Six inch stove pipe thru 8 inch thimble?

[weistk]

I am installing a Regency woodstove in my basement, there is an existing hearth and hearth floor there and an eight inch thimble going into (18 inches deep) a masonry chimney, the stove has a six inch outlet and I'm installing 6 inch stainless steel flex pipe from top of chimney approx. 22 feet. My dilema is the thimble at 8 inch doesn't work with my pipe, does anyone have a suggestion?? Can I somehow run a 6 inch pipe through the 8 inch thimble and seal it in there with something???

Thanks,
Weistk

 

[Todd]

I had the same problem, this is what I did. I put an 8 to 6 reducer on my 8" thimble, then I connected a 6" long double male pipe to the end of the liner. Then brought the liner through the thimble into the reducer, screwed and cemented the gaps in the reducer, and connected the stove pipe to the reducer. Hope this makes sence.

 

[struggle]

If you have to make a turn such as a 45 deg turn you will not make it with a 6" flex liner. I relined a existing 8x8 clay tile chimney and barely made the 45 deg turn with a 5.5" liner. What is your internal measurement of your clay liner?

There was no way a 6" would go down mine. I had to be on the roof pushing the liner down as a person in the house pulled on the liner.

I would for sure measure to double ceck the internal measurment of the existing clay liner and to what degree does it turn toward the wall thimble.

Mine made to 45 degree turns toward the thimble.

Flex liners while flexable do not make turns I would say beyond 45 deg. If one did I would guess it would seperate at the seams.

My chimeny is about the same lenght as yours. If you decide you cannot make the turn then better to go with the 5.5 liner as I doubt you can return a liner that has been attemped to be installed.

 

[BrotherBart]

Forum member Todd and I both have made the 90 degree turn into a thimble with a 5.5 liner. It ain't fun but can be done. Your challenge is what you use to connect the interior six inch pipe to the end of the 5.5 flex. The world is noticeably devoid of 5.5 hardware. My tiles are 7 X 11 inside dimension and the thimble is 7 inch.

 

[wally]

Can I somehow run a 6 inch pipe through the 8 inch thimble and seal it in there with something???

there are a few different brands of "reducers" and "expanders" that will solve your problem. i have the opposite issue, as the outlet is 8" and the thimble is 6", so i use an 8" to 6" reducer. you'd be looking for a 6" to 8" expander. these are single-piece units, just like a section of stove pipe.

 

[Gooserider]

Depending on your setup, another option might be a "detachable snout" Tee fitting... These are designed to be a smooth barrel body with a hole in the side that can slide straight down the flue with the liner, you then reach in through the thimble with the snout peice (after adding whatever additional SS rigid pipes you need to extend the snout out to the face of the chimney), and attach it to the barrel, usually with a couple of screws. The biggest problem is probably getting everything lined up and then reaching in the pipe and getting the screws in place. Obviously this requires that you have enough room below the thimble to fit the body extension, and that the thimble and flue are fairly close to a right angle.

You would also then need to figure out a way to close the gap between the OD of the 6" "Tee" and the 8" thimble, but that shouldn't be a terribly difficult problem.

Gooserider

 

[struggle]

Like others said getting the right fitting to go from 5.5 to 6" is a bit of a fuss. My neighbor (owns a machine shop) fabricated me a heavy guage peice of stainless steel pipe to fit snug over the 5.5 liner and be able to slip 6" 90 over that to go down to the stove.

I had said neighbor then build me a block off plate of sorts to slip over the peice he made so it would cover the area that would have been filled by the old 8" pipe that came out of the thimble before with a tab on top of the plate to attach a heatshield.

 

[weistk]

Just thought I'd post an update on what I ended up doing to install this stove, I was unable to use the 6" stainless flex liner due to the fact the clay tile was 8" x 6 1/2" but not laid perfectly on top of one another when I tried to install the liner it stopped dead at where the first tile met the second. Also the thimble which was installed previously, is partially off set making it impossible to use a tee. I ended up fabricating an adapter to mount at the inside end of the thimble off set and slightly up of center to give a slight rise. In it I installed a stainless seamless pipe 6" in diameter and then that vents into the clay flu which is in great shape. I was keen to use the flex stainless in the chimney for ease of cleaning and safety. I am still thinking of installing the 5.5" flex as was suggested above, however I am reluctant to do so as it is smaller than the original and it's approx. a 22' flu which I have been warned not to reduce the dia. size due to the length.

Anyhow the stove is working great, but is still a work in progress.
Thanks to all for the suggestions,

Weistk

 

[struggle]

The 5.5 liner will work and draft really good or at least it does with my set up. It actually drafts so well that I had to install an inline dampner above the stove or the stove would overfire to easy.

I was lucky enough that the place I bought the liner from told me that there was no way the 6" would work and they were right. To bad you went through this. I am unsure about how a direct connet as it seem you have will work or as to how safe it is. Other might be of more help on that.

 

[Gooserider]

Just thought I'd post an update on what I ended up doing to install this stove, I was unable to use the 6" stainless flex liner due to the fact the clay tile was 8" x 6 1/2" but not laid perfectly on top of one another when I tried to install the liner it stopped dead at where the first tile met the second. Also the thimble which was installed previously, is partially off set making it impossible to use a tee. I ended up fabricating an adapter to mount at the inside end of the thimble off set and slightly up of center to give a slight rise. In it I installed a stainless seamless pipe 6" in diameter and then that vents into the clay flu which is in great shape. I was keen to use the flex stainless in the chimney for ease of cleaning and safety. I am still thinking of installing the 5.5" flex as was suggested above, however I am reluctant to do so as it is smaller than the original and it's approx. a 22' flu which I have been warned not to reduce the dia. size due to the length.

Anyhow the stove is working great, but is still a work in progress.
Thanks to all for the suggestions,

Weistk

As long as your clay flue tiles are in good shape, I think you'll be reasonably safe with that setup, and it should work OK - 22' is a nice chimney height, and 8" x 6.5" internal dimensions is only 52" of cross section, which is under the 2x outlet size limit for an external chimney (56.5") in the NFPA rules, (and clearly under the 3x limit for an internal chimney) Cleaning shouldn't be that bad, other than that you'll have to do the chimney from the top, or go in through the ash cleanout (if you have one) and have two brushes, one for the flue and one for the connector pipes.

The 5.5" flex would probably work, but it would also probably be OK if you were to slightly ovalize the 6" that you already have, assuming you can figure out how to hook onto it at the bottom.

Gooserider