Short Chimney

[Joe Bruno]

Hi. I have a woodstove (Hearthstone) that exhausts into a 6" SS liner that is installed inside an existing masonry flue. From the back of the stove exhaust to the top of the flue it's just over 12 feet. Unfortunately, that is not quite tall enough, so it lacks a powerful draft. It works okay, but not great.

I was thinking to add four feet of metal chimney pipe as that would bring it up to spec. and should make a big difference. I am wondering how to achieve this. Obviously, a metal pipe cannot be attached to the liner. I would have to attach a metal receiver to the top of the masonry chimney, and then to connect the new pipe to that receiver. I do not see any such devices/brackets/etc. on the websites of chimney pipe manufacturers to do this. If the attachment was strong enough it might not need any guy wires. But I could guy the four foot section to the bluestone chimney cap if necessary.

An additional consideration is that I would have to take it down to sweep the liner. So it has to be removable. Unfortunately, I cannot sweep this flue from the bottom up.

If anyone has a great idea please share. Thank you, Joe

 

[moresnow]

Post pics of your existing stove to liner connection as well as the current liner top termination.

Google chimney transition plate.

 

[bholler]

Hi. I have a woodstove (Hearthstone) that exhausts into a 6" SS liner that is installed inside an existing masonry flue. From the back of the stove exhaust to the top of the flue it's just over 12 feet. Unfortunately, that is not quite tall enough, so it lacks a powerful draft. It works okay, but not great.

I was thinking to add four feet of metal chimney pipe as that would bring it up to spec. and should make a big difference. I am wondering how to achieve this. Obviously, a metal pipe cannot be attached to the liner. I would have to attach a metal receiver to the top of the masonry chimney, and then to connect the new pipe to that receiver. I do not see any such devices/brackets/etc. on the websites of chimney pipe manufacturers to do this. If the attachment was strong enough it might not need any guy wires. But I could guy the four foot section to the bluestone chimney cap if necessary.

An additional consideration is that I would have to take it down to sweep the liner. So it has to be removable. Unfortunately, I cannot sweep this flue from the bottom up.

If anyone has a great idea please share. Thank you, Joe

I know ventis and Jeremiahs make transition/anchor plates

 

[begreen]

DuraVent offers this solution for transistioning to DuraTech chimney.



The transition plates are sold in different dimensions according to the chimney top size. The slip connector supports the liner with a band clamp.

 

[Joe Bruno]

Thank you all. "Transition Anchor Plate" and "Chimney Anchor Plate" are great suggestions. Now I know what it is called in the trade. The pic of one such plate that one of you posted here is similar to what I had drawn up and was considering having fabricated locally. It would be much better to get one from a maker of whatever pipe I use to extend the flue. All the kinks would have been worked out.

Moresnow asked for a pic of the chimney top. Raining now, and dark, but it is a single slab of bluestone, 30 x 46 x 2 inches. Two clay-tile liners rise through the bluestone and extend 4" above the plane of the stone; one liner is 10x10 for the boiler, and the other is 10 x14 for the fireplace. The 10x14 is the one that has been lined with a 6" SS flex liner. The 10x14 flue tile is capped with a flat plate that has a 6" dia. nipple in the middle to allow the liner to come up through it. Before the plate was installed the company who did the job packed the space around the SS flex liner with some sort of rockwool insulation. The nipple was slathered with silicone caulk before it was lowered into place over the flex liner (that closes the small space between the nipple and the liner). The nipple has an indentation near the top, this provides a precise place to fasten the SS band clamp that secures the rain cap and completes the installation.

It seems the kind of Anchor plate pictured here would mean I'd have to cut off the 4 inches of clay-tile flue liner that sticks up above the bluestone. With a grinder that should be no problem. I will Google these tomorrow and see what is available.

As for the connection at the stove. I used the rear exit option on the Hearthstone stove. Per the photos I am hoping to attach, a 6" SS nipple about 12" long attaches the back of the stove to the SS tee behind the pickled steel surround you will see in the photos. The tee attaches to the SS liner with the built-in clamps. On the bottom of the tee there is a 45 and a cap that I remove to collect the crumbs when cleaning the liner.

Thank you all again.