Total creosote clog and CHIMNEY FIRE: THREE WEEKS after brand-new install?!

[branchburner]

Punky wood absorbs moisture very quickly and I find it dries slowly because it's wet inside.

Right, and if you happen to be burning pine that was standing dead, or slab cuts, you quickly discover punkiness is a matter of degree: certainly pine that is cut green and burned the next year will not be at all punky, but pine that is a few years dead is definitely prone to reabsorb moisture even though it doesn't seem to appear that punky.

I don't need to perform any experiments with a moisture meter because I have performed them with my stove. Older mill slabs and standing dead eastern white pine burn great if covered after being split, but sometimes not so great if not covered.

 

[branchburner]

Burning scrap wood isnt an issue either.... mixing it with cord wood is a perfectly fine practice, and is done frequently by many people. Its no different than burning pallets

Right, and can give the same bad results as burning pallets IF done as the OP has done, by closing down the flue damper and air supply to keep them from burning too fast.

I agree, mixing with cord wood is perfectly fine, and is done frequently by me, too, but not 50%. Of course it depend on the stove and the operator, but my experience has been that I had to shut the air back too far, too fast, to keep the fire from running away. Although I don't think wood can be too dry, it can be too small... the excessive surface area meant excessive outgassing at times. My afterburner got overwhelmed, and I ended up with some dirty, smoky burns and even some backpuffing.

 

[ailanthus]

I've heard all that pitch in pine will plug up your chimney and causes chimney fires out East. You may have to move out West here if you want to continue burning pine, no such rumor exist out here.

LOL, it's because of the eastern humidity

 

[Oldman47]

LOL, it's because of the eastern humidity

You have got to be kidding. Lumber-Jack lives in the Pacific North Wet. They burn soft woods because that is what grows there.

 

[ailanthus]

You have got to be kidding. Lumber-Jack lives in the Pacific North Wet. They burn soft woods because that is what grows there.

Yes, I was kidding, thus the 'LOL' and the winky face. Also, I was jesting about the suggestion the original poster's installer made about indoor humidity causing his chimney to plug up in 3 weeks.

 

[Stubborn Dutchman]

I think we might have scared him.

Maybe just out frantically looking for some decent wood to burn!

 

[Jags]

I think we might have scared him.

Nope - not yet at least. He/she hasn't been back since the original posting.
And I really hope the OP doesn't get scared away. Lots of people here willing to help get this wonderful stove operating as it should be.

 

[Toba Guy]

Ok. First off, thank you all for your input, it has been very helpful and appreciated. I am very happy I found these forums.

So, it has been a busy week at work and I've had little time to reply, so thank you for waiting for this, here's what I've got:

- Yes, I had a stove-top thermometer, and it was generally in the "burn zone" indicated (125-325 Celsius, or 275-575 F for my American friends). Though I will admit that my primary focus during those 3 weeks was on keeping the flames blue. Sales rep had told me that was what I was shooting for, that so long as the flames were blue, then gases and particulate was being burnt. This often involved having the flue-damper at least 50% closed, with air intake damper on minimum.

- Yes, the glass was smoking up daily, but would be cleaned off by the heat of the first fire of the day.

- When the installer came to have a look, he removed the flue-damper.

- Had the chimney and flue cleaned professionally. He said he couldn't believe how much creosote their was, over an inch on the inside of the pipe. But to his mind, the real problem was the pest-screen on the cap: it was essentially 100% plugged, way worse than the chimney. He says he has seen this problem before. He removed the screen. He also said he saw no evidence of a chimney fire. He then did a test-fire, and saw that black-smoke was visible from the chimney (I don't know if he got the stove up to temp before looking), and told us that our wood must be soaking wet, and that was likely the real issue.

- Got a wood moisture meter (accurate to within 1%), and tested 8 pieces of pine, on a freshly split face: 9 - 12 % moisture.

I'm going to try getting the stove up to temp and putting the pine on and seeing if black-smoke is visible from the chimney.


Hope this helps and gets your diagnostic minds whirring,
Thank you again for your help.

 

[Jags]

Welcome back. 9-12% humidity seems quite low. Is this air dried fuel? Was it tested at room temps? If frozen it will not read correctly.
Anything below ~400F during the active stage (before coaling) - is too low. Smoking up the window is a sure sign of that. The glass may clear up with the next fire, but your stack isn't gonna see anywhere near those kind of temps to "clean" it up.
Ignore the ranges on your thermo - they where designed for a surface stack temp thermo - not stovetop.

Try this:
Leave your stack damper full open for this entire test. Load stove FULL of wood. Ignite. Primary (left to right slide) full open (to the left). Startup air full open (pushed in). Allow stovetop to come to 400F and close startup air (if it is not the ACC version and automatic) This means pull the push/pull slide full out. Allow stovetop to rise to 550-600F and close primary air full off, then open a pinch back up, maybe 5-10% open and monitor. If stove continues to rise in temps close the primary a bit more. When stove temp becomes stable - smile.
Don't go by "blue flames" or any other visual sites other than the thermo. Keep stovetop south of 750F and it will be a happy camper for many, many years.

Here is what I would expect you to see. Smoke from stack until stovetop gets north of 400F and possibly even up to 500F. After that - no smoke. No smoked up window and a nice fire and more than likely - more heat than you have ever produced from the stove.

Report back. (reporting back with your results is important. It will be very telling if you get different results from the test above. It WILL help us figure out what is going on if you are not successful with the above test.)

 

[Oldman47]

Jags, why are you suggesting that they ignore flame color? I really want to know because I ran industrial boilers for several years and flame color was our primary indication of how well our boilers were operating. A blue flame showed plenty of excess O2 and would lead to almost no visible smoke. An orange flame was O2 deficient and almost guaranteed a dark smoky flue.

