Fisher stove with 8" to a 10" ID terracotta to a rectangle 6x11 id flue

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HeatFisher

New Member
Sep 18, 2015
4
Virginia
Nothing is simple for me. Long story short:
Brought the house last year (2014), was made aware there was a fire in the flue in the 2012-13 season. they installed a HVAC. I'm a combination of broke, and a tightwad, I'll work harder if it means saving a dollar(or even .24cents.)

I ASSUMED (yes, I know that was my first mistake) that the 10 ID inlet through the concrete wall in my basement meant it was a 10' round flue. Drop a 8" liner in and hook up I'd be done.
Nothing is simple for me, because when I went up to the top verify the flue was cracked (and it is, about 2' long from the bottom up.) A few hairline cracks a foot or two down from the cap. I discovered I have a 6x11 rectangle ID flue. So, I've come up with a few viable options and would like some feedback please.

Option one,
pay the $1,034 for the oval liner and adapt to the 8" through the 10" ID. (Money forbids this option this winter...or the next 3 winters...maybe the next owners can do it.)

Option two,
apply mortar to seal up the cracks, I can reach the top of the crack using my "go-go gadget" arms. Use a Thimble ?(I think that is the term I have seen used to adapt to the terracotta "pipe".) Add a Damper, and maybe a flame arrestor. (Most likely)

Option Three,
Mortar up the cracks, get a oval flexible liner that's 6' tall (long, whichever) adapt to a thimble via a 8"pipe
the idea is to seal up the flue, and help keep some heat off the "weak link", meaning the crack that I seal up with mortar.

Now my questions,
Can you seal up terracotta with a mortar? Any recommendations? Also I am aware that the best technique would be to replace the tile, but again, money shuts down that option.

Concerning my worries about over firing,
From what I'm understanding, the bigger the piping is, the more heat it is going to pull up the stove pipe, and flue. Am I correct?
If I did the math correctly, the rectangle is approx 1.25 time the volume of the 8" piping.(First time since High School I had to use the pie formula, so I guess my teacher didn't lie to me.)
Should I worry about to much draft? or not to worry? Then toss in, if it is a factor to be worried about, wouldn't I be able to compensate with a damper? Also smoke doesn't travel through a rectangle has easily has a circle, so that extra volume will work in my favor...right?

now "Pipe" I am very aware, because of this forums awesomeness, that there are several different kinds and proper "pipes". Also that if you go through a wall you need a double insulated pipe. Now, I'm thinking it does not apply to me, because of the terracotta 10" id pipe that protrudes my concrete wall, and that would suffice any insulation requirements needed.....Right?


The outlet is in the back of the stove, from the center of the outlet on the stove to the flue is about 4'. The idea in my head is do a 90deg coming out, come up a few feet (install a damper in this section.) Do a 45 to the thimble (which will have another 45 degree connector.) Then into the thimble. Sound good?

I greatly appreciate any helping, tips, and have thoroughly enjoyed reading over this forum over the last week or more. If These answers are in some corner I happened to overlook, please direct me there, and I apoligize.

Thanks,
Single Income Family of 4 looking to save some money on heat this winter.
 
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Greetings. The flue size will work with the stove but the proposed options 2 or 3 are bandaid fixes. Mortar is not an appropriate fix. If the tiles are breaking down a stainless liner needs to be added. How tall is the chimney? When was it last swept? What is its condition up top?

When heating with fire safety has to be the first thought. Also important for safety is the condition of the stove and how one burns in it. If scrounging and a lot of poorly seasoned wood it burned, then followed by some dry pine or construction wood, there could be a serious chimney fire. Bandaid fixes don't stand up well to that kind of heat. If it can't be done right heat with the central heating system. The family is depending on your wisdom here.
 
The chimney from bottom to top is 15'. From what the neighbor says, the chimney was added on approx 10 years ago, aside from the cracked bottom tile, The inside looks amazing clean and neat. A few spots look a little black. as far has wood goes, I have approx 3 Cords of hickory, oak and a few other hardwood that's been split drying since last winter. I also have access to a few hardwood(or so I'm told) trees that were fell and cut up into manageable pieces mid summer. I would split those up, and dry out while I use the seasoned wood. My last resort wood is some oak and hickory timbers my work uses, those burn great, but fast.
I agree 100% on safety is Paramount, which is why I, after spending quite a bit of time researching, which kept leading me to this site, I decided to get some more options.

A liner is my first option, and when I realized the shape of the flue it sent me into a whirl wind of ideas. Has mentioned above the only liner I've been able to locate is more than $1000. I can deal with paying $5-600 for a liner kit. Which would still be a savings over last years heat bill.

Is there a different liner that would work? It seems my style flue isn't rare. I'm tempted to ask if I just buy a 8" liner will it crush enough to fit? But I think it may cause some leaks.
 
Good to hear that the chimney is not too tall and in overall decent condition. I am not a mason and can't see what you are seeing in the chimney. It's hard to say whether refractory cement would buy you a year or two or not. I think not and suspect it would either fall off on its own or with the first chimney brushing. Sounds like 8" ovalized liner may be the way to go, but wait for one of the pro sweeps to comment on your options.

Hickory and oak are excellent firewood but they are also slow drying wood. They need a couple years to fully season after being split. Partially seasoned wood will burn, but it will also sote up the chimney. The way to tell if it is ready to burn is to resplit some pieces and test the freshly split faces of wood with a moisture meter. In lieu of a meter you can put the freshly split face up against your cheek. If it feels cool and damp, it is. Also if you bang together a couple splits they will thud if damp and will sound a musical note if they are fully seasoned. If you have ash wood in the mix, it will dry the fastest.
 
For lack of better terminology, it "clatters" LoL. Dry to cheek, No thudding. I doubt it's fully season cured wood, but it's dried out. Thanks for the advice!
 
Sealing a crack in a flue tile will not work. The mortar will not stay and it may even cause more cracking. One option would be to have it inspected by a professional. If they determine that the crack was from a chimney fire your homeowners insurance will probably pay to line the chimney. If you have it lined i would strongly recommend having the tiles broken out and install an oval or rectangle liner with insulation.
 
It happend before I brought the house, home insurance won't touch it. I think I found a decently priced liner. going to call Monday to make sure the od will fit. If I just install a liner, leave the tiles in place, would I have to insulate the liner?
 
Yes, you probably should, but even just lining it is going to be a step safer than running with the cracked tiles.
 
Yes you should but like begreen said an uninsulated liner is better than none.
 
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