Creosote dripping from stove pipe Tee after sweeping

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Piston

Member
Dec 4, 2008
77
Upton, MA
I had my first couple fires of the season this past week in my Woodstock Fireview, which I've owned for 3 years now. Everything was fine, and both my fires burned to my expectation.

Yesterday morning, I lit another fire and kept it going all day. Around 9pm I stoked it up pretty good (the same as I've been doing) gave it about 15mins or so, engaged the cat, and after another 15mins I closed the damper pretty far down, to about a 0.5. The flames were non existent after a couple of mins and I went to bed.

My wife woke me up around midnight saying she smelled smoke. I did too as soon as she woke me up, it smelled like damp creosote. I figured I must have closed the damper down too far so I came downstairs and opened it up a bit. I did smell a decent amount of smoke.

Went back to bed, woke up in the morning and it still smelled a bit, but much less. I stoked up the fire again and got it going really good, I still figured the smell was from damping down the air vent too much.
However, as soon as the stove got good and hot, I noticed some smoke, and a few drops of liquid creosote, seeping through the joint at the end cap of my stove pipe (the cap at the bottom of the liner, where the Tee is).

Here is what it looked like.

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Here is a little more info...

This will be my 3rd year that I've been using this same exact setup. I didn't really do anything different that I can think of.

I have a full length stainless steel liner properly installed.

I swept my chimney last month with the proper poly chimney brush, and got a little over a beer can full of creosote, all in all the chimney still looked pretty clean. It was my first time cleaning this chimney liner after 2 yrs of burning this woodstove (I have learned a lot since then and now know to do it more often).

It was burning fine with no smoke leaking out for the 2 days prior, and burning at the same temps, although I didn't damp it down.

When I cleaned the liner, I couldn't get the last couple feet of the liner, and I did not clean the Tee pipe coming out of the woodstove.

Any ideas why I'm getting this smoke/creosote leak? I was going to take the pipe apart and make sure there is no buildup at the cap.

I'm hesitant to fire up the stove again until I know why this is happening. I was told to "burn it hot, to burn out the creosote that was left over from sweeping" does this sound like sound advice?

Where should I go from here?
 
"burn it hot, to burn out the creosote that was left over from sweeping"

That doesn't seem right, the point of cleaning is to remove everything in the first place.

Like you said dampening it down too much could cause this problem. Try first cleaning everything well. Make sure your wood is dry.

If the liner is not insulated, it will make this problem worse also. But if you said you only got a can of creosote out, either it is insulated and burns very efficiently or there was a lot left over in the liner from the cleaning.
 
Not that this matters but what type of wood were you burning?
 
It appears that when you brushed that chimney you piled a bunch of crud either in the tee or the horizontal pipe. And that slow burn with the cat engaged turned it into liquid creo. Clean that whole system out. Really well. And take a long hard look at how dry your wood supply is.

And I would really like to know what turned that stainless tee snout black. I have NEVER seen that happen. Golden yes from heat but never black.
 
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If the liner is not insulated, it will make this problem worse also. But if you said you only got a can of creosote out, either it is insulated and burns very efficiently or there was a lot left over in the liner from the cleaning.

The liner is not insulated. Does this mean that I should have gotten a lot more creosote out than what I got? I used a poly brush with the fiberglass rods, and cleaned from the top of the chimney down.
I could not get the last couple feet from the top though. Where the stainless liner goes through the flue of my chimney, the liner is "squished" into a slight oval shape, so the brush wouldn't fit through the ovaled section.
I also didn't clean the Tee section coming out of the stove, when I looked into it, it looked very very clean and there really wasn't anything on the inside of that pipe from what I could see.

Tomorrow I will take the pipe apart and be sure to clean it out really well.


Not that this matters but what type of wood were you burning?
It's a combination of ash, red oak, and something else that I don't know what it is.

I really don't know what the moisture content of the wood is. I suppose I should invest in a good moisture reader. Everything has been split and stacked for over a year, however, the ash that I burned last night was still round, so I split it right before putting it in the stove.


It appears that when you brushed that chimney you piled a bunch of crud either in the tee or the horizontal pipe. And that slow burn with the cat engaged turned it into liquid creo.
Before sweeping the chimney, I removed the bottom cleanout cap and put a trash bag over the bottom of the stove pipe, I then taped the trash bag on the pipe. I cleaned the chimney from the top down figuring that all the creosote would fall into the trash bag, that is how I measured the amount I got out.


And I would really like to know what turned that stainless tee snout black. I have NEVER seen that happen.
Should I be concerned? I've always operated my Fireview according to the manual, as well as all the tips I've learned from here.

I do consider myself fairly knowledgable at woodburning, and I don't think I'm making any stupid mistakes with this. I know that my wood could, and should be, drier, however, I know that the wood I've been burning is drier than stuff I burned last year as I wasn't prepared last year, and this has never happened before.

Thanks for the tips...
-Matt
 
The Red Oak can take two years of seasoning, Ash I would let season for a year, could be your wood.
 
Where the stainless liner goes through the flue of my chimney, the liner is "squished" into a slight oval shape, so the brush wouldn't fit through the ovaled section.

Does mean that this section of the liner has never been cleaned? It seems likely that if this is the case that oval part of the liner plus the creosote build up would reduce the draft significantly, causing the creosote build up and leaking out of the bottom. Its a possibility.

To clean the liner in the oval section, well the entire chimney can be cleaned with it, I have used and really like a Sooteater. It is a simple design and very effective. All you need is your drill.

http://www.amazon.com/Gardus-Inc-RC...d=1354068515&sr=8-1-spell&keywords=sootoeater
 
Does mean that this section of the liner has never been cleaned?

