adjusting double wall 90s

[tabner]

I just started roughing in my stove pipe, and realized that my Selkirk 90s won't spin. Looked around on here a little bit and it looks like others have had the same problem. Am I correct that a Selkirk 90 degree double wall won't spin to let you adjust the angle?
If so, does anyone know if the Duravent double wall will let you spin the 90s?

 

[tabner]

doing a little research here, it looks like the Selkirk double wall is not adjustable. Duravent says they are (i called customer support). However i can't find a wall thimble product from the Duravent line that works for my application. Below is the Selkirk wall thimble i had planned to use. any input is appreciated.

 

[MTASH]

Cant help with the thimble question, but Duravent double wall elbows are adjustable.

 

[MongoMongoson]

I used to use single wall pipe in the old house so I was used to adjustable elbows. I could change the angles a little to give me my rise, or account for a length of pipe that was not perfect.

With Selkirk DSP, I learned that we now have fixed elbows and adjustable straight pipe. If you are doing a horizontal run, you can still get the small rise required because the joints, even when screwed together, still give you some wiggle. I think you need 1/4" rise per foot of run. Someone please correct me if I am wrong.

If you are trying to make up for imperfect lengths, that is where the adjustable lengths come in. You CAN cut lengths of DSP and crimp with a hand crimper, but it really is a pain.

The adjustable lengths can also help you reduce the number of joints in your stove pipe. I have found that to be important because this stuff fits together so loosely and can be leaky at the joints.

 

[MongoMongoson]

Cant help with the thimble question, but Duravent double wall elbows are adjustable.

That sounds really nice. When I had my chimney installed by a pro, I told him I would do the stove pipe. He "gave" me some Selkirk DSP to get started, so I defaulted to that... and I can get the parts at Menards so it seemed like a good idea.

 

[tabner]

I used to use single wall pipe in the old house so I was used to adjustable elbows. I could change the angles a little to give me my rise, or account for a length of pipe that was not perfect.

With Selkirk DSP, I learned that we now have fixed elbows and adjustable straight pipe. If you are doing a horizontal run, you can still get the small rise required because the joints, even when screwed together, still give you some wiggle. I think you need 1/4" rise per foot of run. Someone please correct me if I am wrong.

If you are trying to make up for imperfect lengths, that is where the adjustable lengths come in. You CAN cut lengths of DSP and crimp with a hand crimper, but it really is a pain.

The adjustable lengths can also help you reduce the number of joints in your stove pipe. I have found that to be important because this stuff fits together so loosely and can be leaky at the joints.

Thanks for the input. My problem is angles more than lengths. Because of my through-the-wall install, (not exterior wall to a class A, but interior wall to a masonry chimney) it seems like the Selkirk thimble pictured above is really the best product for me (plus i already bought it). However I'm trying to minimize the number of 90 degree angles I have, while making sure I meet the required side clearance of the stove, while offsetting the stove backwards a bit to fit nicer in the alcove. it's a bit much using just fixed angles. I emailed duravent and asked if they had a comparable insulated thimble, and they said to just run DVL duravent and screw it directly to that Selkirk thimble pictured above. I may pickup a piece of duravent at my local hardware store and just see how snug the fit is. I think technically all the Selkirk literature is going to say "don't mix and match brands", but if i can get a snug fit and have room to screw it together...it's going to be tempting.
kind of annoying that Selkirk is the more expensive of the two double wall options, yet they don't offer adjustable angles...

 

[tabner]

anybody know of a calculation for how much horizontal run you can get away with? I suppose that's pretty impossible to calculate ahead of time, since your draft is the major factor and that's hard to predict?
There is a way for me to do it nicely with the Selkirk, but i'm going to have basically 24" of double wall vertical off the top of the stove, 90 angle to the left, horizontal run of about 27" (with 1/4" rise per foot)(this is 12" of double wall, plus about 15" of insulated thimble) then 90 degree up the chimney - which is 30 feet of interior 6" square tile/masonry.
I was told by bholler that my chimney should create excess draft, so I'm thinking i might be able to get away with it? or does 27" of horizontal sound ridiculous?

 

[moresnow]

Post some pics to clarify what your trying to get done. Sounds interesting. Alcove with through wall connection.. I'd like to see it. Good luck.

