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Need some help with a defecting DIY stove installation

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Cord, Jun 5, 2006.

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  1. Cord

    Cord Member

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    I've been battling my home for a couple of years and keep on loosing. The home was built in 1941 and has a clay lined chimney. There was a original steel insert fireplace when we bought the home. The insert was not very efficent so we removed it and installed a Franklin stove. I quickly learned that these Franklin's were pretty horrible stoves and quickly replaced it with a Jotul I bought used locally. After a while, the Jotul didn't seem to be working very well and I found that it was a Chinese knock off and was missing several burn plates. We removed the Jotul and replaced it with a Vermont Castings Encore. This is the current stove. The first year we burned the stove, I noticed that it didn't seem to be heating as efficiently as it should. The stove was barely able to maintain 68 degrees in the living room. Our entire home is only 900 some square feet with much of that space in the living room so we should be having to open the windows and dump heat! The next spring I noticed some glazed creosote in the flue and very little dust was created when I brushed the cimney out. There was also a space where the creosote had liquidfied and dripped from the flue creating a puddle behind the stove. Hoping the cat converter was bad, I replaced it with a new one and burned for another season. The results were the same with a continued build up of glazed creosote. At this time, I'm not comfortable using the stove and would like to solve the problems before the season starts. Lets run down my installation:

    The stove sits on the hearth in front of the old fireplace opening. The flue pipe comes off the back of the stove, travels horizontally for 18", converts to a 8" round pipe, turns up, and then enters the flue. The original damper and smoke box have been removed. The clay flue pipe measures 7"x10" inside dimensions and has a slight jog, but sky can be seen from below. There are some masonry defects dating back to the original chimney construction. One of the flue pipes shifted during setting and does not align with the tile below. You can actually see the structural bricks through the gap. This is not a new defect, but one that has existed for 60 years. We burn well seasoned wood, two years under cover, mixed hardwoods - mostly elm. If I disconnect the flue pipe in winter, I get a pretty good draft up the chimney. Now that it's summer, we are getting some reverse drafting. Occassionally, I get a stinky creosote smell in the house. The house leaks well enough that venting hasn't been an issue. I've tried to crack a window when the stove was burning and saw no change in it's performance.

    I believe my problem is one of two things: The short horizontal run off the stove and/or the existing flue. There isn't a whole lot I can do with the horizontal run, so can we talk about my flue? If I calculate the area of the existing pipe, I see that it's slightly larger than the 8" round pipe which is recommended for the stove. My understanding is that the 8" pipe is recommended to prevent back puffing. I talked to my local stove supplier and we both agree that the cimney could be relined. The problem is trying to fit the correct sized liner in. A 8" liner won't fit. He warned me that the easy fix would be a 6" liner, but that the liner would be undersized. He thought it would be Ok, so long as I didn't burn with the doors open. I'd like to get some other opinions as to the best way to fix my problematic wood stove.

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  2. Eric Johnson

    Eric Johnson Mod Emeritus

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    If you can see bricks where there should be liner, you need to re-line the chimney. That will probably solve your problem, which sounds to me like a draft issue, probably aggravated by an improper connection to the flue. Your existing set-up doesn't sound safe to me.

    As to the best way to reline, experts abound on this board.
  3. Cord

    Cord Member

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    I agree with you in that I'm facing a reline. I'm pretty certain the source of my problems is the flue. The biggest question is, do I have to bust out the existing liner and fit a 8" flue (which proably won't even fit with the insulation) or can I get by with a 6" pipe? As a experiement I tried to fit a 7" rigid pipe down and it wouldn't go. The pipe was catching on the flue joints and wouldn't drop in the last couple of feet.
  4. Eric Johnson

    Eric Johnson Mod Emeritus

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    You can get ovalized liners and you might find an appropriate one that fits.

    I would get a different stove (most modern stoves use 6-inch exhaust outlets) before I did anything drastic to the existing chimney. A lot cheaper and probably more efficient when you get right down to it.
  5. Cord

    Cord Member

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    Well, a 8" round gives me 50 sq in area. A 6" round = 28 sq in. A 6x8 oval = 40 sq in. The oval might be a good compromise between size and the need to break out the liner.

    The stove is a modern one that is still in compliance for a air tight unit. As I understand it, the flue is oversized to reduce back puffing from either the top load or when the stove is burned with the front doors open.
  6. saichele

    saichele Minister of Fire

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    The official line is that you're not allowed to reduce the cross sectional area below the manufacturers specification. In leiu of that, the collar dimension. So if you reduce the cross section, you;re not likely to pass inspection for your permit.

    That said, it's quite a coincidence that just about every stove sold in NA requires either a 6" or 8" pipe. Obviously there's some rounding and upsizing involved. Unfortunately in your case, it sounds like you have a drafting problem anyway, so cutting that back isn;t likely to make things better.

