Creosote

[Dunadan]

From my sig you can see when I installed the new insert. We've been burning it near 24*7 since. Obviously with some down time to clean out ashes.

This weekend I went up on the roof to have a look down my chimney. Our chimney has 3 flues, with the middle being for the insert. The installer did not need to modify my chimney cover, it's a large rectangular piece of sheet metal, with a heavy chicken wire type screen surrounding the outside (think of a box with solid top and wire sides sitting over the top of the chimney). The insert flue is fully lined with a stainless steel liner and the top of the liner ends about 1" below the solid chimney sheet.

The first thing I noticed was around the edge of the top of the liner, there was a heavy black crust. Not enough to prevent smoke from getting out, but very noticeable. Down the sides of the liner that sticks up out of the chimney, more black crust was pooled up. It almost looked like someone took a can of whip cream, sprayed it along the top edge of the liner, and then let it ooze down the sides. Looking down into the top of the liner I could see some of the same build up, but nothing very heavy. Unfortunately I forgot to bring up a flash light (rookie mistake) and it was so cold I wasn't climbing back down to get one.

Does this sound normal? Obviously when smoke is coming out the top, if it hits a cold surface like the flat of the metal cap I would assume it would cool. I assume this is part of the problem.

Normally we burn the stove hot when we are home, but turn it down to a lower burn during the day and at night to get a nice long burn. I've been pretty happy with my wood burn. It hasn't seemed to be unseasoned, and I did get it from someone who was very well spoken of.

Could there not be enough space between the top of my liner and the cap surface? I would have expected more than 1" of space, but what do I know.

Also, I know there has been a lot of talk about chimney fires. Is it possible to have a fire in a SS liner? If there was one, wouldn't it just burn all the way up and be contained by the stainless steel?

 

[Gunner]

Is it dripping around the outside of the liner or the cap?

Caps seem to be creosote magnets for some and not for others. Some are cleaning plugged caps twice a season.

 

[Highbeam]

So the tubular liner almost, save 1", butts up against the cap? Not good, that is a major draft slower downer. I would expect several inches and at least 4 inches of gapiosis with more being better.

There can certainly be a chimney fire within a liner. Some liners claim to be able to survive certain chimney fires but I would not blow off maintenance just because the liner may survive. The boiling molten tar which is on fire can spill out of the chimney and light the roof on fire.

 

[BrotherBart]

Is it dripping around the outside of the liner or the cap?

Caps seem to be creosote magnets for some and not for others. Some are cleaning plugged caps twice a season.

I think a lot of it has to do with cap design. Lot of those out there with spark screens. Neither of mine have them. I have been up a couple of times to check the flues since it is two new stoves and two new liners this season. I took the caps off and smacked them against the side of the chimney to knock the sote out of them but the openings in them are so big there wasn't any clogging issues in the offing. I could see if they had screens in them where they would probably need attention once a month. I am on top of the hill so they stick up in the wind 24/7/365. I am thinking about just taking the damn things off next season.

Both pipes just had fine brown soot. After the ice storm is over I am going to check again. I am now doing lower, slower burns and want to see the result. Both pipes will probably be full of crap.

 

[Hogwildz]

From my sig you can see when I installed the new insert. We've been burning it near 24*7 since. Obviously with some down time to clean out ashes.

This weekend I went up on the roof to have a look down my chimney. Our chimney has 3 flues, with the middle being for the insert. The installer did not need to modify my chimney cover, it's a large rectangular piece of sheet metal, with a heavy chicken wire type screen surrounding the outside (think of a box with solid top and wire sides sitting over the top of the chimney). The insert flue is fully lined with a stainless steel liner and the top of the liner ends about 1" below the solid chimney sheet.
I am a lil confused. Does the liner extend past the masonry chimney? Is there a top plate around the liner, and if so is it sealed to the liner & masonry?

The first thing I noticed was around the edge of the top of the liner, there was a heavy black crust. Not enough to prevent smoke from getting out, but very noticeable. Down the sides of the liner that sticks up out of the chimney, more black crust was pooled up. It almost looked like someone took a can of whip cream, sprayed it along the top edge of the liner, and then let it ooze down the sides. Looking down into the top of the liner I could see some of the same build up, but nothing very heavy. Unfortunately I forgot to bring up a flash light (rookie mistake) and it was so cold I wasn't climbing back down to get one.