 

[gthomas785]

anybody know of a calculation for how much horizontal run you can get away with? I suppose that's pretty impossible to calculate ahead of time, since your draft is the major factor and that's hard to predict?
There is a way for me to do it nicely with the Selkirk, but i'm going to have basically 24" of double wall vertical off the top of the stove, 90 angle to the left, horizontal run of about 27" (with 1/4" rise per foot)(this is 12" of double wall, plus about 15" of insulated thimble) then 90 degree up the chimney - which is 30 feet of interior 6" square tile/masonry.
I was told by bholler that my chimney should create excess draft, so I'm thinking i might be able to get away with it? or does 27" of horizontal sound ridiculous?

Can you use a 45 degree piece straight off the stove instead of the vertical run?

 

[tabner]

Post some pics to clarify what your trying to get done. Sounds interesting. Alcove with through wall connection.. I'd like to see it. Good luck.

It's a little tricky to show you, since i'm in the middle of the install. But these pics show you the original alcove size (alcove isn't really the right word, i should say "corner"), then the wall removed (current state), and then a diagram of a bird's eye view of the anticipated install layout. I had to remove the rear wall of the corner and move it backwards, in order to get the required 6" of stove pipe clearance on the rear wall, and have the stove pipe line up with the masonry thimble. While doing that, i figured I'll move the wall on the left side as well, a little closer to the chimney, in order to reduce my horizontal run. So I'm in the process of rebuilding the two walls, and trying to get all my dimensions right to work with the thimble and the stove pipe. I'd like to make this corner about 40" square, tile the floor (40" x 40") and tile a few feet up the back wall and left wall. I bought the stove with the rear heat shield and blower to allow install up to 5" from the rear wall (it still needs 13" on the side wall). So i'd really like to push the stove back toward the rear wall, to utilize the heat shield and maximize floor space in the room, but you'll see from the bird's eye diagram, that requires the stove pipe to angle backwards from the thimble location. And of course i have to somehow cover the horizontal distance from chimney, through the wall, and then across the 13" side clearance. I had intended to use a modified 90 off the thimble, with a stretch of pipe running down to a modified 90 just above the stove. So it would be an angled run the whole way.
(to avoid confusion when you see that pic - oil boiler is set to be decommissioned, and disconnected from the flue. Don't worry, only one appliance per flue)

 

[tabner]

Can you use a 45 degree piece straight off the stove instead of the vertical run?

i can, but this makes it so that i cannot set the stove back in the corner at all. Which i will do if i have to, it would just be nicer to slide the stove back about 12" and use what would otherwise be wasted space. I played around with two PVC pipes and some 45 degree angles to confirm that it won't work. If you go 45 down out of the thimble, but angle it backwards, the lower connection is no longer just a 45, it's something quite different.

 

[gthomas785]

i can, but this makes it so that i cannot set the stove back in the corner at all. Which i will do if i have to, it would just be nicer to slide the stove back about 12" and use what would otherwise be wasted space. I played around with two PVC pipes and some 45 degree angles to confirm that it won't work. If you go 45 down out of the thimble, but angle it backwards, the lower connection is no longer just a 45, it's something quite different.

I think I get what you're saying. The thimble is on the left wall, 24" above and 12" forward of the stove collar, right?

To do that with fixed angles I would go up, then forward with a 45, then a 90 to the left. Still leaves you with 27" horizontal so I agree that in this case you may do better with the adjustable elbows.

 

[gthomas785]

Actually I take that back. You can do this with two 45s. Go up ~12" from the stove before the 45, rotated at a 45 degree angle to the left then up to the other 45 which needs to be ~15" out from the wall. Unless I misunderstood your setup.

 

[MR. GLO]

anybody know of a calculation for how much horizontal run you can get away with? I suppose that's pretty impossible to calculate ahead of time, since your draft is the major factor and that's hard to predict?
There is a way for me to do it nicely with the Selkirk, but i'm going to have basically 24" of double wall vertical off the top of the stove, 90 angle to the left, horizontal run of about 27" (with 1/4" rise per foot)(this is 12" of double wall, plus about 15" of insulated thimble) then 90 degree up the chimney - which is 30 feet of interior 6" square tile/masonry.
I was told by bholler that my chimney should create excess draft, so I'm thinking i might be able to get away with it? or does 27" of horizontal sound ridiculous?

All depends on pitch but I single wall pipe and have 4 feet with two adj 90 and angled. Jotul said ok, and permit approved, Some stoves manuals say 3 or 4 feet. When burning my draft is too good. I think going up from stove then adj 90 to the wall then adj 90 to the chimney. I would install a liner. What's the distance from top of chimney hole to the ceiling. One possible problem i foresee is the backside of the wall and maybe ceiling will need to be protected. 6 inch clearance? plus penetrating the wall. I dont think you can use the double wall pipe to go through a wall or ceiling. you will need a rated connection, but i could be wrong. In a basement install I would prefer to have the stove in the boiler room with a door or opening for heat. basements are funky when lighting the stove and can get smoke inside sometimes. Weather and temp condition changes the startup draft. I am assuming your thimble is the rated sorry didn't see that.

