Smoke problems with Heritage Woodstove

[Dottie]

With dry wood and an insulated liner there should be little creosote buildup over the season. The current setup is slowing down and cooling the flue gases too much.
For a certified installer go to this website and type in your zipcode: www.csia.org

Thank you for the links, I see that we have one new choice in my area, I'll try get an estimate as soon as I can (maybe not this season), but maybe.

 

[Dottie]

With dry wood and an insulated liner there should be little creosote buildup over the season. The current setup is slowing down and cooling the flue gases too much.
For a certified installer go to this website and type in your zipcode: www.csia.org

Hi,
For an update. Called the chimney people and the 1st appointment I could get was from a place about 50 miles away in January. I bought some fiberglass rods to see if I could clean from the bottom clean out door up, instead of from the top down. I could only get the rod in a little less than 4 feet and it seemed to get stuck or stopped by something. After a few tries, I got my little led headlights and put them in the clean out and took a picture with my camera. It's hard to tell, but to me it looks like a solid block of creosote.

If this is true how on earth did this happen? The chimney was cleaned with a brush and the stove has only been used 6 times or less this year. The first couple of times it burned fine then it started not drawing and smoking. In the photo, the walls of the chimney look clean until you get to what appears to be a solid block of creosote. I can't imagine how this could have occurred unless something got into the chimney and the creosote built up around the blockage after just a few fires. I have a new chimney cap over the top of the chimney, so I don't know how that could have happened. Any ideas?

Thanks.

 

[Smoked]

Take the brush off the rods and see if you can knock it out with the rods only. Then see what falls out. How well does the clean out seal? Cold air coming in there then mixing with the hot exhaust from the stove could be a problem. Gaps at the thimble pulling cold air or a crack in the liner doing the same thing? Chip it out and see what you have first though.

My first stove was a slammer I tried to direct connect. I did not know about block-off plates and never could get a good fit at the connection with the clay liner. I had a massive creosote problem right at that location. After the second chimney fire, I quit burning until I got a real stove and lined it all the way.

 

[Dottie]

Take the brush off the rods and see if you can knock it out with the rods only. Then see what falls out. How well does the clean out seal? Cold air coming in there then mixing with the hot exhaust from the stove could be a problem. Gaps at the thimble pulling cold air or a crack in the liner doing the same thing? Chip it out and see what you have first though.

My first stove was a slammer I tried to direct connect. I did not know about block-off plates and never could get a good fit at the connection with the clay liner. I had a massive creosote problem right at that location. After the second chimney fire, I quit burning until I got a real stove and lined it all the way.

Thanks for your well thought out advice. I found someone (not a professional) to climb up on the roof and I gave him a long piece of pvc pipe and he chipped out the blockage (actually two) and then cleaned everything out with the brush. He took a light and said that everything looked clean. I cleaned off the sides of the cap which had some creosote build-up. It has a solid top, but the sides had some creosote.

He looked at the wood and said although it wasn't green it wasn't really dried as much as it should be. I have a moisture meter somewhere that I just found last week, but can't remember where at the moment. If I find it I'll check and see.

Right now I'm starting my first fire. It's pulling air and burning, although I still have the side door open until it really gets going. I think that it would profit from a lining and a taller pipe for sure, but hopefully it can wait until after burning season.

The outdoor clean out is just a iron metal thing that sort of lifts up and opens. It doesn't have any seal, should I add one, if so, what kind? Also when you talk about the thimble, do you mean where the pipe inside connects to the wall? It just slips into a ceramic sturdy looking opening and seems to fit snugly, but again no seal materials of any kind, should it have some, and if so what kind and where does it go?

Anyway, right now I'm going to try and burn the stove hot at least once a day and keep an eye on the way it's burning and check the chimney (from the bottom), regularly. Hopefully this will be enough until fire burning season is over. I did wonder though, should you open the damper on the stove each time

 

[Smoked]

I have been burning a Heritage for 10 years now so am pretty comfortable with the operation, but I am not a chimney experts so please keep that in mind. Glad you found someone handy that could help you out too!

