Making it safer advice on a wood stove opening

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Teachme

New Member
Nov 16, 2021
70
MA
So I posted this in here but didn't get far with it hoping I can get some advice with this post.
I had a wood burning insert (that pervious owner changed to a vc wood stove but left insert) it seems to have a 12 inch outer liner and a 8 inch iner ( not sure what that's called perhaps "Coaxial pipe" ) In any case I Am told it should be changed out to Class a double-wall all-fuel pipe. So I plan to buy class A double walled. Take out the existing 8in leave the 12 inch and run the new 8 inch inner dim double wall pipe though the 12. Also I plan to cut the granite Like so

IMG_1590 lined up.jpg
Black lines I will cut then the top 2inch thick 24" wide granite top plate will go on floor in front.
The red x I will be removing all the wood so that it sits at the same height as the current floor. Then adding cement bored ( durrock or the like) to the back and sides then I was thinking a one inch mettle spacer then anther 3/4 thick durrock. Then ether granite block to match the rest of the fireplace. Or open to ideas? The floor I was planning on using the same granite stone to match.
After all that I am going to try and get my hands on a Blaze King 40
The whole point of this was to make it safer then how they had it with a better stove. All add a few older pics of how it was set up. TYIA for help
IMG_9067.JPG IMG_9069.JPG IMG_9070.JPG
 

begreen

Mooderator
Staff member
Nov 18, 2005
96,254
South Puget Sound, WA
Looks like you inherited a mess. This was not an insert, but a ZC fireplace instead. (sometimes salespeople call this an insert, but that is misleading.) The ZC chimney is not rated to the temperature requirement for a wood stove.

Did you remove the ZC fireplace entirely? If so, the exposed studs are a clearance issue to the flue system and possibly to the stove. The later pictures show galvanized piping coming out of the stove. This is also a no no. The piping should be stainless and probably double-walled stove pipe for reduced clearances.

If you replace the current ZC fireplace chimney with the proper class A chimney, how will it be supported? How does a BK 40 fit into this picture? It is top vented.
 

Teachme

New Member
Nov 16, 2021
70
MA
Looks like you inherited a mess. This was not an insert, but a ZC fireplace instead. (sometimes salespeople call this an insert, but that is misleading.) The ZC chimney is not rated to the temperature requirement for a wood stove.

Did you remove the ZC fireplace entirely? If so, the exposed studs are a clearance issue to the flue system and possibly to the stove. The later pictures show galvanized piping coming out of the stove. This is also a no no. The piping should be stainless and probably double-walled stove pipe for reduced clearances.

If you replace the current ZC fireplace chimney with the proper class A chimney, how will it be supported? How does a BK 40 fit into this picture? It is top vented.

"Did you remove the ZC fireplace entirely? If so, the exposed studs are a clearance issue to the flue system and possibly to the stove. "
Yes as the pic shows the Fireplace is removed. As for the flue Plan to use a stainless double-walled stove pipe and run it in the 12 inch pipe that is there. I belive if any thing this will be over kill. Am I wrong?
I will add a pic the 12inch pipe there now Has flanges keeping it feather then 2inch from any wood far more at most spots.
IMG_1592.jpeg
As for your 2ed ?
"How does a BK 40 fit into this picture?"
As I stated and added the modified picture. My plan is
"
Black lines in Pic are were I will cut then the top 2inch thick 24" wide granite top plate will go on floor in front. Giveing me 4 feet of granite for a harth pad. (and be more behind)
The red x I will be removing all the wood so that it sits at the same height as the current floor. Then adding cement bored ( durrock or the like) to the back and sides then I was thinking a one inch mettle spacer crating a air gap, then anther 3/4 thick durrock. Then ether granite block Min 2.5 inch thick to match the rest of the fireplace. Or open to ideas? The floor I was planning on using the same granite stone to match."
the Bk is top vented but once I make these changes it will give me well over 52" inchs in height to play with. A bk 40 is between
Overall Height (w/ Z1713 Leg Kit) 36 1/2”
Overall Height (w/ Z4815 Base Kit) 32 5/8”
Overall Height (w/ Z3903 Pedestal Kit) 38 3/8” (974 mm)

Did I explain it in a way that makes sense now?
 
Last edited:

kennyp2339

Minister of Fire
Feb 16, 2014
6,697
07462
Still no good, if the stove is going to be recessed into the wooden chase you will need to look up the alcove clearances, doesnt matter what brand stove your going with, each stove has its own clearances set by factory testing.
 

