Help! My wood stove is driving me nuts!

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Leumas

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Feb 25, 2013
4
Hello Forum,

My family and I moved into a new house a few years ago with a new Pacific Energy Super 27 wood stove. I'm not super experienced with wood stoves but know a little. I'm hoping someone here can help me out.

The problem I am having is smoke "back puffing" into the house whenever I try to add wood. I realize the installation is not ideal. The metal round pipe coming out of the stove goes into a rectangular shaped chimney (clay?) which is on the outside wall and enclosed by a larger brick chimney. The exterior chimney is larger than the pipe coming out of the stove so I believe this is negatively affecting the draw and causing the back puffing.

I try to only add wood when there is no flame in the stove. I open the door extremely slowly. I open windows and doors to try and help. Nothing seems to work. Even if there is only hot embers in the stove there is usually a waft of ash billowing out or whatever gases are present. It is also EXTREMELY difficult to light a fire in this wood stove.

The company who installed the stove came to look and suggested that I install a metal pipe from the stove to the roof top. One option was to install the pipe inside the existing clay chimney and the other was to remove the clay (extra $$). Apparently the pipe would JUST fit inside the rectangular clay chimney so I'm guessing the existing clay chimney is not much larger than the pipe coming out from the stove. The guy giving me this advice did not seem super confident about the solution so I thought I would ask opinions here.

The smell of smoke in the house is killing me! I work in an environment where the air quality isn't very good most days and to come home to a smoky house is awful. I also have two young kids. (3 and 1 years old). I hate exposing them to the smoke. Any help would be GREATLY appreciated!

Here are a couple pics of the installation.

P1090508.jpg
P1090510.jpg

Thanks

Leumas.
 
A cold exterior can cause this. Sounds like it may be dumping into something like a 7" x 11" liner. If so, draft may be hard to get started. Is the stove on the bottom floor or upper floor? A bottom floor install could be further complicated by negative pressure on that floor. Have you tried opening a nearby window a 1/2" to see if that helps?

Taking out the clay tiles so that an insulated stainless liner can be put in is common practice and may be the best solution here. The stove may also need an outside air kit (OAK) if opening a window helps.
 
I think the installers are very likely correct from your information.

What are the outside temps like in your area? I ask because warmer temps can have a negative effect on draft and I notced your grass is very green for January.
 
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Is the stove upstairs, or down? What height do you have from the top of the stove to the top of the chimney? What are the inside dimensions of the clay liner? In your stove manual, what is the minimum recommended chimney height? I don't know if the required stove clearances and hearth requirements would allow it, but if you could get the stove under the thimble, at least you would get rid of the 45* elbow. The best solution would be to put insulated stainless liner to the top. Looks like it's a straight shot, so it could be rigid liner, or flex. I wouldn't use a lightweight flex liner; To me, it's worth it to spend a little more on something better. Don't use two-ply smooth-wall either. Many problems have been reported. I've got HomeSaver HD RoundFlex on mine, but it ain't cheap.
Another factor inhibiting draft may be your fuel. It really needs to be split and stacked in the wind for two years at least, to guarantee good performance. You might get away with one year for quicker-drying woods like soft Maple, Black Cherry, etc.
 
Are there two clay liners side by side in the block chimney?
 
My buddy moved into a house and had smoke problems, turns out the pipe was pushed in too far into the flue. Something to at least check.
 
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It's not common. The Super 27 is an easy breathing stove. .
 
Which floor is that stove on? If the top floor the chimney is way to short.
 
If possible, shut the stove down, let it cool and remove the piping at the entrance to the brick and take some good pictures. Then a picture of the chimney outlet on top of the house, or at least a detailed description would sure help.

IMO, you have a very good grasp on what is going on. I wonder if the exit dimensions at the top of the chimney are causing the very poor convection current? I have no personal experience with doing this, but have seen it where people install a metal plate with a same size hole as the stove pipe and a short piece of pipe that has an actual rain and wind cap on it, on top of the chimney. It is not proper to do so as far as I know, but if it makes it function, then you can take it a step further and install the pipe liner inside the brick. Just an opinion, not any sort of advice.

Another question is, is there any clen out doors on the bottom of the brick chimney anywhere that are open or damaged?
 
Since I'm universally known for dumb questions, has the chimney been thoroughly cleaned recently?
 
I wouldnt use that stove again until you fix the draft situation, its not worth the damage to indoor air quality.
 
Thanks for the replies everyone. I will try to answer some of the questions.

Yes the wood stove is on the bottom floor. Opening the window nearby does seem to help with draw when trying to light the fire initially. However when adding wood to an existing fire the open window does not seem to help much at all. Even when the stove is nice and hot, the draw seems poor.

Winters here are pretty mild. 20-40 degrees F usually. Come to think of it when we have really cold spells I notice the fire is easier to start and back puffs less.

The clay liner dimensions I believe are 6x9" or maybe 7x11". The reason I say that is I know it is rectangular shaped and the guy who came to look said if they put in a 6" pipe it would "barely" fit. The clay liner goes right up to the exit point at the top of the chimney. There is no rain cover it is just open.