    I think you have two choices. 1) get someone in to break out the clay tile, or 2) find a liner that fits inside. There are all kind of shapes out there not, including rectangles, so you could probably get a 6x9 to make you legal.

    The catch, of course, is that the stuff is crazy expensive. So you need to surf the web a bit, see what kind of prices you can come up with for the length you need, and see what it would cost to get the tile knocke dout and drop regulr round pipe in.

    I think it's safe to say that if you can see brickwork in the gaps between your tile, particularly given a creosote problem, you chimnye is dubious if not downright unsafe.

    Steve
  7. Eric Johnson

    Eric Johnson Mod Emeritus

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    Insulation is another consideration. I don't know if you can wedge a single-wall ss liner right up against a clay liner or raw brick. I'm guessing you can, but it's one more thing to check.
  8. elkimmeg

    elkimmeg Guest

    You describe the classic example of what happens, when cold air mixes with the stove draft, glazing. I would never have issued a permit without a chimney condition report. Once it was noted it to be defective ( liners exposing bricks) I would never issue the permit till it was rectified. I suspect cold air entering threw the defective flue

    You also made no mention of a block off plate? What is the vertical length? My guess your chimney is located on an external wall with 3 sides exposed to the outside?. The stove is probably a hell of a lot better condition than your chimney.

    What to do? Its unanimous it should be fully lined. Fortunately the Encore was tested and specked out to be able to operate with an optional 6" flue collar. VC also makes an 8" oval to 6" round flue piece that can be used. The disclaimer is, the open door spark screen option cannot be used with the 6" flue. If you convert to a 6" flue, you then can run a 6" liner the rest of the way. Your situation is a draft issue not stove. However after a year of inefficient burning due to poor drafting, chances are ,even your new cat is gunked up. It will require cleaning. Don't stop there, vac out the entire cat chamber. No sense leaving fly ash there to clog it up again. There is a thematically controlled secondary air prove, it too may need cleaning to sense temps right.

    In your case, I highly recommend that you insulate your liner. The key you have to deal with is getting the liner by the off set. Also install and seal a proper damper block off plate.
  9. Cord

    Cord Member

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    I believe the existing flue is around 12-15'. It's actually a interior chimney, but because of the roof slopes, half of it is exposed above the roof line.

    That's exactly what a local distributor was saying (he didn't deal with the VC's so he really knows his cross brands). He thought you could use a 6" pipe, but no longer have the feature of the open door burning. My guess is that the cost increase of the larger liner will make the 6" an obvious choice.

    When you say "damper block off plate", are you reffering to a second damper on the chimney? If so, then there currently is not a damper on the chimney, just one in the stove.
  10. Eric Johnson

    Eric Johnson Mod Emeritus

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    He's talking about the place where the stove pipe connects to the liner. You need to block off the space between the new liner and the old fireplace damper opening. There's no damper, in other words, but there is still a place where it used to be that needs to be sealed off around the new liner.

    That's very good news about the Encore being able to vent into a 6" liner. That's going to save you some real money, given that round, 6" stainless is the most widely used, and therefore least expensive, lining alternative.

    You have several insulation options. I'll be curious to see what people suggest for your situation.
  11. elkimmeg

    elkimmeg Guest

    Insulation for the liner can be achieve two ways. One if space allows, wrap the liner with the protective mesh.

    The other way is to use poured in insulation like Thermax. but for it to work you will need to contain it. That's where the damper block off plate comes into play. The other issue is centering in in the chase so the insulation evenly dritributes around it. Some use spacers brackets installed on the liner to accomplish this. Your situation with the offset, may require working spacers from the bottom and top to get by the offset. Do the best you can in that transition area. What I would do it cut slits about a foot long in the liner and compress it into a cone like shape. Duct tape it and have a rope run threw it to help guide it. After fished threw the flue, I would cut the bottom cone area off. You might consider a tee 90 conversion behind the stove. It would make cleanind a breeze.
    With the liner is in place, cut a piece of sheet metal to form your block off seal. Cut out a 6" round hole where the liner will pass slide the block of plate around the open end of the liner pipe and tapcorn it into the bricks. With a tube of hight temp fire block or refactory cement and caulk and seal the damper plate and the concrete connection. You may find it best to lay a healthy bead of caulk there first. When you have made the connection to the stove. Caulk (same caulk as used previously) the space between the block off plate and the liner. At this time you can now pour in the insulation. Let the liner extend up a bit, if you have another flue in this chimney. Cut the liner install a top block off plate, then the termination cap. You can let the liner extend up a bit but no more than 4 to 8" or not al all. If there is another appliance connected, it is good to have a separation distance of exit points. I sure others will add to my basic instalation description
  12. Eric Johnson

    Eric Johnson Mod Emeritus

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    That's a very good description of the process, I think.