If the cleanout door is well below the entry point of the stove pipe see if it even gets warm when you have a hot fire going. If not at all, maybe simple weather striping could tighten it up. If it gets hot at all, maybe stove gasket tape and cement cold be used for a better seal. It has a latch, right? Where the pipe connects to the wall, if it seems pretty tight and no visible gaps, don't fret over it. If there are small gaps, stove pipe/furnace cement can be used there.

Every time I load anything, I open the primary air enough and long enough to get the top of the firebox full of flames. If I close it down too early and lose that blanket of flame, I open it back up to get that back. On warm reloading, it only takes a couple of minutes to get it rolling again. Cold starts, Primary is open for 5 or 10 min and then I start stepping it back. Normally by 15 min I am at a 1/4 and can get it close to all the way closed in another few minutes. Dry wood really is the key to having these things burn clean.

What was the stuff he knocked out like? Shiny and dense or something else?

 

[Smoked]

I went back and looked at your picture on page one. check behind that trim ring at the stone wall to see if you have gaps there if you have not already.

 

[begreen]

The problem could be damp wood and air getting into the flue. Make sure that the cleanout door is sealing tightly. If not temporarily seal it with a good metal tape or create a gasket by opening the door and putting a thick bead of silicone on the edge and then close the door on the silicone. Don't disturb, let it set up.

Try to get some dry wood to mix in with this wood. Use broken up pallets or some construction 2x4 scraps.

 

[Dottie]

I went back and looked at your picture on page one. check behind that trim ring at the stone wall to see if you have gaps there if you have not already.

Thank you for helping. It seems to fit snuggly into a ceramic pipe, appearing to be made for the size pipe, unless it's so fiddly that tiny dents would throw it off. No smoke comes from that area.

 

[Dottie]

I have been burning a Heritage for 10 years now so am pretty comfortable with the operation, but I am not a chimney experts so please keep that in mind. Glad you found someone handy that could help you out too!

If the cleanout door is well below the entry point of the stove pipe see if it even gets warm when you have a hot fire going. If not at all, maybe simple weather striping could tighten it up. If it gets hot at all, maybe stove gasket tape and cement cold be used for a better seal. It has a latch, right? Where the pipe connects to the wall, if it seems pretty tight and no visible gaps, don't fret over it. If there are small gaps, stove pipe/furnace cement can be used there.

Every time I load anything, I open the primary air enough and long enough to get the top of the firebox full of flames. If I close it down too early and lose that blanket of flame, I open it back up to get that back. On warm reloading, it only takes a couple of minutes to get it rolling again. Cold starts, Primary is open for 5 or 10 min and then I start stepping it back. Normally by 15 min I am at a 1/4 and can get it close to all the way closed in another few minutes. Dry wood really is the key to having these things burn clean.

What was the stuff he knocked out like? Shiny and dense or something else?

I'm sorry about not replying before, I just saw your post. The clean out space isn't hot, or even warm and I have a hot fire going now. I've been trying to burn really hot to help with the creosote.

I didn't have any regular metal tape at home, so I just sealed around it with silver colored duct tape. It's starting another really cold spell, so better sealing will have to wait for a warmer spell. I've had someone clean the chimney 3 times this year and every time I get about 1 1/2-2 gallons of creosote. It's the very light crinkly kind, not the hard glossy kind. It doesn't seem to want to stick to the walls, but does want to block up the chimney.

I changed wood suppliers this year and really like this one as he really gets the wood size and splitting just right, and most importantly helps me stack! He's a really nice guy who lives close by and unlike my previous wood deliverer .....well never mind about him! I've ask my new supplier to cut me some now if he can in order to give it more time to season, but I don't know if he has had the time.

I have some wood scraps from building a chicken house, but they are treated wood and I don't think you are supposed to burn those. I do have tons of fallen very dry juniper (Virginia cedar), but I thought that this kind of wood increased the creosote, do you know? If either of these are ok to burn I can try that right away.

