Creosote smell problems

[JAT]

We got a new EPA certified Lopi insert last season. Ever since the new insert was installed (by a certified installer) we have had a BIG problem with smell. The fire draws fine when there is fire going and for 24 hours after we have had a fire everything is fine, but 24-48 hours after the fire has gone out the ENTIRE house (small <1200sq ft house) smells like creosote/smoke. There is NO smoke in the house, the fire has been out for over 24hours at this point. We talked to the dealer, they put a little more insulation around the insert which didn't work.

This started happening last season, the weather warmed up and we had not had a fire from last March/April. Then as soon as the weather turned cooler this past fall, without having had a fire since last spring, the smell returned. We contacted the dealer again and they put us in contact with a chimney sweep/expert to clean everything. He advised us the problem is creosote build up and told us to always burn the fire with dampers open so it will burn hot. This helped some but has not eliminated the problem. He said on a scale of 1-10 our build up was a 2 which doesn't seem like it should be causing this big of an issue.

We need help, at this point if it can't get fixed somehow, the stove will have to be re-sold, we can't live with it this way. We are burning through our wood supply like crazy because even on nights where it's relatively warm and we wouldn't necessarily need a fire we are burning one just to prevent the smell from coming back and trying to keep the fire as hot as possible is using up more wood as well. One company told us that getting our chimney (masonry,on outside wall) piped would help? However since that's going to cost a lot of money we want to know that's going to help before we do it. I haven't been able to find anyone else having a similar problem so I don't know if anyone here can help but I wanted to try. We don't want to get rid of the fireplace, we really enjoy wood heat and it's what I grew up with but we have never had a problem like this before.

 

[jetsam]

I'm no expert, but it sounds to me like your unlined chimney is leaking into your living space. A new stove won't help, but a chimney liner will.

You probably only get less smoke with a hot fire because the stove is burning cleaner.

I would also invest in some (broken link removed) today if I were you, just in case you do have a leak.

 

[begreen]

Cold chimneys can reverse draft if there is negative pressure in the house. One would not notice this in summer because the windows are usually open and pressure equalizes.

If the insert is low in the house, particularly if it's in the basement, it could be in a negative pressure zone. This can be a major problem in a particularly tight house when fans in the kitchen or bath are exhausting. Dryers, and competing appliances can also contribute to the problem as can open windows or leaky attic stair doors on the upper floor.

An insulated liner can help, sometimes a lot, but it may not solve the problem entirely.

http://woodheat.org/all-about-chimneys.html

 

[Corey]

There are usually two sources of creosote smell.

1) The insert liner going through an old fireplace flue. In this case, the insert can heat up the old fireplace flue and bake some of the creosote back out of the masonry.

2) Backdraft through the insert liner itself.

Since you mention the smell only coming 24+ hours after the fire, it would seem like #2 would be the most probable. #1 is usually driven by heat which means it would generally occur when the fire / flue is the hottest or shortly after. I also notice your location in CA, this suggests you might see modestly temperate days, and 'chilly' nights, but not the 'solid' cold weather normally encountered. The temperate / chilly is much more likely to cause a flue reversal than when the weather is routinely cold.

You can try insulation, but 24-48 hours after the fire, how much heat is there to keep in? The insulation might help keep the flue a bit cleaner, though sounds like you're looking for elimination of the smell vs a small reduction.

There are a couple other steps which may help:

1) Close all air controls, vents, etc on the stove as tight as possible after the burn is complete. On an EPA stove it may be impossible to close them completely tight, but closing as much as possible will make it as hard as possible to get the backdraft going.

2) Break the backdraft. Air is flowing down your flue trying to fill negative pressure in your house. Why? Is something else...attic fan, bath fan, clothes dryer, etc trying to pull a lot of air out? Is the house slightly cooler than the warm outside air? If the outside air temp is acceptable, you might consider cracking a window to let in fresh air vs having it stream through the flue pipe.

3) Install a damper. This would be a "last resort" as it has extra cost and complexity. But a damper would provide a better seal of the flue than simply shutting your air controls.

 

[bholler]

so you do not have this insert hooked to a liner at all it is just slid into the opening? If that is true that is probably the issue and it is dangerous. If you do have a liner we can start to try to figure out other potential problems but we need to know that first.

 

[Woody Stover]

so you do not have this insert hooked to a liner?

That's how I'm reading it. So maybe he's got air being pulled down the masonry chimney due to negative pressure. That was a problem at my MIL's, even with a stainless liner to the top. So before I installed the Buck, I scrubbed out the smoke chamber of the masonry fireplace by hand, and installed a make-shift block-off plate made of Roxul insulation directly above the stove, and stuffed Roxul down from the top between the stainless liner and the clay liner. This pretty much stopped any air from coming down between the liner and the masonry, which I'm pretty sure would still be smelly if I hadn't blocked it off. I mean, I couldn't clean it all that well...but a certified sweep should be able to clean the masonry a lot better than I could. Then put in a stainless liner and block off as I described between the stainless and masonry. I don't think any reverse flow through just the inside of the stainless liner will give you any smell. But I always cap off the top of the liner in the off-season anyway (if you do this, leave a note inside the firebox so you don't forget it's blocked, and try to start it in the fall.)
I never tried to figure out where the negative draft was, just figured it was the warmer attic air going out the top of the house and pulling outside air down the chimney.

 

[Old puffer]

I stumbled across this tread and now I know why my creosote smell is strong after the fire has been out for over 24 hours. OP is not kidding about how STRONG the smell is.

