How much flame with air closed down?

[ClubbyG]

Hello All,

I keep reading posts with many folks being able to close the air down on their woodstoves to around 80-90% . I have been getting some pretty good burns with my RSF Opel II, but if I close down the air more than 30% overnight, I don't get many flames and I wake up to very hazy glass doors. I figure dirty doors = dirty chimney.

Just curious if I should expect to see a good amount of flames with air closed down or if I should only expect a 'cigar burn' ? I know a good rule of thumb is that you want little to no smoke coming out of chimney regardless, but wondering how the fire looks for others when air is closed more than 50% ?

think i am still searching for that elusive truly seasoned cord....

thnx!

 

[SlyFerret]

Everybody's setup will be different.

I never shut my air all the way down. I've found that my stove cruises with the air set at what I imagine to be about 25%. Over time, you'll find the right spot for your air control. That spot will change with temperature and pressure changes throughout the burning season.

Wood with a little more moisture than is ideal will also require a little more air than a load of perfectly seasoned wood.

I close my air down to where I get a balanace of good strong secondaries, with some flame still on the wood.

My glass stays pretty clean. I've wiped it down a few times this season with a wet paper towel when company was coming over, but for the most part, the glass stays clear and the firebrick stays nice and tan.

-SF

 

[Highbeam]

I know it seems weird but I get the most flames in the firebox with the air control completely shut after a good char. You've got to shut it to zero in stages or you will snuff the fire. The huge ghostflame show will last until the wood load has given up all of its easy gas. And then in the next stage I get a firebox with no flame from the wood but the roof of the firebox is spewing flames. Then in the next stage it is glowing red wood.

Air control at zero isn't really at zero on a non-cat EPA stove. The intake is still partially open on all of them. I have found through experience that my stove will not overfire with the air control at zero so that's where I put it when I am going to sleep or when leaving the home.

In the morning I have coals only, light brown firebox walls, and crystal clear glass. Ready to stir and restart.

 

[Chettt]

If I have a good bed of coals, I load it full and shut it all the way down, all at once. Since I'm going to bed, high heat that first hour isn't important but longer burn times are. The glass does haze over by morning. I've never snuffed out a flame unless I close down a new fire in a cold stove/flue.

 

[ClubbyG]

Great Stuff!

thanks!

Is it safe to say that you all are burning wood that has been seasoned a year or more? I've only been able to get my hands on wood that is 4-6 months seasoned thus far...

 

[LLigetfa]

My air control doesn't have any numbers, just five positions marked on a label and the control can go below the first mark and above the last. Also, on the Onyx, it is a bi-metal thermostatic control so ultimately, the amount of air depends on the temp. The butterfly is also notched so it cannot be closed completely. I slide the control to the first mark for overnight and yes, there may at times be some haze form on the glass. The door air wash is fed from the same control so it stands to reason that less air will not keep the glass as clean.

Most other times, I run the stove on the second mark. I find that opening it up more doesn't put more heat into the room, just more heat up the chimney. I do however open it up in the morning to burn off the glass and clean the chimney. I also open it wide for about half an hour to get a good char going after stoking it up for the night.

 

[woodjack]

If I close my damper more than 80-90% it snuffs out my fire. I thought maybe my wood wasn't good or I was damping down too soon. I figured all good wood burners closed their dampers all the way. Now I realize that's not the case.

When I close the damper 80-90% for overnight burns using huge chunks it blackens the window. I guess it's not burning as hot as it should, but I get a long, steady burn. I hope I'm not building up creosote on those overnight burns.

 

[rphurley]

Great Stuff!

thanks!

Is it safe to say that you all are burning wood that has been seasoned a year or more? I've only been able to get my hands on wood that is 4-6 months seasoned thus far...

I know that there are all different kinds of wood out there. Here I have primarilly oak and hickory and I find that ideally it should season for two years. That way all of the splits and rounds are perfectly seasoned. I know it is difficult to get three years ahead and not eveyone has the place to store it but in my opinion you should strive to be at least one year ahead with your wood supply.

 

[LLigetfa]

When I close the damper 80-90% for overnight burns using huge chunks it blackens the window...
I hope I'm not building up creosote on those overnight burns.

A haze is one thing but blackened glass is never a good sign. One can burn less-than-ideal wood by giving it more air but unless you keep up the flue temps all the way to the cap, you WILL be building up creosote.

 

[Backwoods Savage]

Great Stuff!

thanks!

Is it safe to say that you all are burning wood that has been seasoned a year or more? I've only been able to get my hands on wood that is 4-6 months seasoned thus far...