Anyway, my fire starting routine sounds the same as yours, I along with everybody else I've read about gives up on the idea of the ash shaker thing under the bottom of the stove and just gets some of the ashes out of the stove door. I really lucked out in this house, I have a wood shed and it keeps the wood nice and dry. I just use my garden cart to fill with wood, push it down hill, and fill my large woodbox located right inside the door. The stove is located on right next to the woodbox on a raised platform type living room, it loads from the left side on the woodbox side and since it's raised a couple of feet above the floor where the woodbox sits I can see directly into the fire box of the stove and see exactly what I'm doing.

Anyway, I hope you will not take it amiss that I didn't see or answer your very helpful replies. I really the generosity of people who take the time to help out on these forums.

Thank you and take care.

 

[begreen]

Cedar should not cause excess creosote accumulation. Creosote is caused by the cooling down and condensing of wood gases in the flue system, not by wood species. We burn doug fir all year long and have burned cedar too with little creosote. This is because during the outgassing phase of the fire our flue temps are kept hot enough (above 250ºF) to not condense on the chimney walls. Normally during the primary burn the flue gas temps leaving the stove are around 500ºF. Our system is straight up through the house and has a double-wall connector which helps the flue gases stay above the condensation point inside the flue until the exit the chimney.

If you do burn the cedar make sure it is dry all the way through. Let the wood reach room temp, then resplit some and test for moisture on a freshly split face of the wood. This is important. Cedar and many coniferous woods can be high in oil content which allows them to burn well even if somewhat damp. The excess moisture cools down the flue gases. This is what causes creosote accumulation, not the cedar itself. If you do find that the cedar is fully dry then it can be burned, but note that it will burn hot and vigorously due to the higher oil content. Larger splits can help slow down this strong burn a bit.

 

[Dottie]

Ok, I'll try your suggestions. The metal tape will have to wait until my next trip to town, but if you think weather tape or silicone seal would be better, I can try the one you think is best.

The strange thing about the creosote problem is that this is my 5th year of burning with this wood stove in this house and it's the first year with any problems. This leads me to believe that it might be the wood. I do have a moisture meter around here somewhere that I have never used, the problem is remembering where I saw it last.

My stove vents from the top of the stove goes up maybe 18 inches then back maybe a foot to the thimble in the chimney wall. My stove never gets that hot. It's around 250-300 cruising by the thermometer on the soapstone. I have gotten it up to 450 or so, but it seemed scary hot. At 275-325 it will have a nice gassy burn after it gets it temps up and I throttle it back a little.

Talk about not too bright, I just tried putting the thermometer on the stovepipe about a foot from the stove and it was about 405 degrees. I don't know why I always took the temp on the soapstone.

Are you saying that the really hot burn before you throttle back a little should be 500 degrees on the pipe? Could you also tell me what the "out gassing phase" is?

Usually in the morning my stove has cooled down to 100-200 degrees (on the stone). I then get some ashes out, put on small then larger wood and leave the side door open until it catches and starts burning hotter. I've noticed if I close the door that the fire wants to die down, even with the damper all the way open. After it starts burning hotter, I'll burn a while with the damper open until I get that gassy burn and then I might damper it part the way down. I always damper all the way down when I go to bed. Does this sound right to you? If not, let me know what you would correct.

I really appreciate your help. I love my wood stove and although I probably won't be able to use it all my life, I plan on using it for as long as I can.

 

[Dottie]

Cedar should not cause excess creosote accumulation. Creosote is caused by the cooling down and condensing of wood gases in the flue system, not by wood species. We burn doug fir all year long and have burned cedar too with little creosote. This is because during the outgassing phase of the fire our flue temps are kept hot enough (above 250ºF) to not condense on the chimney walls. Normally during the primary burn the flue gas temps leaving the stove are around 500ºF. Our system is straight up through the house and has a double-wall connector which helps the flue gases stay above the condensation point inside the flue until the exit the chimney.