 

[tabner]

I think I get what you're saying. The thimble is on the left wall, 24" above and 12" forward of the stove collar, right?

To do that with fixed angles I would go up, then forward with a 45, then a 90 to the left. Still leaves you with 27" horizontal so I agree that in this case you may do better with the adjustable elbows.

yes, you are understanding it correctly. with the one exception that it is actually 34" inches up to the thimble - about 24" of straight vertical up, and then another 10" or so which would consist of the 45 angle coming forwards and a 6" or so piece of pipe coming up into the 90.

Actually I take that back. You can do this with two 45s. Go up ~12" from the stove before the 45, rotated at a 45 degree angle to the left then up to the other 45 which needs to be ~15" out from the wall. Unless I misunderstood your setup.

and i had this thought too, but i actually don't think it'll work. It's very hard to visualize since it's basically imagining 3D dimensions in your head, but i took two 45 degree PVC joints and a piece of PVC pipe and played around and i feel pretty confident it won't work. when you swing the angle of that first 45, it changes the angle you need at the top, to be something slightly different than a 45. again, it's hard to explain, and i could be wrong, but if you play around with some pipes in 3D space i think you'll see it doesn't work.

 

[tabner]

All depends on pitch but I single wall pipe and have 4 feet with two adj 90 and angled. Jotul said ok, and permit approved, Some stoves manuals say 3 or 4 feet. When burning my draft is too good. I think going up from stove then adj 90 to the wall then adj 90 to the chimney. I would install a liner. What's the distance from top of chimney hole to the ceiling. One possible problem i foresee is the backside of the wall and maybe ceiling will need to be protected. 6 inch clearance? plus penetrating the wall. I dont think you can use the double wall pipe to go through a wall or ceiling. you will need a rated connection, but i could be wrong. In a basement install I would prefer to have the stove in the boiler room with a door or opening for heat. basements are funky when lighting the stove and can get smoke inside sometimes. Weather and temp condition changes the startup draft. I am assuming your thimble is the rated sorry didn't see that.

yes, correct, this thimble is specifically designed for this type of install. which is why i want to stick with it. And my clearances are good, i have a masonry chimney with 6" square tile liner, and there are a good 4" of space between the masonry and the house framing all the way up. I believe i only need 2" of spacing. From the thimble up to the roof is around 30 feet, all inside the house envelope. So i anticipate my draft being strong. Am i reading your response correct - you have a 4 foot horizontal run? of single wall?
i think if you are managing that, i should be fine. i would have about 27" of horizontal, with double wall pipe (and actually half of it would be the thimble which is very heavily insulated, so even hotter temps than the double wall).

 

[tabner]

i just took my thimble into tractor supply and matched up the connection with a piece of duravent double wall, per Duravent Tech Support's suggestion - i don't like it. Doesn't fit real snug. I'd have to use an adapter and i don't like the look of it. I doubt it's up to code, and i have kids so no chances. unless someone else has another idea, i think i'll be trying the Selkirk fixed angles and hope my draft is strong enough.

 

[gthomas785]

yes, you are understanding it correctly. with the one exception that it is actually 34" inches up to the thimble - about 24" of straight vertical up, and then another 10" or so which would consist of the 45 angle coming forwards and a 6" or so piece of pipe coming up into the 90.

and i had this thought too, but i actually don't think it'll work. It's very hard to visualize since it's basically imagining 3D dimensions in your head, but i took two 45 degree PVC joints and a piece of PVC pipe and played around and i feel pretty confident it won't work. when you swing the angle of that first 45, it changes the angle you need at the top, to be something slightly different than a 45. again, it's hard to explain, and i could be wrong, but if you play around with some pipes in 3D space i think you'll see it doesn't work.

I get what you're saying. But think about it this way: by adjusting the length of the horizontal, vertical, and diagonal pieces you can force any angles you want, including 45 degrees. I haven't done the trig for your setup but by using telescoping pipe sections you should be able to figure out the lengths you need.

 

[MR. GLO]

yes, correct, this thimble is specifically designed for this type of install. which is why i want to stick with it. And my clearances are good, i have a masonry chimney with 6" square tile liner, and there are a good 4" of space between the masonry and the house framing all the way up. I believe i only need 2" of spacing. From the thimble up to the roof is around 30 feet, all inside the house envelope. So i anticipate my draft being strong. