Smoke from the chimney post secondaries - thoughts?

[NH_Wood]

Hi guys and Happy New Year (almost)!

I'm burning dry wood (3 years in the stack). Get great burns with no smoke exiting the chimney during the first 3 or so hours of the burn, when the secondaries are active. As the load begins to coal, I notice that bluish smoke is exiting the chimney. At this point, the wood on either side of the fire box (I load N/S) is mainly intact, just well-charred, and if I move them to the center, they catch flame - the center area of the fire box is hot coals. I assume the smoke is coming from the wood on the edge which is not combusting as well as the center wood.

As some of you know, I don't have the optimal venting scenario - I vent from the stovepipe into a ~ 11" square masonry tile flue that is used for the fireplace (I don't use the fireplace when the stove is running, so essentially, I never use it in cold weather - stove is located on the opposite side of the fireplace, not a fireplace install).

So, thoughts on why I see smoke only when I enter the coaling phase? Stove temp and flue temps still high at the point when I see the smoke. I'm guessing it is an issue related to my setup, and if that's true, I'm not overly concerned - creosote build-up was minimal last year.

Lastly - does this smoke likely lead to minimal creosote in the flue at this point (flue is obviously nice and hot by this point, etc.), or am I likely still getting creosote?

Cheers!

 

[HotCoals]

Come on..EPA tube stoves do not smoke after the gas grill burners die out..I know because I read it here!

J/K

 

[BrotherBart]

Come on..EPA tube stoves do not smoke after the gas grill burners die out..I know because I read it here!

J/K

Yeah right. And cat stoves don't either after the cat goes inactive. Ha!

As to the OP. It is just a matter of a very large firebox and not enough air getting back there to burn the wood. If you are running the stove closed all the way down that is almost guaranteed to happen. The air from the reburn tubes is not aimed down back there. The air has to come from the primary input at the front of the firebox and travel a long way to get back there.

Run with a little more primary air and see what happens. I have a different stove but a large firebox and that primary has never been closed all the way in a burn in six seasons. For exactly that reason.

 

[HotCoals]

Ya..tube guys trying to run their stoves like a cat stove..no flames below..why not just buy a cat stove? lol

I'm telling you that Progress Hybrid is on track..just have to have a way to kill the secondary air when in the shoulder season..I could figure it out..lol.

 

[NH_Wood]

Come on..EPA tube stoves do not smoke after the gas grill burners die out..I know because I read it here!

J/K

Yeah right. And cat stoves don't either after the cat goes inactive. Ha!

As to the OP. It is just a matter of a very large firebox and not enough air getting back there to burn the wood. If you are running the stove closed all the way down that is almost guaranteed to happen. The air from the reburn tubes is not aimed down back there. The air has to come from the primary input at the front of the firebox and travel a long way to get back there.

Run with a little more primary air and see what happens. I have a different stove but a large firebox and that primary has never been closed all the way in a burn in six seasons. For exactly that reason.

Good deal BB - thanks! Makes sense and when this happens I do open the primary to let more air in - I'll try leaving the primary open - perhaps 10% - and see if that helps. Good to know it's a typical thing and not directly related to my non-optimal setup. Cheers!

 

[kingquad]

Come on..EPA tube stoves do not smoke after the gas grill burners die out..I know because I read it here!

J/K

Yeah right. And cat stoves don't either after the cat goes inactive. Ha!

As to the OP. It is just a matter of a very large firebox and not enough air getting back there to burn the wood. If you are running the stove closed all the way down that is almost guaranteed to happen. The air from the reburn tubes is not aimed down back there. The air has to come from the primary input at the front of the firebox and travel a long way to get back there.

Run with a little more primary air and see what happens. I have a different stove but a large firebox and that primary has never been closed all the way in a burn in six seasons. For exactly that reason.

I'm finding this to be the case as well, especially with the milder weather we've been seeing.

 

[fishingpol]

I learned a better burning habit from BeGreen that when the wood goes into the coaling stage, I see stove top temps drop a little on my set up. At this point I open the primary air full, the coals brighten and I extend the burn time a little. About 1/2 hour later, time for a re-load. I've never looked at the pipe outside too see if it smokes at the coaling stage. I'm curious now.

I would think as mentioned above, not enough air at that stage.

 

[rdust]

My Endeavor would smoke later in the burn if I didn't open the primary air up just a touch from fully closed. When I didn't close it down all the way it seemed to be fine. That stove liked to run hot though so I usually always had to close it down to maintain my sanity! The smoke would trail a few feet off the chimney and disappear so it's not like I was smoking out the neighbors. This never lead to any major build up, I just didn't like to see it.

 

[HotCoals]

I don't know how you tube guys keep track of all your diff settings at diff times ..must use excell..I just set the t-stat and walk away!
Of course..I do have a smokey window a lot..aint no fire to see anywho!

BTW...I gota clear this up..my avatar of my stove is before I fired it...I know it looks smokey in the pic..but nope..lol.

 

[rdust]

Yeah right. And cat stoves don't either after the cat goes inactive. Ha!

Up to this point my cat has stayed active up to me needing to reload. Of course it's new this season so as the cat ages it probably won't perform as well.

 

[laynes69]

We get it also in our furnace. It's a 3.5 cu ft firebox so it's a decent firebox. This weather is a killer, it's been too warm. If winter would ever hit, it's not a problem. By the time we hit the coaling stage, the house has dropped below the thermostat on the wall. From here it will open the primary and close it to keep the house at a set temperature keeping a hot coal bed. In the shoulder seasons I build smaller fires. I thought maybe it was me, guess not.

 

[SlyFerret]

It really isn't that complicated. Just lots of overthinking around d here usually.

If we didn't talk shop though... what else would we do? I'd probably just fall asleep on the couch.

-SF

 

[HotCoals]

Yeah right. And cat stoves don't either after the cat goes inactive. Ha!

Up to this point my cat has stayed active up to me needing to reload. Of course it's new this season so as the cat ages it probably won't perform as well.

Rdust,

Don't let that cat probe gauge fool you..it's also picking up the stove top temp.
That said the cat is active on the way down..I don't know how far down..I would think around whatever they say engagement is..400 was it?

 

[BrotherBart]

I think a lot of people burning all kinds of stoves would be surprised if they went out and looked at the end of a long burn. Pretty much all three or four hundred degree stoves with a pile of stuff in the back of the firebox smoke at that time. But it is mostly happening up in the morning while everybody is still asleep and it is dark. Most only pay attention to smoke when they are running out to make sure the stuff coming out of the stack is clear on restarts or reloads.

 

[pen]

Perhaps that large chimney that your stove goes into is not drafting strong enough when the burn goes into later stages and that is why you are lacking air?

As BB mentioned, I'd give it a touch more air.

My stove did this a lot before I lined the chimney.

Now, very seldom and usually only when I turn the air down just a bit too far after having a very large load of wood.

pen

 

[HotCoals]

I think a lot of people burning all kinds of stoves would be surprised if they went out and looked at the end of a long burn. Pretty much all three or four hundred degree stoves with a pile of stuff in the back of the firebox smoke at that time. But it is mostly happening up in the morning while everybody is still asleep and it is dark. Most only pay attention to smoke when they are running out to make sure the stuff coming out of the stack is clear on restarts or reloads.

I concur!

 

[oldspark]

I think a lot of people burning all kinds of stoves would be surprised if they went out and looked at the end of a long burn. Pretty much all three or four hundred degree stoves with a pile of stuff in the back of the firebox smoke at that time. But it is mostly happening up in the morning while everybody is still asleep and it is dark. Most only pay attention to smoke when they are running out to make sure the stuff coming out of the stack is clear on restarts or reloads.

I concur!

Well mine does not, I have been outside on the end of a long burn because we have all this warm weather and am letting the fire go out in the day time a lot and have never seen it smoke at the end of the burn BUT my primary air is not quite all the way closed either

 

[HotCoals]

I think a lot of people burning all kinds of stoves would be surprised if they went out and looked at the end of a long burn. Pretty much all three or four hundred degree stoves with a pile of stuff in the back of the firebox smoke at that time. But it is mostly happening up in the morning while everybody is still asleep and it is dark. Most only pay attention to smoke when they are running out to make sure the stuff coming out of the stack is clear on restarts or reloads.

I concur!

Well mine does not, I have been outside on the end of a long burn because we have all this warm weather and am letting the fire go out in the day time a lot and have never seen it smoke at the end of the burn BUT my primary air is not quite all the way closed either

I have no idea really..I was just trying to fit in with the admins..lol.

 

[oldspark]

I think a lot of people burning all kinds of stoves would be surprised if they went out and looked at the end of a long burn. Pretty much all three or four hundred degree stoves with a pile of stuff in the back of the firebox smoke at that time. But it is mostly happening up in the morning while everybody is still asleep and it is dark. Most only pay attention to smoke when they are running out to make sure the stuff coming out of the stack is clear on restarts or reloads.

I concur!

Well mine does not, I have been outside on the end of a long burn because we have all this warm weather and am letting the fire go out in the day time a lot and have never seen it smoke at the end of the burn BUT my primary air is not quite all the way closed either

I have no idea really..I was just trying to fit in with the admins..lol.

:lol:

 

[Hogwildz]

Lets not hijack the guy's thread.
Comments discouraging secondary burners ain't going to help the guy out.
You already have 2 Kin/cat threads going. Cut these guys some slack already.
Fun is fun, but give it a rest.

 

[HotCoals]

I think we all agree that there will be some smoke some of the time..cat or non cat..pretty much has to be!

 

[tfdchief]

Look at my signature. I have the old and the new. I love heat, efficient burn, less wood, etc. etc., but in 40 years of burning wood, I have found that there will be some smoke ;-P "Where there is smoke there is fire" Keep your flue clean. Never had a problem. Thank God.

 

[NH_Wood]

Perhaps that large chimney that your stove goes into is not drafting strong enough when the burn goes into later stages and that is why you are lacking air?

As BB mentioned, I'd give it a touch more air.

My stove did this a lot before I lined the chimney.

Now, very seldom and usually only when I turn the air down just a bit too far after having a very large load of wood.

pen

Do you think the stove would draft less a few hours into the burn? I figured the draft would be as good as it gets at that point - let me know why the draft might be low at this point in the burn. I will try a touch more air and see if there is a difference. All in all, the stove runs like a champ - just wasn't sure if it was normal to see smoke at this stage in the burn (as BB said, I always looked at the stack as the secondaries were kicking in to see if I was burning clean - I guess I just wasn't looking at the right time to see the smoke. Cheers!

 

[pen]

Do you think the stove would draft less a few hours into the burn? I figured the draft would be as good as it gets at that point - let me know why the draft might be low at this point in the burn. I will try a touch more air and see if there is a difference. All in all, the stove runs like a champ - just wasn't sure if it was normal to see smoke at this stage in the burn (as BB said, I always looked at the stack as the secondaries were kicking in to see if I was burning clean - I guess I just wasn't looking at the right time to see the smoke. Cheers!

As stove pipe temps start to drop so will the chimney temps and your chimney effect (the draft) will diminish. As that happens, the stove can't pull in as much air anymore and the stove starts to smoke a bit since the large coals can't get the air they still need.

Next time you notice that happening just open the air up a bit more, let it ride for about 5 mins then go outside and see if there is any difference in the smoke.

My 30 ran into a 7x7 clay chimney and would do the same thing. It was about this time in the burn that I would start to get some black on the bottom of the glass too. I could get that stove 700+ no problem on the old chimney but once it started to cool down later in the burn the draft dropped quickly and the quality of the burn did as well. W/ the lined chimney I very seldom find that smoke later in the burn and never get black glass unless I turn the air down too far on my own.

Can't remember if this is an exterior or interior chimney. The effect I mentioned would be bigger on an exterior one but w/ the size of that flue I could see it happening even on an interior unit.

But, I'd just play around w/ the air settings for a little while and see what that does for you first. My stove ran fine w/out the liner but runs much more consistently with it.

pen

 

[rdust]

Do you think the stove would draft less a few hours into the burn?

I would think so, as the chimney cools the draft is going to be less which in turn will pull less air through the stove.

With my Endeavor if I was around I'd open the draft some once it started coaling out, if I was at work I didn't care.

Edit: Nevermind Pen beat me to it. :lol: