okay to open the damper to burn down the coals. Your draft will be much lower at the coaling stage and in its highest at an active burn.
 
OK well I tried it. Close flue, full open intake. Bah nothing to report. Not a big difference in heat output or anything, back to the "normal" way. Thanks for the input, I just had to ask to see if I was missing something..... to quote Obewan....

"These are not the droids you are looking for.....Move along "
 
Status
Not open for further replies.

Similar threads

30WCF
Key Damper Theory
Replies
44
Views
2K
The Hearth Room - Wood Stoves and Fireplaces
T-Rav
T-Rav
B
1940s Damper Handle Missing
Replies
1
Views
199
The Hearth Room - Wood Stoves and Fireplaces
bholler
B
L
Very large chimney for 6" flue
Replies
6
Views
820
The Hearth Room - Wood Stoves and Fireplaces
Solarguy3500
Solarguy3500
N
Damper and air supply experience and experiment - NC30
Replies
23
Views
2K
SBI: Century,Drolet,Osburn,Valcourt,Englander
weee123
weee123
S
Actuater
Replies
0
Views
240
The Hearth Room - Wood Stoves and Fireplaces
Southwestpaburner
S
Top Bottom
Back