Stove is in my basement, I have gas for dryer, hot water and main heat. That is what is pulling the air down the chimney because the warm air is going out the gas exhaust stack. I have major cold air coming down. Because my basement is way below ground, it rarely gets below 50 degrees. Now this all makes sense because we don't have the smell when it gets warm.

To lessen how strong of smell we have, we have bowls of white vinegar down there. It absorbs a lot of it.

The only way I can think of eliminating the problem is to put positive pressure via an electric flue fan on during winter days when I am not burning or disconnect the stove at the wall and seal it when it is cold.

Crap.

 

[Woody Stover]

we don't have the smell when it gets warm.

At my MIL's house, it stunk even in summer, that's why I think hot attic air was escaping and pulling air down the masonry.

The only way I can think of eliminating the problem is to put positive pressure via an electric flue fan on during winter days when I am not burning or disconnect the stove at the wall and seal it when it is cold. Crap.

Is your stove venting through a masonry chimney? If you have a direct-connect, and the block-off plate is sealed well where it meets the masonry, and then you figure out a way to seal between the hole in the block-off plate and the connector pipe, I think you can cut the stench substantially. Of course, the better solution is a "positive connection" with a stainless liner all the way to the top, then you can seal between the stainless and the masonry clay liner, top and bottom. Maybe others can advise how to neutralize the negative draft down there as well...
Here's a "direct-connect."

 

[Old puffer]

You can see my set up on my avatar. I goes right out to a masonry chimney. The stack is concrete block and is cold as the Dickens now. I am also wondering how much air goes to the attic, but then again the other appliances are making the updraft to there stack. It all makes sense now.

 

[begreen]

Do you have a key damper in the stove pipe to at least partially close off the flue?

 

[BobUrban]

My best guess is the info above is correct and you are getting a reverse draft. Probably really bad on heavy air days w high humidity. Two things that may help.
1. Burn candles inside the stove to keep it warm and flowing in the correct direction. I know this seems simple but it really works.
2. Another idea is to use an air inflated block in the flu just past the stove. Just put a note in the stove so you remember that it's there in the fall. Like a beach ball comes to mind.

 

[JAT]

Thank you for all the responses! We have really been struggling to get answers for this. We tried cracking windows and even sealed our house fan in the attic to try and reduce the smell but neither made any difference. The insert is just slid in, no pipe, no liner. We asked and were told that this model would work fine this way but apparently not. We had an older insert before that was also not piped but could never use it due to air pollution controls. Then CA offered a rebate and more burn days if we got the more efficient EPA model so we took the opportunity. This was not a problem with the old insert. Very rarely if the heater kicked on you could smell a little ash for a few minutes but that was all. This smell is strong and constant unless we build another fire, then it goes away for 24hrs. I understand the new stoves burn differently but it shouldn't be doing this. Thanks again to everyone for replying and helping us try to figure this out.

 

[Woody Stover]

I understand the new stoves burn differently but it shouldn't be doing this.

You have a "slammer" install. This may have worked with the old stove, which probably drew more air and flushed more heat up the flue. With the new insert, air is moving slower and less heat exits the stove, a good recipe for a build-up of deposits in the smoke chamber and clay liner of the chimney. Really hard to believe that a "certified installer" would do a slammer install....probably illegal (not in accordance with the mfrs. instructions) and might void your insurance in case of a fire. Get a different installer, one who is double-certified, and have him pull the insert, completely clean the entire interior (smoke chamber and clay liner,) put in a liner and block-off plate and do the rest of what was suggested above, then it should be pretty close.
bholler, who posted above, is actually a certified installer, as you can see in his sig...

 

[claydogg84]

Thank you for all the responses! We have really been struggling to get answers for this. We tried cracking windows and even sealed our house fan in the attic to try and reduce the smell but neither made any difference. The insert is just slid in, no pipe, no liner. We asked and were told that this model would work fine this way but apparently not. We had an older insert before that was also not piped but could never use it due to air pollution controls. Then CA offered a rebate and more burn days if we got the more efficient EPA model so we took the opportunity. This was not a problem with the old insert. Very rarely if the heater kicked on you could smell a little ash for a few minutes but that was all. This smell is strong and constant unless we build another fire, then it goes away for 24hrs. I understand the new stoves burn differently but it shouldn't be doing this. Thanks again to everyone for replying and helping us try to figure this out.

"Slammer" installs like you have are a thing of the past. Not only are they against code, but they are unsafe. This should be fixed.

 

[bholler]

Yup it is against code it is unsafe and it is causing your problem. If a "certified installer" put it in that way you need to report him to what ever organization certifed him so he gets that certification revoked

 

[begreen]

There is likely a major creosote collection happening above the stove as the smoke spreads out and hits the large smoke chamber and cold masonry. This is coating everything above the stove in gunk. The chimney is going to need a very good cleaning before installing a liner.

 

[Old puffer]

Ok, if he has a slammer install, what do I have? Look at my avatar. I just have a wicked down draft?

 

[bholler]

Ok, if he has a slammer install, what do I have? Look at my avatar. I just have a wicked down draft?

You simply seem to have a stove hooked into a masonry chimney. It can work fine but they can be prove to down drafts and hard starts. They also collect more creosote and that creosote is harder to clean. and lots of other potential problems

 

[begreen]

old puffer, tell us what you have from stove top to chimney cap. A dark and tiny avatar picture is not enough info.

 

[Old puffer]

Bholler is correct. Very old simple setup. To fire it up I get a lead casting kettle and put an ounce of two of whit gas in it. That gets the metal warmed to th point where I can start it,