If you do burn the cedar make sure it is dry all the way through. Let the wood reach room temp, then resplit some and test for moisture on a freshly split face of the wood. This is important. Cedar and many coniferous woods can be high in oil content which allows them to burn well even if somewhat damp. The excess moisture cools down the flue gases. This is what causes creosote accumulation, not the cedar itself. If you do find that the cedar is fully dry then it can be burned, but note that it will burn hot and vigorously due to the higher oil content. Larger splits can help slow down this strong burn a bit.

I just looked behind the decorative trim (is it a timble?) and it looks like there is maybe an 1/8 inch of less in places and the trim thing was sitting about 2 inches from the ceramic opening that the stove pipe fits into. Since it's hot I can't put any sealant around it, but I did take a little hammer and knocked the round trim tightly against the ceramic opening. Hope that helps a little.

 

[begreen]

Furnace cement can be used around the pipe.

 

[Dottie]

Furnace cement can be used around the pipe.

Thanks for your help.

 

[Nate Dog]

To summarize these answers I'll first reemphasize Woody's advice: an insulated liner/smaller diameter flue. If you don't want that expense, then at least use some weatherstripping to make the cleanout hatch seal. Essentially the smoke exits the stove to find your large diameter masonry chimney, a big cold room, made even more drafty by an unsealed cleanout hatch. The smoke expands, cools, and condenses as creosote, right there, especially if it has any moisture in it. Take a look next time you start a fire. I imagine that the smoke isn't going *up* your chimney as much as it is *filling* your chimney and spilling out the top if it reaches it.

I got a heritage this winter, and it's a peculiar beast. I noticed that its flue temperatures are relatively cool, around 500, which doesn't help your problem in the slightest. To sum it up, my steel stove seems to blast the heat out of the wood, while the heritage milks the heat out of wood. In other words, the heritage runs cooler. If I open up the air all the way on the heritage, it actually cools the firebox.

I've learned that once I get combustion going, I can burn through a load faster at 1/4 open than I do at 3/4! This all translates to a hotter stove and flue as well. It makes sense, but is also somewhat counterintuitive-once you get your fire going, you will heat up your flue less if you leave the air open all the way than if you cut it back. A hot burn is going to be your best help against creosote formation. Don't be afraid, the manual says the heritage can get to 600F. I'd like mine to stay at 500 if I could get it there, but I'm usually cruising at around 400. I burn a lot of wet, unseasoned, and rotten wood (I use my stoves to help me clean up timber from my property) so I'm sure you could get to 450 easy with decent firewood. If that's too hot, maybe get a smaller stove, since stoves don't really work well at half throttle. To recap:

1. A smaller, insulated flue is most likely to solve your problem definitively.
2. Sealing the cleanout hatch would help with your existing setup.
3. Hotter fires of longer duration will generally help reduce creosote buildup (more smoke condenses in a cold chimney).
4. Drier wood will help prevent smoke stalling in your chimney.

 

[Dottie]

Thank you so much for your advice. I've been trying to burn hotter to prevent the creosote until I can do some of the steps that were mentioned. My stove never seems to get as hot as you have mentioned (405 degrees stovepipe temperature is the hottest I've seen).

I've been leaving the air open to achieve the hotter burn, putting the air about half-way after it seems to be roaring, maybe an hour or so after starting the fire. I close it down almost all the way to preserve the fire overnight, if I leave it getting more air that that it's turned to ashes in the morning. I guess from what you said, maybe this is not doing what needs to be done.

The stove still does heat the house pretty well despite it's problems with creosote this year, but I plan on doing something to resolve the buildup before starting to use it next year. I'm trying to get the wood cut as soon as possible this year in hopes that it's drier. I also have some fallen juniper that's been down for a few years that I can cut up to burn mixed with the other wood, maybe that will make a hotter fire. As soon as this season is over I'm going to do the sealing around the doors of the stove and the clean out door. If expenses allow, I'd like to get the chimney relined and maybe extend the pipe up higher to get a better draw and help stop the buildup.

 

[Smoked]

I have not been around for a while either Dottie and good luck! Get your wood now and get it dry for next season! If you can line the chimney, do it. it makes life so much better. The better draft will help you with temps too!