There are two clay liners in the brick chimney. One for the wood stove downstairs and the other for the fireplace upstairs. We do not use the upstairs fireplace at all. Another weird anomaly is sometimes I can smell smoke coming in from the upstairs fireplace. On calm days if we have a bathroom fan or the clothes dryer going I think it is creating negative pressure in the house and sucking smoke down the upstairs chimney from the other chimney. If I turn the appliances off the smoke stops.

Both chimneys have been cleaned and inspected recently and I was told they were very clean.

I watched the guy when he cleaned the chimney, he removed the pipe and elbow where it goes through the brick to the clay chimney. I'm not exactly sure how the pipe couples to the clay but it seems like there is a 90 degree turn there and then a straight shot up to the exit.

We are burning a mix of wood right now. Some isn't totally dry (one year in the shed) but there is some 2 year old wood as well. Mostly fir but some cedar and maple too. The problem doesn't seem to go away even with bone dry cedar.

There is what I think is the option for an outside air input on the back of the stove. I think the neighbor down the street has the same stove and uses this feature. He lives in a single story house and has no problem with his back puffing. Do you think using this outside air input would help?

I'm not sure of the exact distances from wood stove to the top of the chimney. We have 8' ceilings and it is a two storey house all above ground. So I'm guessing 25-27 feet.

There is a small clean out door on the bottom of the brick chimney. It is closed.

Thanks again for your help.

Leumas
 
Sounds like a liner in that chimney would be a very good step in the right direction...if not a complete cure
 
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Make sure the clean out door is completely 100% sealed. Break out the tiles, put in an insulated liner, and add chimney height as needed.

Inside the house, make sure the attic is air sealed and well insulated. Seal any ceiling lights, attic hatch, and outlets, etc. .. You are suffering from the stack effect ( I am too). Your house is competing with the chimney and trying to reverse it's flow.
 
If I was faced with your situation I would install a six inch stainless steel flex liner to see if this solves your problem before I went to the expense of having the clay tiles removed to make room for an insulated liner. Of course, if money is no issue, then removing the tiles and installing the insulated liner would be the better option. However, if you don't want to foot the large expense of removing the clay tiles you don't really risk much by trying out the un-insulated liner first. I say this because it is not that difficult to pull the liner back out and then insulate it and put it back in after you remove the clay tile flue. You would just add the insulation kit and slide it back in place. If on the other hand the un-insulated liner performs adequately you've saved a bundle of money.
 
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There are a few things to try. First make sure the damper upstairs is tightly closed. Maybe even put up something to block it (with a sign indicating that it is blocked). Air escaping or exhausting upstairs can cause negative pressure downstairs so making sure windows, that damper, and exhaust fans are closed or off may help. Another thing to try is sealing the cleanout door. Run bead of silicone around the rim and close it on that to make a gasket. Or just duct tape seal it for a test. Ultimately though it may take a combo of all these steps plus putting in the 6" liner and an OAK to solve the problem. Busting out the clay tiles should free up enough room to drop in a pre-insulated liner. That will help keep the flue gases hotter which will keep draft stronger.

To stop the fireplace from siphoning smoke also make sure that the new liner terminates with a cap that is about 12" higher than the adjacent flue.
 
If I was faced with your situation I would install a six inch stainless steel flex liner to see if this solves your problem before I went to the expense of having the clay tiles removed to make room for an insulated liner. Of course, if money is no issue, then removing the tiles and installing the insulated liner would be the better option. However, if you don't want to foot the large expense of removing the clay tiles you don't really risk much by trying out the un-insulated liner first. I say this because it is not that difficult to pull the liner back out and then insulate it and put it back in after you remove the clay tile flue. You would just add the insulation kit and slide it back in place. If on the other hand the un-insulated liner performs adequately you've saved a bundle of money.


With his chimney that liner will not go in or out easily. It will be a very tight fit if it is crooked at all and with the mortar joints. It could be damaged going in or out. Bust the tiles. It's worth it.
 
I have a similar setup going into a 7 x 11 clay liner. I had same issue trying to feed a larger flue with only the 6" pipe.
I figured out a fix and have been using it for several years now.

What I did was bought a 6" to 8" adapter to put right on top of the stove and use 8" pipe all the way to the
masonry flue that had an 8" Thimble.

I switched back to 6" just to double check that year and the issues returned.

Wood Stove Adapter pic.jpg
 
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In the lower level of our home we have a Woodstock Classic that is rear vented and has two 90 degree elbows on either end of about three feet of single wall pipe before entering a thimble into a 7" x 11" clay tile flue that runs straight up about 25 feet out the top of the chimney. In my case my chimney is in the center of my home, as opposed to outside. I have excellent draft and haven't needed to sweep the chimney in the past 15 years because it stays so clean. So, it is possible to burn a stove from the basement into an oversized clay flue and still have good results.
 
Is there a cap with a screen? Did you check it?
 
With his chimney that liner will not go in or out easily. It will be a very tight fit if it is crooked at all and with the mortar joints. It could be damaged going in or out. Bust the tiles. It's worth it.
Did you knock out the mortar snots ? , did you install the liner with a rope and pulling cone on the end . Sometimes the liner will need to be localized but you neeod to know the minimum square inches of the cross-sectional area of the stove exit collar.
 
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