ClubbyG, when you get to the point where you have year or two year seasoned wood you probably won't believe just how much different you stove will operate. On top of that, you will get more heat and use less wood. Hopefully you can be there by next year. Even if you can get all of next year's wood done by April you will see a big difference.

 

[gyrfalcon]

Great Stuff!

thanks!

Is it safe to say that you all are burning wood that has been seasoned a year or more? I've only been able to get my hands on wood that is 4-6 months seasoned thus far...

Also depends a lot on the definition of "seasoned." If it was cut, split down well and stacked in full sun and air, 4-6 months isn't that bad, though longer would be better But some folks will try to tell you that trees that were cut down 6 months ago and left lying on the ground in the woods and only cut and split to order just before they bring it to you is "seasoned" six months. It isn't. It's basically still green wood.

Every stove is different, but for whatever it's worth, if I get a full load burning well, I can close the primary all the way and see no difference whatsoever in the fire or the stove temp.

 

[savageactor7]

Takes awhile to really get the hang of it ClubbyG with our QF4300 the most I've choked the primary air is a third. With that I still get enough flames to burn right about 450-500 and that's about the lowest I'll tolerate with a full load of wood.

Of course the blower will lower the stove top temp but with experience you'll get better ID-ing a low burning fire load as opposed to a smoldering creosote producing load. The low burning load will just leave a light ash covering on the glass that real easily wiped off.

There is no easy way to tell you where the sweet spot is...after a lot of trial and error it just arrives and then you'll know what to do.

 

[BrotherBart]

Takes awhile to really get the hang of it ClubbyG with our QF4300 the most I've choked the primary air is a third. With that I still get enough flames to burn right about 450-500 and that's about the lowest I'll tolerate with a full load of wood.

Of course the blower will lower the stove top temp but with experience you'll get better ID-ing a low burning fire load as opposed to a smoldering creosote producing load. The low burning load will just leave a light ash covering on the glass that real easily wiped off.

There is no easy way to tell you where the sweet spot is...after a lot of trial and error it just arrives and then you'll know what to do.

How long does a load maintain around 400 degrees running that stove that way?

 

[savageactor7]

Hi Bart, in short 500* is 2 1/2hrs+ maple/ash fire and 3+hrs for apple cherry fire...although I've never officially clocked it.

If we load fully for an overnight burn on an established bed of coals I guessing 2 1/2 hrs in my target temp zone.

After that the stove top temp will on a maple/ash fire drop to 400 or slightly below but still in the upper grey zone. Then I don't care about lower than target temp because I'm not producing creosote and those remaining shrunken like log husks...like big coals put out adequate heat.

But because I'm get up for other non stove reasons it's not a nuisance for me to add a few more splits right on top of those husk like log remnants without doing jack to primary that still at 1/3rd choke.

On occasion I've observed a +500* 3+ hrs after loading but that's an apple cherry mix. If we're in the house the stove will put out adequate heat for 5-6 hrs. but that's' a night burn.

Since I now better under stand and appreciate the blower the new goal is to choke down as much as possible and still maintain a working fire with blower...and that's about 1 third.

 

[ClubbyG]

Great Stuff!

thanks!

Is it safe to say that you all are burning wood that has been seasoned a year or more? I've only been able to get my hands on wood that is 4-6 months seasoned thus far...

ClubbyG, when you get to the point where you have year or two year seasoned wood you probably won't believe just how much different you stove will operate. On top of that, you will get more heat and use less wood. Hopefully you can be there by next year. Even if you can get all of next year's wood done by April you will see a big difference.

Man this forum rocks...I've learned so much here. Thanks for the replies all. I was over at my stepdad's today and I grabbed just a few logs of what I knew was some prime seasoned dry wood and tossed it in...pure bliss and lively flames

I have to laugh... 'hey pop, can I steal a few logs just to see what really seasoned wood will do in my woodstove?' He gave me an awkward glance but obliged all the same after I explained my quest. (Oddly enough, I used to help him cut firewood but never knew what was delivered when or which batch was which, etc.)

I am starting to get the hang of that elusive charring cycle and am of course now obsessed with that perfect burn. I've felled a few decent-sized trees in the backyard and am already waiting for next winter...


Viva Wood heat!

 

[chunkyal]

I've found that the closed damper burn intensity depends mostly on the outside temperature. At about 0 C fully closed will bring it down to a dirty smolder (but little or no unburnt wood in the morning). At -20C a closed damper can burn 400C +. I think my moderately long (26') single wall pipe exaggerates the temp change. I burn spruce, some seasoned - some not so. After the char they behave pretty similar.