    Containing poured insulation in a brick chimney can be a challenge. The material I've had is basically vermiculite mixed with cement, and once it finds a hole, it tends to pour out. I've never used the fiberglass wrap, but it's supposed to be superior (though perhaps more expensive), and it needs to fit. I believe that a rigid, sectional liner is the least expensive alternative, and probably superior to a flex liner, assuming you can make it fit. You can wrap either one with insulation.
  13. Cord

    Cord Member

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    I'm debating if I really want to try this repair myself. I know a 6" rigid pipe will drop down super easy and then the pour type insulation would finish the job. I prefer the round pipe over an oval because I can get a brush to actually fit it. Right now I have a stainless plate tap-coned to the bottom of the flue to receive the 8" pipe. I can remake the block off plate to fit the 6" pipe easily enough. I'll also make a new top plate for my chimney. I want to block off the abandoned adjacent flue and make the plate so it'll flash the top of my chimney. If I'm lucky I can reuse my chimney cap. I saw some the other day that had a band of stainless surrounding the bird screen. What is the band for? I like the idea of a bottom T, it would help keep me off the roof. Gotta save those shingles. The thing I'm not sure about is the transition from a 8" to 6". Don't forget, my stove has a 8" oval outlet.

    I have an expert coming out Friday to give me an estimate for a reline.
  14. Eric Johnson

    Eric Johnson Mod Emeritus

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    You can buy a reducer section that transitions you from the 8" oval to the 6" round.

    I don't know what the band is for, but I always remove the screens from my caps. They're creososte catchers.

    Cleaning an ss chimney from the bottom is about a 10-minute operation. Do it more often and worry about it less.
  15. elkimmeg

    elkimmeg Guest

    VC makes a 8" oval to 6" round adapter pipe I believe about a foot long. Lunch break. when I get time I will try to post a picture
    Another way is to use an 8 to 6" adapter attached to your original 8" oval to round attached to the stove. Third way is to buy the 6" flue collar from Vermont castings..
    A link for the oval to round pipe fitting

    http://cgi.ebay.com/Vermont-Casting...ryZ20598QQssPageNameZWD1VQQrdZ1QQcmdZViewItem
  16. Todd

    Todd Minister of Fire

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    If I can reline my chimney you can, unless your afraid of heights? Lots of people line their chimneys without full insulation and have a great draft, like me. You may not need it unless your chimney is an outside type and you live in a very cold climate. Since you have a inside chimney, maybe try it without for awhile or just wrap the top few feet, this will leave an air space inside that will keep the chimney warmer. Just having the 6" liner alone will increase you draft over your 7x10 flue. This may save you a few bucks. Also make sure you clean your chimney good before relining.
  17. Shane

    Shane Minister of Fire

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    Be warned that if you choose to go with the uninsulated method, while it may work, your liner could technically be installed improperly. Draft benefits aside one major reason for insulating liner is to get a zero clearance rating for the liner. Technically your chase is supposed ot have a 2" clearance to combustibles when enclosed in the building envelope. 98% of chimney chases are built with no clearance to combustibles, thus the need for a zc rating on the new SS liner.
  18. Cord

    Cord Member

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    Unless it's ungodly expensive, I'd proably go with the pourable insulation. Seems to be much easier to install than the wraps. Maybe you guys can clairify why a lined chimney would need to be insulated when it's relined? I mean if we insulate it, then I wouldn't even need the clay liner! Actually, the lining project doesn't scare me. It's custom making the top and bottom plates. This is only the 4th time I've messed with this flue. Should have just ripped the dang thing out, but I just couldn't picture the house with out a chimney.
  19. elkimmeg

    elkimmeg Guest

    All you need is a pair of tin snips. Get a piece of cardboard and use it for a template of your existing former damper area. Sheet metal pieces can be bought at Home Cheapo as well as refractory caulk One can also buy as damper plate block off kit and the roof top kit. Cutting a hole it is not a big deal, once you hae punched a starter hole or drilled one. Then nip out the center and work to the outside diameter of the pipe. One other concern you may improve. Extending the liner up a bit or attaching a piece of class A chimney to iT. If you verticle lenght is 12 ' and with an off set, that is not enough height to develope a decent draft .

    I think you have run the gambit of failed and compromise attempts. If serious about wood burning, then time to make good decisions. Your pro installer is stopping by go threw this post and ask all the questions and concerns we pointed out here.

    BTW where do you live PM me if you do not want to post that info
  20. Cord

    Cord Member

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    I live in SE Wisconsin.
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