Inside diameter on 8X12 clay flue

[Skitheeast]

Hi Everyone,
I recently attempted to drop a 6" ss liner down my masonry chimney with no luck. There was an offset that we could not get by. I contacted a friend who does this for a living to give me a hand, and he was able to get his hands on a 5.5" and come out this past weekend to install with me. The 5.5 would not fit / get past the offset. We did everything, pushed pulled with rope / nose cone etc... would not go. After we were done, he measured the inside diameter of the 8X12 clay flue and said it actually measured 6X10 inside?
My question is this; What does the 6X10 equate to in a round diameter? and, could I use this flue with an Englander NC30? The exterior chimney was built in 2009 and is approximately 30' tall from the masonry thimble in the basement to the top of chimney.
Thanks in advance for your help-
PS, anyone want to buy a couple ss liners?

 

[Oldman47]

The cross sectional area of a 6x10 is a little more than an 8 inch round pipe would be. That is not the whole story though. Gasses flowing through any pipe will include both laminar and turbulent flow regimes and the material smoothness, size/shape and flow rates will all affect those. I have no idea of the safety factors involved but it seems likely that the 6x10 will provide far more area than you need or want for a stove designed to use 6 inch pipe.

 

[Fsappo]

6x10 gives you the cross section needed. If you were concerned and had more liner than you needed , cut off a 2' section of the 6", not the 5.5, oval the 6" to 5x7 and see if that goes down. How far from the top or bottom of the chimney is that curve?

 

[Skitheeast]

6x10 gives you the cross section needed. If you were concerned and had more liner than you needed , cut off a 2' section of the 6", not the 5.5, oval the 6" to 5x7 and see if that goes down. How far from the top or bottom of the chimney is that curve?

What do you mean it gives me the cross section I need? The offset is probably 5' or 6' or so up from the thimble.

 

[Skitheeast]

6x10 gives you the cross section needed. If you were concerned and had more liner than you needed , cut off a 2' section of the 6", not the 5.5, oval the 6" to 5x7 and see if that goes down. How far from the top or bottom of the chimney is that curve?

We did ovalize the end to try to get it by the offset with no luck.

 

[mellow]

Run a camera down the chimney and get a visual on what you are up against.

 

[Nick Mystic]

I have a Woodstock Classic stove in the lower level of our house that vents into a clay tile liner about the same dimensions of what you have. It is about 25' tall and drafts fine. I never have any negative pressure issues and the liner stays exceptionally clean. In my case I have a 90 out the back of the stove and a second 90 elbow about three feet up that goes into an 8" clay thimble that is mortared into the clay tile liner inside the chimney. Your situation would require some custom fabrication to make the connection from your stove to your clay tile liner. You would need to somehow make an airtight seal between your 6" pipe coming off your stove and the rectangular clay tile liner. Since that would be up above your smoke shelf I don't know how you could do it. You might have to hire a mason to cut a hole through your chimney above the smoke shelf and insert a clay tile thimble similar to what I have with my set up. Good luck.

 

[bholler]

It might work ok it might not But you could hook it up and see. But i agree with mellow i would have it scanned to see whats going on in there

 

[Skitheeast]

I have a Woodstock Classic stove in the lower level of our house that vents into a clay tile liner about the same dimensions of what you have. It is about 25' tall and drafts fine. I never have any negative pressure issues and the liner stays exceptionally clean. In my case I have a 90 out the back of the stove and a second 90 elbow about three feet up that goes into an 8" clay thimble that is mortared into the clay tile liner inside the chimney. Your situation would require some custom fabrication to make the connection from your stove to your clay tile liner. You would need to somehow make an airtight seal between your 6" pipe coming off your stove and the rectangular clay tile liner. Since that would be up above your smoke shelf I don't know how you could do it. You might have to hire a mason to cut a hole through your chimney above the smoke shelf and insert a clay tile thimble similar to what I have with my set up. Good luck.

Hi Nick,
My set up is a 45 off stove into 48" stove pipe run to another 45 connected to the masonry adapter to the masonry thimble. The masonry adapter is a 6" and the masonry thimble is a 7" round. I stuffed rockwool around the masonry adapter to achieve a decent fit. The house is tight, built in 09'. The fire in the stove won't stay going when I close the door even with the air draft rod wide open. I'm wondering if I need an outside air intake kit.....Any and all help appreciated.
If it helps any, I originally used to have a wood burning furnace hooked up to this, and we could not get it to operate correctly. It was a large unit from a respectable co. -It would constantly fire up, start and stop within a few minutes, never providing enough heat to do much of anything....

 

[Nick Mystic]

Have you tried using a piece of incense or a blown out match in front of your stove opening to see if you are pulling a decent draft? Or in front of the thimble if the stove isn't connected? From your description of multiple burning devices not being able to maintain a fire and with your inability to snake even a 5.5" liner through your flue it sounds like something is blocking your path. Did you have this chimney swept before you made your attempt to install a liner? If not, that would be the place to start since you have to have a clean flue before you can install a liner, even if the liner was able to slide right through. When you get the sweep done you might discover what your problem is. Good Luck.

 

[Fsappo]

We did ovalize the end to try to get it by the offset with no luck.

Hmm. I have, under extreme circumstances where the customer insists I proceed, Located the place where the liner was catching, by marking off the distance the liner went down the chimney. Then, carefully open the chimney from outside. I think 4 times in 20+ years. Every time I recall it solving the problem, simply by a push or pull thru the created hole and in once instance found a choke point in an offset where an 8x12 tiled chimney had a non tiled section in the offset that narrowed down to 4x4 or so, before opening back up.

In that case, we installed a VC Radiance B vent instead of a Resolute Accliam (that should age the story!)