 

[Jags]

This is for testing purposes.

I don't know anything about the boilers you ran, but the reburn technology on these stove have people looking for all sorts of "wild rabbit" results. Gotta have rolling flames, gotta see ghost flames, gotta see glowing embers with flame at the top of the box, etc. etc. Half of that comes from "which 10 minutes" were you looking at the stove. Temps don't lie and I know this stove very, very well. If the OP runs the stove as I suggested above - and is successful with that run, I know what the results to the stove and burn will be.

 

[Oldman47]

I can accept that the secondaries were nothing I had to deal with back then. I really wanted to know for my own information.

 

[Wood Duck]

I don't agree with the idea that having nothing but blue flames mean you're burning correctly. Yes, you should have some blue flame at the top of the firebox, but you also need some yellow flames coming from the wood, at least until the load of wood is thoroughly hot. I have four year old oak firewood that burns great, but I usually can't get the stove to burn with only blue secondary flame for more than a short portion of the burn cycle. Most of the time I need enough air to produce yellow flames until the wood is reduced to charcoal (you can't get yellow flames from charcoal).

If the glass is covered in soot, you need more air.

 

[maple1]

Jags - could the type of thermometer he's using be a factor? Can the OP post a pic of it & it's location?

 

[Jags]

I can accept that the secondaries were nothing I had to deal with back then.

We see lots of posts about "can't get my secondary tubes to light off". The idea that there has to be active flame there for it to be working is flawed.

 

[Jags]

Jags - could the type of thermometer he's using be a factor?

Sure - the one he is using is meant for stove pipe. You can tell by the range of temps that are being reported. That is why I suggested above to not pay attention to the ranges but actually go by the temp readings. This, of course, is assuming that the thermo is somewhat accurate to begin with.

OH - and for the Isle Royal thermo placement - I use the top left corner of the griddle area.

 

[Toba Guy]

Thanks for the help Jags.

Forgot to mention, that before the flue was cleaned, the installer came and removed the flue-damper. So that is no longer part of the equation.

The wood is air-dried, and was at room temperature for a week before the moisture-meter reading. Does this mean I have extremely dry wood, or a faulty moisture-meter? It is a digital one, from Lee Valley Tools, Chesnut tools brand.

Did the test you suggested, here were the results:

- during start-up, could feel the negative pressure establish itself (subtle pressure on my head), the furnace was running at the same time. So I opened the window next to the stove wide-open through-out. This also noticeably increased the draft as well. (We're in the process of getting a separate combustion air for the furnace, and fresh-air intake for the basement).

- followed your instructions exactly, once it was up to 600 F turned the primary air all the way down, then back up 5-10%, it continued to climb, so I took it down to absolute minimum on the primary air, it stabilized at 700 F.

- thick black smoke at 400, 500, 600, 650 F: so now I'm questioning either the thermometer or the wood. Does placement of the thermometer matter? I've got it on the stove-top, between the top-loading door and the pipe.


Thanks again.

 

[Oldman47]

Did you split that wood before taking a moisture reading?

 

[Toba Guy]

Just saw your post regarding

Did you split that wood before taking a moisture reading?

Sure did.

 

[bholler]

9% to 12% is pretty low for air dried wood i would question the meter or the testing procedure. Actual moisture levels that low are not impossible but not very likely. Also thermometer placement matters allot and they can be off as well

 

[HarmanManP43]

Pick up some overpriced kiln dried wood from your local store and repeat the test.

 

[maple1]

There is a link to chart somewhere on the site, whereby you can measure resistance through the wood with an ohm meter, then convert the resistance to a %MC value. Might be good for verifying your moisture meter readings.

 

[branchburner]

and tested 8 pieces of pine, on a freshly split face: 9 - 12 % moisture

This would be consistent with the idea that very dry wood ALONG WITH small sizes of that wood, with lots of exposed surface area, could be causing more outgassing and smoke production than can be handled by the secondary burn system.

If that was the case, stove temps might appear to be ok for burning smoke even though smoke wasn't fully being burned.

Personally, I prefer to rely on flue temps (and of course the visual indicator of no smoke) to ensure the burn is clean. Stove top doesn't always give me useful info.(Of course, I run a downdraft stove, so it easy for me to see the stove top run over 500f while the burn chamber is 300f, and obviously not burning smoke... or to have the top run under 500f even as the flue pushes 1000f.)

 

[markam]

This would be consistent with the idea that very dry wood ALONG WITH small sizes of that wood, with lots of exposed surface area, could be causing more outgassing and smoke production than can be handled by the secondary burn system.

If that was the case, stove temps might appear to be ok for burning smoke even though smoke wasn't fully being burned.

Personally, I prefer to rely on flue temps (and of course the visual indicator of no smoke) to ensure the burn is clean. Stove top doesn't always give me useful info.(Of course, I run a downdraft stove, so it easy for me to see the stove top run over 500f while the burn chamber is 300f, and obviously not burning smoke... or to have the top run under 500f even as the flue pushes 1000f.)

I second the theory of excess gas which then condenses. I have had instances where I put one particularly good split in and my entire firebox is on fire from the amount of gas released (even with air turned to minimum. Try running a very small load in your stove and see how it works

 

[Jags]

Okay - a couple of things. First - yes placement of the thermo DOES matter. You are measuring at the very hottest spot on the stove. That is not a bad thing, but for this test I need it to be a familiar zone to me. That zone is the top left corner of the griddle. Second - man is that wood dry, if in fact your meter and procedure is accurate. What size is the average stick of wood? As Branchburner was pointing out - too small of wood can actually cause a massive outgassing that the reburn tubes simply can't consume - the result is smoke.

Any way to confirm the thermo accuracy. Stick it to the wall of your oven at 450F??

We will get this figured out, just stick with us.