Advice on Pipe and Clearance

[martin w]

Hi All,

Been lurking here for many winters, hearing great advice and finding sources.

So I finally registered ‘cause I have something to say (actually ask).

I have an interior chimney containing two 13” x 13” flues. On the other side of this wall is a traditional masonry fireplace connecting to the other flue. The side you see used to be a kitchen and I was told there was a cooking stove connection. 50+ years ago the kitchen was moved and a big wood burner stove was installed into a larger 10” clay flue thimble. When we moved here that was gone and the thimble was covered with a steel plug.

We decided we wanted a fireplace on this side and acquired a Superior zero clearance fireplace. We will build the front and side surrounds with nonflammable materials, with possibly a fan powered air flow running across. My concern is connecting the stove pipe to the thimble and clearances.

1. Stove Pipe. A local shop can build a 10ga 316 SS pipe to connect, in a slow curve with two bends. Would this be better using a double wall pipe? Probably custom?

2. Thimble. Is an insulated thimble (double wall) preferable?

3. Clearances. Side. I am concerned with the distance from the thimble to the side wood. 6 inches from the thimble to the edge of the chimney, then a 2+ inch air gap, then the wood. Is there a best way to handle this? Fill the gap with ceramic insulation? Steel? Double wall pipe?

4. Clearances. Top. The area above the smoke pipe (now sheetrock, that will be removed) will come as close as 9.5 inches to wood where it enters the thimble. What is best way to insulate the ceiling?

I have called in a few chimney people in the area and gotten dramatically different opinions (and costs) on what to do, I would appreciate hearing what you good folk advise.

Many Thanks,

Martin

 

[begreen]

I don't believe what you are proposing is code legal or an accepted installation. Check with Superior and your inspecting authority but to my knowledge 90 degree turns are not acceptable in a chimney pipe for these fireplaces. If this fireplace requires an air-cooled chimney, then absolutely not.

 

[martin w]

You are right, no 90's, could use swivel 45's if double wall. Same idea with a custom single wall pipe.

 

[bholler]

For the most part zeroclearance units cannot be vented into anything but the chimneys they are designed to work with and i dont know of any that are designed to work with a masonry chimney

 

[martin w]

Ok, thanks.
Is there a specific reason you can't run into a masonry chimney?
Heat? Draft? Clearance?

 

[bholler]

Ok, thanks.
Is there a specific reason you can't run into a masonry chimney?
Heat? Draft? Clearance?

These units are designed and tested to work as a whole system with approved chimneys if you change any part of that system the whole system is no longer ul listed and could be unsafe to use and you insurance company would not approve of it at all

 

[Heatsource]

You are right, no 90's, could use swivel 45's if double wall. Same idea with a custom single wall pipe.

steepest offset allowable in any enclosed space is 30* in the US, 45* are allowable in Canada though

 

[begreen]

Swivel double-wall stove pipe is not chimney pipe and not allowed for this unit. 45s are not allowed for chimney pipe. The only way this fireplace can be installed is with the specified chimney pipe. What model is this Superior fireplace?

 

[martin w]

WRT6036RS

 

[begreen]

OK, that confirms that fireplace can only be installed with their proprietary air-cooled pipe. The outer pipe provides cooling air necessary to maintain safe chimney temperatures, while the inner pipe, made of stainless steel, emits the gases out of the fireplace. No substitutes and only 30 degree offsets allowed.

There is no way to legally connect this fireplace to the existing chimney.