Teachme

New Member
Nov 16, 2021
70
MA
Still no good, if the stove is going to be recessed into the wooden chase you will need to look up the alcove clearances, doesnt matter what brand stove your going with, each stove has its own clearances set by factory testing.
The Bk 40 doesn't have it on there site that I have seen yet any one no what the alcove clearance is on a bk 40? In any case it will not be set in the alcove but just out side it by a few inchs like the old stove was.
 

stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
Download the manual from the site; it has all the info you need
 

begreen

Mooderator
Staff member
Nov 18, 2005
96,254
South Puget Sound, WA
As for the flue Plan to use a stainless double-walled stove pipe and run it in the 12 inch pipe that is there. I belive if any thing this will be over kill. Am I wrong?
We have to be sure that we are talking the same terms here.
Did you mean 6" class a chimney pipe? It also is typically double-wall, but with a high temp insulation layer. If so, that might work, but it is heavy and needs support. How would the chimney pipe be supported?

Stove pipe (aka connector pipe) can only be used in the room envelope, even if it is double-wall. It would not be ok to run stove pipe up the old chimney as a chase.
 

Teachme

New Member
Nov 16, 2021
70
MA
We have to be sure that we are talking the same terms here.
Did you mean 6" class a chimney pipe? It also is typically double-wall, but with a high temp insulation layer. If so, that might work, but it is heavy and needs support. How would the chimney pipe be supported?

Stove pipe (aka connector pipe) can only be used in the room envelope, even if it is double-wall. It would not be ok to run stove pipe up the old chimney as a chase.
Yes Class a double-wall all-fuel pipe. So 8 id with a 10 inch od
Somthing like this 8'' x 48'' DuraTech Stainless Steel Chimney Pipe - 8DT-48SS
SKU: NLE5SP_8DT_48SS
With a support at the bottom and one at the top. And yes I plan to run this pipe though the existing 12 inch pipe. The 12inch is also flanged off all constables.
 

Teachme

New Member
Nov 16, 2021
70
MA
Download the manual from the site; it has all the info you need
I did when I hit ctrl f then put "alcove clearances" nothing came up. but now that I tried it as just "alcove " I see that I don't fall into that as it wont be inside the alcove. not sure how to make this any more clear. But i will try. The alcove is 28 inchs deep I will be putting the stone hearth out 4 feet past that and setting the stove there. the back of the stove will be roughly 36 inch's out from the back of the Alcove.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
I did when I hit ctrl f then put "alcove clearances" nothing came up. but now that I tried it as just "alcove " I see that I don't fall into that as it wont be inside the alcove. not sure how to make this any more clear. But i will try. The alcove is 28 inchs deep I will be putting the stone hearth out 4 feet past that and setting the stove there. the back of the stove will be roughly 36 inch's out from the back of the Alcove.
Your plan sounds fine other than the fact that blaze kings need to go up 2' before an elbow. You will have to go through the wall pretty high up
 
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Teachme

New Member
Nov 16, 2021
70
MA
Your plan sounds fine other than the fact that blaze kings need to go up 2' before an elbow. You will have to go through the wall pretty high up
Yes I read that as well, I plan to run the flu up though the alcove by 45 over and then 45 back straight so no 90s.
Highest legs put it at 38 inchs that gives me over 20 inch's in height to get back to the flu. (32.5 inch for the shorter)
I have been asking around there is a friend of a family member that has the same stove bk 40 he rises 13 inch at best then 90s. He has had it for a 3 or 4 years now with no prob.
"For wall exits, the same suggestion applies. With the addition of the recommendation to use two 45 degree elbows rather than a single 90 degree elbow. The use of two 45 degree elbows will allow for both a smoother transition to the exterior chimney and will also shorten the horizontal run to the outside chimney. A minimum 36” rise is recommended prior to any elbows being used."
I was also thinking of running the class a all the way to the stove as it also says in there manual
"The use of double wall stove pipe does allow for reduced clearances, however most importantly, it helps to keep the chimney warm and improve draft."

Also any one have any experience with these? and perhaps know what befits they add? (as in is it a big game changer?) I don't have a super tight house.
. S.Z3820.BK Leg Ash Pan Kit
4. S.Z1726 / S.Z1726B Fresh Air Kit 4”/3”
 

stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
Double wall stove pipe is not the same as class A.

And the recommendation of a 2-3 ft rise also holds for 45s - those are also elbows. The thing is that 45s are easier on the draft so compromising at the rise is less of a issue.

And all depends on the total height of the chimney. The taller it is the less issues when you compromise on recommendations.
 

Teachme

New Member
Nov 16, 2021
70
MA
Double wall stove pipe is not the same as class A.

And the recommendation of a 2-3 ft rise also holds for 45s - those are also elbows. The thing is that 45s are easier on the draft so compromising at the rise is less of a issue.

