Pipe for the Clayton 7.1

Hi all,
Going to get new pipe for the Clayton 7.1 Burning only anthracite in it, and I will have about a 4' run to the chimney thimble. Thimble is 8" dia and stove outlet is 6". Two ways to go with this, that being upsize to 8" directly at the stove or run 6" to the thimble and upsize then. Just thinking if there might be some advantage by doing it one way or the other?? There will be a 19" rise from the stove outlet to the center of the thimble. This will provide a decent up-angle for the pipe?

A third way would be to stay with 6 inch into the thimble and pack the 1" space around the pipe with rope gasket, fire stop caulking, fiberglass insulation or a combination of the 3.

edit: there are many products I left out to fill the space with.

It is best to stay 6" until you get to the vertical chimney, going larger will reduce gas speed and fill the stovepipe with ash sooner. IIRC, a 6" thimble should slide right into an 8". Just make sure nothing (stovepipe or thimble) actually gets beyond the chimney's interior wall.

coaledsweat wrote:It is best to stay 6" until you get to the vertical chimney, going larger will reduce gas speed and fill the stovepipe with ash sooner. IIRC, a 6" thimble should slide right into an 8". Just make sure nothing (stovepipe or thimble) actually gets beyond the chimney's interior wall.

You just answered a fleeting thought I had about a 6" thimble into a 8". Guess I'll include a 6" thimble along with the 6" pipe & baro damper. If I have space to close between the thimbles I have some thin fiberglass sheeting that ought to work well.
As an afterthought, I told my wife as soon as I get my coal stoves installed the weather would finally break and it's looking that way. But, just 3 nights ago it went down to -15 deg so we may not be "out of the woods" yet.
Thanks for the replies!

Some confusion on baro dampers. I see online prices (for 6") ranging from $100 down to $40. I see gauge of pipe has a lot to do with it. 24 gauge seems to be the higher price. Are these heavier models really preferable? Will I be changing out the cheaper ones two or three times when a $100 one will outlast several cheaper baros?

Field Controls for the damper. A very good commercial product. Most members run the R/C model, about $40. The M is what Field Controls recommends for coal, about $70. It has the ability to swing both ways relieving pressure in the event of a puffback.

Another question on the Clayton. When I lift the grate shaker handle the grates tilt to the rear end of the firebox. When I lower the handle the grates tilt toward the front end of the firebox. I need to lift the shaker handle a couple inches to get the grates back to center and not tilted. Are the grates only supposed to tilt to the rear of the firebox by lifting the handle and then go to center when the handle is lowered? I am wondering about some kind of wear in the linkage. With a load of coal in it I will not be able to see the position of the grates and of course cant burn it with the grates tilted.

Maybe this link can help: Clayton / Hot Blast Mods and Tending for Anthracite
Lightning, drilled, tapped and screwed his 2 in-line grates where they connect due to excessive movement. Others with similar furnaces have done this.

His has the parallel grates in it. I believe 5 or 6 of them. It sounds like he is shaking properly. Just return the grates to flat position (level) when yer done shaking.. no problem..

deepwoods wrote:Another question on the Clayton. When I lift the grate shaker handle the grates tilt to the rear end of the firebox. When I lower the handle the grates tilt toward the front end of the firebox. I need to lift the shaker handle a couple inches to get the grates back to center and not tilted. Are the grates only supposed to tilt to the rear of the firebox by lifting the handle and then go to center when the handle is lowered? I am wondering about some kind of wear in the linkage. With a load of coal in it I will not be able to see the position of the grates and of course cant burn it with the grates tilted.

Ok, I misunderstood the scenario. All is good deepwoods, it sounds like you are describing the shaking action of the grates and this is normal. You can look up thru the ash door and see the position of the grates after a shake down and move them if needed.
I have had a coal jam during a shake and have left the grates in a tilted position for hours until the coal causing the jam got cooked.

After looking at the situation I made a mark on the furnace face behind the shaker lever that indicates when the grates are level when lifting the lever up. It should put my mind at ease about grate position. Yes as mentioned I could always have a look underneath the grates but that involves some serious knee bending so until I get a replacement for the right knee I would just as soon avoid it.
I got the firebox end plates packed with fiberglass insulation per Lightening's instruction for coal burning.
I had 8" thimbles in both flues (basement and upstairs) and got two 6" thimbles as the Hitzer and the Clayton have 6" outlet pipes. Did the upstairs conversion yesterday. I stuffed the 8" with furnace cement, coated the 6" with it and sort of screwed the 6" into the 8" then forced excess into the gap at each end. Going to do the same thing to the basement tonight.
Once the stoves are hooked up I need to think about building a coal bunker in the basement.

Have you been using the Clayton?
How's it coming along?