figuring the flue

fishinAK · Aug 24, 2006

hey guys Im still trying to decide how I am going to connect my new F3 CB to my existing 8 inch class A chim. My latest idea is to (from top down) 8 inch chim - chim connector- 8"-6" reducer - 12 ' of 6" dsp stove pipe - Tee - stove connector into rear vent of stove.
So what do you think of that plan?
My questions reguarding this plan is. Does the Tee need to be supported anyway? And can I connect the reducer directly to the chimney connector.

My other idea is to (top to bottom again) 8" existing class A chim - chim connector - 45 elbow - 45 elbow - 8"-6" reducer - 6" dsp directly to top exit of stove.
The purpose of the 45s is to give me a little ofset to move the stove fwd off the backwall a bit.
Questions reguarding this plan is how would I clean this? Do I just have to disconnect the 45s each time? and when cleaning is it ok to brush the soot back int the stove?

Please any and all advice is appreciated. I know you need pics and I will try to remember to take some and post them.

webbie · Aug 24, 2006

fishinAK said:
hey guys Im still trying to decide how I am going to connect my new F3 CB to my existing 8 inch class A chim. My latest idea is to (from top down) 8 inch chim - chim connector- 8"-6" reducer - 12 ' of 6" dsp stove pipe - Tee - stove connector into rear vent of stove.
So what do you think of that plan?
My questions reguarding this plan is. Does the Tee need to be supported anyway? And can I connect the reducer directly to the chimney connector.

My other idea is to (top to bottom again) 8" existing class A chim - chim connector - 45 elbow - 45 elbow - 8"-6" reducer - 6" dsp directly to top exit of stove.
The purpose of the 45s is to give me a little ofset to move the stove fwd off the backwall a bit.
Questions reguarding this plan is how would I clean this? Do I just have to disconnect the 45s each time? and when cleaning is it ok to brush the soot back int the stove?

Please any and all advice is appreciated. I know you need pics and I will try to remember to take some and post them.

I would usually do it this way - reduce right at the pipe adapter on the bottom of the class A.

Yes, you can usually brush soot back into the stove or the pipe nearby - but some people disconnect the pipe and tie a trash bag over the end of the pipe- then burch down into it.

Does the tee have to be double pipe? If single or interior double I doubt it would need additional support as long as everything was screwed together.

fishinAK · Aug 24, 2006

ya I am pretty sure the Tee would have to double wall. as it would be 3 inches in frount of a 6 inch thick vented brick wall. Or am I wrong about that too? do I even need double wall? How far out away from the wall would the pipe have to be? Like I said the wall is 6 inch vented brick. Maybe I could use single wall. opinions?

MountainStoveGuy · Aug 24, 2006

If were splitting hairs here, double wall connector pipe has a 6 inch clearance, a vented brick wall with a one air space gives you a 1/3 reduction in pipe clearance..... Single wall is out of the question, technically the double wall will need to be 4" away. the stove connection on the 3cb can be intresting, to hook a double wall t back there required a special adapter the customer made. Have you tried to dry fit the T yet?

webbie · Aug 24, 2006

fishinAK said:
ya I am pretty sure the Tee would have to double wall. as it would be 3 inches in frount of a 6 inch thick vented brick wall. Or am I wrong about that too? do I even need double wall? How far out away from the wall would the pipe have to be? Like I said the wall is 6 inch vented brick. Maybe I could use single wall. opinions?

Wait....

I thought a vented wall was a 2/3 (66%) reduction to the original combustible wall. If true, the single pipe could be used.

Let's look it up.....

Yes, that's what my NFPA chart says.

So, if the pipe was originally 18", it would be 6" from the original wall - and he has 9". In other words, only a 50% reductions.

So, based on:
https://www.hearth.com/content/images/uploads/nfpachart1.jpg

It would be OK.

PS> This is a stove chart, I have to look up the pipe reductions, they may differ. But 50% sounds doable, as that is the same that pipe heat shield produce.

MountainStoveGuy · Aug 24, 2006

Webmaster said:
fishinAK said:

ya I am pretty sure the Tee would have to double wall. as it would be 3 inches in frount of a 6 inch thick vented brick wall. Or am I wrong about that too? do I even need double wall? How far out away from the wall would the pipe have to be? Like I said the wall is 6 inch vented brick. Maybe I could use single wall. opinions?

Click to expand...

Wait....

I thought a vented wall was a 2/3 (66%) reduction to the original combustible wall. If true, the single pipe could be used.

Let's look it up.....

Yes, that's what my NFPA chart says.

So, if the pipe was originally 18", it would be 6" from the original wall - and he has 9". In other words, only a 50% reductions.

So, based on:
https://www.hearth.com/content/images/uploads/nfpachart1.jpg

It would be OK.

PS> This is a stove chart, I have to look up the pipe reductions, they may differ. But 50% sounds doable, as that is the same that pipe heat shield produce.

That pesky NFPA211, sorry for the bad info AK, craig, i think the same applies for pipe, 66% reduction.

fishinAK · Aug 24, 2006

So then single wall would be ok? But what about where it comes directly out of the chim. it is less than 18 in to the the chim. is the chimney connector double wall? Can I get a 8"-6" reducer that will reduce directly to single wall?

Shane · Aug 24, 2006

Can you post a picture? From what your explaining you'll be ok with single wall. You have nothing directly the the rear of the pipe that is combustible correct? That non-combustible is atleast 18" wide correct? If so then your fine to install the single wall pipe.

webbie · Aug 25, 2006

fishinAK said:
So then single wall would be ok? But what about where it comes directly out of the chim. it is less than 18 in to the the chim. is the chimney connector double wall? Can I get a 8"-6" reducer that will reduce directly to single wall?

From the info I'm guessing that the brick only goes up so high and therefore the pipe is closer to the wall at the level where it hits the chimney. It should be 18" - since you don't appear to have that, you need a pipe heat shield for that portion of the pipe that sticks above the brick. This lowers the clearance to 9"

elkimmeg · Aug 25, 2006

Nfpa reduction is up to 66% in certyaint cases but does not allow deductions less that 12" which case MSG was righ 66% would alow a reduction od 36" to m12" but NFPA will not allow a decuction less than 12" However manufactures specs will allow further reduction if the stove and heat shield is so listed and tested ant the double wall pipe as well There is two parts of the equasion the stove placement and the vent pipe The stove coul;d be 12" but if single wall vent pipe is used then the p single wall clearance issues have to be addressed meaning eventhough the stove is listed for 12 " single wall make that 18" a connector shield or double wall is needed to use the stove setup to 12"

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