And all depends on the total height of the chimney. The taller it is the less issues when you compromise on recommendations.
Is it bad to run class a right up to stove or close to?
I don't belive the 45 will be a problem and one I'm will to gamble on as It will not be a safety concern but more of a problem of getting the fire started. But tbh I don't belive draft will be a problem the flu is taller then most as its a cathedralic room and the fire box is taller then the top of the roof peek. I do realizes this may mean I have to run it longer to warm up b4 I can engage the cat. Dose this sound about right?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
Is it bad to run class a right up to stove or close to?
I don't belive the 45 will be a problem and one I'm will to gamble on as It will not be a safety concern but more of a problem of getting the fire started. But tbh I don't belive draft will be a problem the flu is taller then most as its a cathedralic room and the fire box is taller then the top of the roof peek. I do realizes this may mean I have to run it longer to warm up b4 I can engage the cat. Dose this sound about right?
You can't run 45s in class a 30s are the most you can
 

stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
Is it bad to run class a right up to stove or close to?
I don't belive the 45 will be a problem and one I'm will to gamble on as It will not be a safety concern but more of a problem of getting the fire started. But tbh I don't belive draft will be a problem the flu is taller then most as its a cathedralic room and the fire box is taller then the top of the roof peek. I do realizes this may mean I have to run it longer to warm up b4 I can engage the cat. Dose this sound about right?
I'll leave the class A business to bholler who knows much more. I would not like a shiny class a in my room. Black double wall stove pipe for me.

Regarding the flue; I have a stove in a basement and two stories above that. It's 27'.
How tall is it from the top of your stove to the top of the chimney cap?
 

Teachme

New Member
Nov 16, 2021
70
MA
I'll leave the class A business to bholler who knows much more. I would not like a shiny class a in my room. Black double wall stove pipe for me.

Regarding the flue; I have a stove in a basement and two stories above that. It's 27'.
How tall is it from the top of your stove to the top of the chimney cap?
around 18 to 20 feet.
 

stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
That will likely be fine.
 
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Teachme

New Member
Nov 16, 2021
70
MA
That will likely be fine.
The old set up was a vc vigilant 1977 rear flu went out about 2 feet ish flat then a tee then up and it had great draft. No back drafts. From reading i belive the two feet ish flat plus the tee is far worse then what i hope to change to. Plus all be adding a few feet with new set up. ( lowering stove increasing top hight)
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
The old set up was a vc vigilant 1977 rear flu went out about 2 feet ish flat then a tee then up and it had great draft. No back drafts. From reading i belive the two feet ish flat plus the tee is far worse then what i hope to change to. Plus all be adding a few feet with new set up. ( lowering stove increasing top hight)
Judging how an old rear vent vigilant drafted really has no bearing at all on how a bk king will. With that height it may be fine boing what you propose but it's always a safer bet to just follow the manufacturers suggestions
 
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Teachme

New Member
Nov 16, 2021
70
MA
Judging how an old rear vent vigilant drafted really has no bearing at all on how a bk king will. With that height it may be fine boing what you propose but it's always a safer bet to just follow the manufacturers suggestions
If i could I would trying to do the best i can with what i got to work with. I have no idea what tearing down what i have now and puting in a brick chim would cost but my guss is far more then i would save in heat costs.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
If i could I would trying to do the best i can with what i got to work with. I have no idea what tearing down what i have now and puting in a brick chim would cost but my guss is far more then i would save in heat costs.
No need for a new brick chimney at all.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
If I were asked to do the job I would remove all of the old chimney put in a new class a that comes through above the mantle and connect it with double wall connector pipe. Make an access panel of some sort to cover the old firebox opening so you have access to the bottom of the chimney if you even need it. It would honestly probably be easier to install than what you are proposing and certainly easier to work on.
 
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Teachme

New Member
Nov 16, 2021
70
MA
If I were asked to do the job I would remove all of the old chimney put in a new class a that comes through above the mantle and connect it with double wall connector pipe. Make an access panel of some sort to cover the old firebox opening so you have access to the bottom of the chimney if you even need it. It would honestly probably be easier to install than what you are proposing and certainly easier to work on.
Only two problems with that. One aesthetically be completely ugly.
two you would have to come out even further as the back top is were the flu comes out and at least part of it would hit the granite mantle.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,109
central pa
Only two problems with that. One aesthetically be completely ugly.
two you would have to come out even further as the back top is were the flu comes out and at least part of it would hit the granite mantle.
Uglier than shiny class a angling back directly off the top of the stove? The way I proposed it is the traditional way a stove would have been installed into a fireplace going back to the early 20th century. And I don't understand how that would push the stove forward more.

The way I look at it when I do an install I want to do everything I can to ensure it works as well as possible and that it is easy to service.