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Wood stove & creosote


Don A

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I have an Ashley side-door wood heater in my basement. I like it for the most part, but sometimes if the conditions are right, the thimble into the chimney will get extremely corroded with creosote. I'm not talking about the brittle, foamy stuff that brushes out easily. This stuff is like black hot-melt glue. When it's cool, you can chip it with a screw-driver. If it gets in the pipe, you can take the pipe outside and burn it out (and it certainly does burn).

However, I have some that has run down my brick work. I have chiseled off a lot of the solid part, but it has left a bad stain.

Any idea what might disolve this stuff? It will be indoors, so I have to be careful about fumes and such. I thought about oven cleaner, but I thought I'd ask first. Figured somebody here would have a trick up their sleeve.

Thanks,

Don

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From my understanding, anything that can break up oil can break up the creosote. Though I'd recommend testing it on a small concealed area before actually making a mess of things, since brick is so porous. You might wind up with many discolored bricks instead of a few isolated spots.

Of more concern to me would be the fact that there is that much creosote buildup. The light foamy stuff is an indication that it's caught fire inside the tube! this can cause a lot of heat very quickly and can last a while(I know you saw that when you burned it outside). I'm sure it's been installed with fire safety in mind. but watch out for that. If you are getting so much buildup that it's dripping back out you must be using very green wood or not burning a very hot fire. The creosote forms when the hot smoke vapors condense on the cold flue(tubing, whatever it's in contact with), this is nothing but unburnt fuel. Same problem exist in the home fireplace, but that's not as easy to see or clean as what you have. I would definitely check how well this heater is functioning, fuel type, etc. All that goo is your money stuck to the walls instead of heating the house. Best time to buy your wood is the spring, and let is cure for the entire summer. Get that thing burning and it can sound like a low flying jet with the amount of air it's trying to suck up the tube.

Sorry if it's a bit of a rant, but i'm a bit cautious when fire and buildings are concerned. Anyway, keep us posted on what you find out.

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I have to agree w/ Candid Q...

DRY WOOD! Let it burn, don't choke your stove down too far. Seal the chimney joints at the thimble--they sell the stuff to do it with at the woodstove or hardware store.

Just be VERY careful!

A chimney fire can get get hot enough to catch your wood framing on fire that is adjacent to a brick chimney! That's danged hot, man!

Creosote is a byproduct of a poor fire...

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When we heated with a woodstove, I tried throwing potato peelings in a fire ... supposed to help break up creosote,(Maybe the moisture helps?) but I'm not sure it really worked. As for stain, not sure what to use. As others said, solvent may just drive stain deeper into brickwork. ?????

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Creosote,
My parents have burned firewood for heat for over twenty years (since they've been married) and the only problem we have ever had was a creosote fire that started at the base of the masonry chimney. Lucky it was encased in ALOT of brick and cement so all it did was smoke up the house quite a bit, but it still warranted the local Fire Department paying a visit. After that dad installed a "catalytic converter" on the stove. I am not sure how exactly it works...but it sits on top of the stove where the stove pipe connects. I believe it somehow collects the creosote before it gets into the chimney and reburns it. I know when the stove is going full blast, the converter has the hottest surface temp on the whole thing.
-Aaron @ the SCF

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Thank you all for the input. We'll try to get things cleaned up and burning this weekend.

And you guys are not joking about the intensity of a creosote chimney fire. Been there and done that in the old days, when my stove chimney had a 6" liner.

Now, my newer chimney has a 12" liner, and it stays clean as a pin. It's only the pipe that gives me trouble. I must confess, I am bad to burn my wood a little too quick (not fully seasoned), and we do choke the stove down to nothing to hold fire over night. No danger of running low on wood this year, so I'll just try to crank it up and feed it more often.

I appreciate it,

Don

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We burn maybe 15 to 20 cords of wood a winter season. The stove is a free standing unit with a 2 foot vertical rise going into a 6 foot horizontal run then into the wall and a chimney. We monitor the exhaust temperature (with a thermometer) as the stove pipe enters the wall and into a masonary chimney. At or below 250*F exhaust temp we get lots of ash problems in the horz run and build up in the chimney. The sweet spot for maintaining low ash in the horz run and little build up in the chimney is 300*F to 400*F. This keeps the house warm. To gain house heat the exhaust temp is raised in incriments from 300*F up to 400*F. Anything above 400*F the additional exhaust temp is wasted heat and just goes up the chimney. These numbers are for this stove in this location only and your mileage may vary.

We burn anything that we can get through the doors of the stove, but try to keep all the wood from the same tree together in the wood pile. Yes it does make a difference. The wet wood from the bottom of the pile is included when the current firewood is "running hot". Blending wood is almost an art form in that respect.

If you monitor the veriables, the outside temperature, the heat output from the stove, the type of wood used, the moisture content of the wood, the exhaust temperature at the chimney, and the build up in the chimney, you can better control the process.

There is lots of smoke when you start a fire, but at operating temperatures, you should see very little smoke from the chimney if you have good combustion. Watch the smoke leaving the chimney as an indicator as to how well the fire is burning in the stove.

Others have answered you question on clean up.

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