Does this sound normal? Obviously when smoke is coming out the top, if it hits a cold surface like the flat of the metal cap I would assume it would cool. I assume this is part of the problem.
You will have more creoaote build up at the top, especially where the liner comes out of the masonry. It cools off considerably and hence, creosote & also the cap with get built up of creosote. Normal.

Normally we burn the stove hot when we are home, but turn it down to a lower burn during the day and at night to get a nice long burn. I've been pretty happy with my wood burn. It hasn't seemed to be unseasoned, and I did get it from someone who was very well spoken of.

Could there not be enough space between the top of my liner and the cap surface? I would have expected more than 1" of space, but what do I know.
1" from liner end to cap? Seems a tad close to me, I would think it would inhibit draft also, which may be part of your creosote build up.

Also, I know there has been a lot of talk about chimney fires. Is it possible to have a fire in a SS liner? If there was one, wouldn't it just burn all the way up and be contained by the stainless steel?

Yes its possible. Depends how long & hot it burns if it would do any damage. Is your liner insulated?

 

[Dunadan]

The liner extends about 4" past the top of the flue and there is a cover plate over the flue covering the open area. It "appears" to have dripped down the sider of the liner, though I don't think it actually dripped. I think it has just pooled around the the base of the liner where it exits the cover plate.

The actually "cap" sits above all 3 flues and has no apparent buildup. It's like the smoke exits, only has 1" (tops) before it hits the underside of the cap, and then cools and falls down to accumulate on top of the flue cover plate.

I had told the installer if he needed to cut a whole in the cap to extend the liner up more that was fine, but he said there was room to make it fit. I was surprised when I got up there and didn't see more room.

If I need to correct this, is there a good type of cap I can get that will go on top of the liner that's extended out? I also have to be aware of the other two flues coming out. One is used by our boiler and is active, the other by our lower stairs fireplace which is never used. These are oval shaped clay flues. Suggestions on caps for those are welcome too.

As for the chimney fire. Hot bubbling tar spilling over onto roof paints a vivid picture. Point well taken.

 

[Hogwildz]

You def need more clearance at the top of the liner. Is the liner rigid or flex? Most liner manufacturers prrolly want you to use thier components to keep warranty intack. Not sure on that though.
What diameter is the s.s. liner? is it round or oval? You may be able to find a cap with a long neck on it or add a section of liner and cut a hole in the original cap that covers all three flues.Then extent the new cap through that and connect to the s.s. liner or liner extenion.
Or get a cap for each flue. Or custom make a cap with a taller top.
If your handy I would think fabing a new taller cap setup would be easiest way.

Some photos would be real helpful.

 

[jabush]

I'm pretty sure I've read (on this very forum) that the liner should extend 2 inchs past the last flu tile. If your liner sticks out 4 inches beyond the last flu tile, take a pair of tin snips and cut the liner down 2 inches. This will give you a little more exhaust clearance and will most likely improve the situation.

The guys that lined my chimney left my liner a little "long" as well. I've been meaning to cut it down to the 2 inch mark as I also get the "fluffy" buildup in the top 1-2 inches of the liner. The next time I sweep I will cut it back to 2 inches.

 

[elkimmeg]

I want to adress this issue a cap covering 3 flues is far worst than no cap at all. what it does is inpeded the natural upward movement of exhaust. I willing to bet you ccan dmell smoke from your stove near your burner the smoke gets traped under the common cap and the reverse flowof colder air will draw it downward your insert should have at least 9" of separation distance from adjacent flues and not share a common cap. You are posting here about concerns and you hqave the very conditions that develope your worst frears or concerns one inch from the top of the cap. Excuse me but your installrers were they named moe lary or curly. I can't believe they installed a setup like yours. your liner should have a proper termination cap with separation distance. I know Moe Lary and Vurly have not read a code book in a while but common sense shoild have told them this is not a good setup. Does any installer read the installation manuals ? or is it up to the owner of inspectors to read it to them? I am willing to bet there is no mention that this is an acepted practice in the li8ners manual. Forget cuttong it read the liner manual and get the listed termonation cap before the FD visits you home