Yes, that section has never been cleaned. This year was the first year I've cleaned any of the liner, although now that I'm really thinking about it, I think I installed the liner last year, not when I bought the stove a few yrs ago, it was either last year, or the year before, I'd really need to look back at my receipt, wow, can't believe I don't remember what year that was!
I couldn't wait until tomorrow, and I started taking apart the stove pipe tonight. I took the cap off and sure enough, there was creosote baked into the inside of that cap. I took the Tee section out to the garage, cleaned it up really good, and I'm reinstalling it now. My problem was definitely that creosote buildup in the cap, I'm wondering though, how it got there, and will it happen again.

It seems like it must have been caused by wet wood, since I know I cleaned out the chimney really good, and even now, looking up the liner (even the ovaled out portion passing through the flue) it looks really clean. It's black naturally, but any creosote in there is just a thin layer of a fine dust, there is no buildup at all. Even inside the Tee section there really isn't any buildup, and I didn't even clean that section originally.

I did take some pics and I'll post some once I get this back together and cleaned up. I didn't think any of the wood I was using was that wet, but that is the only explanation. Also, when I opened the top of the stove, there is a series of small creosote "bubbles" that formed on the inside of the stove. I've never seen this before, I've used not-so-seasoned wood before with no issues, but this is something different, I must have gotten a few pieces of really really wet wood somehow. I need to be more careful I suppose.

I'm going to finish putting this back together and try it out tomorrow with some dry wood, and see if I get any of this back. If I make it 3 days of burning with no problems, I'll know the issue has been resolved. Also, instead of cleaning the old cap, I bought a new one from Lowes, not as heavy duty as what was on there, but probably better off anyways.
 
Well I got it all back together. The cap I bought from Lowes wasn't the right size (it was 6" but didn't fit my 6" pipe) so I cleaned up the old one really good and installed that.

As I mentioned, I also had some creosote 'bubbles' on the inside of the stove top, when I flipped the lid up, this is what I saw....
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...and a close up of the corners...

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I scraped these spots off and it was just a paper thin, shiny bubble. They were easy to remove. I'm curious why these small bubbles of creosote form?

I cleaned up the end of the Tee, which had quite a bit of caked on creosote on it...
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Here is the inside of the pipe after cleaning it some more...
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I got all the creosote off the inside and outside of the cap as well.
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Lastly,
Here is a pic of the inside of the liner, this is just past where the liner goes through the flue of the fireplace and causes it to squeeze into an 'oval' shape. I couldn't clean this from the top down, so I figured I'd clean it out now from the bottom, however, it looks so clean as it is, I didn't bother. It really is just a light coating.
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I'll order one of those soot eater things to help me clean this for the next time I do my chimney.

Tomorrow I'll climb up on the roof to make sure there is no creosote build up at the top of the chimney (I can't see how there would be after only 3 days of burning). Then I'll light it up again with some good dry wood and see how it goes. I'll be a little more careful with not damping it down so much, especially if the wood is less than perfect.

My next purchase will be a moisture meter, I'd like a good one that I can be confident in. Anyone have any favorites that they use?
Thanks for all the suggestions so far, hopefully the problem was just some wet wood, I hope. Since that's never happened before, and I have burned similarly wet wood (I believe) I'm a little skeptical, but I'm hoping.
 
I have red oak in a stack that has been two full years, MM says it's still above 20%.. I use a MM I got at HD.. it's "General" brand. I compared it with my neighbors, some other brand, both read the same on a fresh split, so accurate, or just as off as his.. your guess. lol

I think it was about $25..

I also have to say the outside of that T looks odd, like it was oiled before fired or something. I have a couple cookie sheets that are old and look kind of like that.
 
The cleaning of the Tee looks good. This should take care of your issue for now. As you said just make sure your wood is dry and do not damper it down too much for too long.

The tee does look a little odd, being black like that, but I would say as long as it still has it's integrity and strength it is fine.
 
Hey there - Upton eh? I'd say we're only a few miles apart :)

Anyway - I wonder if perhaps you generated all that mess in the one burn. Perhaps you stalled the cat when your turned the air down that far and went to bed not realizing you were churning out cool smoke that then condensed in the lower section of the pipe and/or the back of the stove. Certainly it appears you were dripping some inside the top of the FV there so it does seem likely it was in the pipe too.

Does the horizontal section slope toward the stove or down toward the T? If it is sloping toward the T then the drips would flow that way and collect in that cleanout cap to eventually drip/flow out. It doesn't take a whole lot to make a smell when hot.

A possibility could be that it was smouldering for a while and dripping, then finally the wood dried out enough and it heated up enough to get the cat going - then hot exhaust warmed up the mess in that section allowing it to flow better. If the cap on the cleanout wasn't really tight it would flow out I'm sure. Pure conjecture, but the scenario just might fit...

Once it is all cleaned out and put back together I would pay close attention to how your wood burns when choked down as you did that night - try it during daytime and watch the smoke output for at least the first couple hours after setting the final air. Repeat a few times and you should have a solid feel for it - if you are getting smoke then it isn't right, if it is clean smoke then you shouldn't have anything to make that mess.
 
Slow1,
That explanation sounds exactly what could have happened, when I think about it, that really makes sense. I never thought that maybe I stalled the cat, but that would be a perfect explanation (or at least put my mind at ease anyways:))
I'm gonna light a fire now and see how it goes.
I live real close to Pratt Pond by the way. So if you see a thick black smoked up chimney today when your driving around, swing in for a beer ;lol

I think the picture I took of the pipe may be a little off colored. There isn't any black on the pipe, but there are some discoloration's, not sure what that is from but the pipe is a fairly heavy gauge that I bought from somewhere recommended on here.
 
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