Chimney smoke at lowest air intake setting?

[John_M]

Been doing a lot of burning 24/7 these days and here is what I notice on my new stove: Air intake full open gives no smoke but I can see some distorted air waves coming from the chimney; air intake half open gives the same results whether the stove has an established fire or after adding new wood to an established fire. Once I close the air intake below about 1/2 open I begin to notice small amounts of smoke. The smoke increases slightly as I close the intake further. When the air intake is fully closed (as far as allowed) I get some smoke even if the fire box is all red embers.

All of the wood is from a 55 year old ash which started dying about 10 years ago and finally stood all dead in my yard for about two years. The tree was felled, cut and split this spring. The approx. 4 cords of wood (1/3 rounds and 2/3 splits) have been stored on open racks 6" off a concrete patio under a 10' roof overhang. The wood gets lots of sun and wind with some rain. It appears to be adequetly seasoned for burning (striking two pieces together sounds like two baseball bats being struck).

Total length of chimney is 18.5' straight run from top of chimney to bottom of stove's fire box and it draws very well.

For two reasons I am concerned about the little smoke visible at the lowest intake setting: 1) environmental pollution; 2) creosote build-up in the chimney and at the chimney cap's screen. For physical reasons I am unable to get up on the roof to inspect the chimney cap but from the ground it appears discolored (black). However, I can see clear blue skies through the screen.

1) Does this amount of smoke seem normal? 2) Do you think the wood is not properly seasoned and could therefore be the cause of the apparent problem?

Should I sit and worry about this "problem" or should I sit and enjoy the warmth and glow of the new stove?

Best Wishes,

John_M

 

[Backwoods Savage]

Sit and enjoy.

Your wood should be fine and it does not sound as if you are getting excess smoke.

As for the chimney cap with screen, most folks remove the screen or at least put in a screen with bigger mesh, like an inch. The cap is where any creosote will form first because that is where the smoke and gasses cools the most. Expect it to turn black but if that screen clogs, you have to clean it. A wire brush does wonders. I still feel it is better without the screen.

 

[BrotherBart]

No sin in having the primary air open a little bit. Lots of folks burn all year long only shutting the primary down around 75%. I shaved one of them this morning.

 

[cmonSTART]

Like BB said, the most I ever shut mine down is about 75%. Anything lower kills the fire. It sounds like your stove is doing what it should. Just find the sweet spot where it burns long and clean and you're golden.

 

[Pagey]

I have yet to be able to close my primary all the way and avoid smoke/killing the secondary burn. I just leave it on that sweet spot like others have suggested. Then it's only heat waves and a clean chimney, even if I do sacrifice a little burn time.

 

[BrotherBart]

A common misconception is that if there are a lot of flames you are wasting your wood. You aren't. You are turning it into heat instead of smoke. And you can test it. Do it both ways and the wood lasts the same amount of time. With less heat choked down.

Wide open is a different story.

 

[Pagey]

A common misconception is that if there are a lot of flames you are wasting your wood. You aren't. You are turning it into heat instead of smoke. And you can test it. Do it both ways and the wood lasts the same amount of time. With less heat choked down.

Wide open is a different story.

Good point, BB.

 

[Backwoods Savage]

But a warning to others: What Brother Bart posted above does not stand for all stoves. Let's not burn our houses down trying to prove a point. I can see it all now: I get flames only when the draft is wide open. So the guy leaves the house with the draft wide open. Whoa! Danger in the making.

 

[YZF1R]

As cmonSTART said: "Just find the sweet spot where it burns long and clean and you’re golden."

I happen to be able to burn mine with the primary closed and no smoke, but that's my insert with my wood. My insert with different wood or my wood with a different insert could easily be different. I agree with cmonSTART.

Steve

 

[paulie]

Yes, you are so right there YZ, every stove is just a little bit different and wood certianly is. Find that spot John and go with it !

 

[BrotherBart]

But a warning to others: What Brother Bart posted above does not stand for all stoves. Let's not burn our houses down trying to prove a point. I can see it all now: I get flames only when the draft is wide open. So the guy leaves the house with the draft wide open. Whoa! Danger in the making.

And something you consistently don't mention in burning advise Backwoods is that you are burning in a cat stove. Which could really lead non-cat EPA stove burners astray. With a cat you don't need flames. With a non-cat the gases are burned in the firebox and you damn sure better have some flames in there to get it done.

 

[John_M]

Thanks, guys. Your comments and suggestions are very reassuring and helpful. Obviously, I am new to burning in the EPA Phase II stoves so these questions will probably come up from time to time. As you suggested, the "sweet spot" in my stove appears to be somewhere between open midway to fully closed. I may have found the "sweet spot" for my stove but didn't call it that. Now I know. The apparent efficiency of a good burn with no smoke at that setting compared to all others is what prompted my Original Post.

Best wishes to all.

John_M

 

[firefighterjake]

Just echoing . . . different stoves, different wood can make a difference. Last year I nearly always had to have the air control open about a quarter to get and maintain good secondaries with little to no smoke coming from the chimney . . . this year with even better wood (cut and split a year prior) I have often been able to shut the air control all the way and get the same effect of good secondary action and little to no smoke.

 

[mike1234]

And ... it sound to me that your wood is not totally seasoned. If you just cut it this spring, even if it was a dead standing tree, it probably is still not 20%. The small limbs are probably ok, and small splits from smaller limbs might be ok, but I would bet the splits from the trunk are still not 20%. Not that you can't burn it, it is just not totally seasoned wood yet, so it will smoke a little more. I have wood from much smaller dead standing trees I cut last winter that is still just above 20%.

 

[Highbeam]

"2) creosote build-up in the chimney and at the chimney cap’s screen. For physical reasons I am unable to get up on the roof to inspect the chimney cap but from the ground it appears discolored (black)."

This bit is going to be your problem. Since you still have that blasted screen in the shimney you can expect to have to make several trips to the roof to clean the cap this year. If that's a problem, as it seems it is, then it needs to be removed. Obviously there are some parts of the country where you can't remove this screen like in the ultra wildfire prone areas of CA due to actual local laws. Look around at your neighbor's masonry chimneys and see how many have extra spark screens. If there are many, and your roof is not cedar shakes then get it removed. You will notice it clogging by the slow draft and smoke puffing into your room from the stove, should take about 6 weeks for cloggage.

I shoot for no smoke but I know that I occasionally get some light blue smoke. If conditions are right though I can get a full burn cycle with no smoke after startup and zero draft setting. I always shut the draft to zero when leaving the house or when going to sleep, never killed the fire yet.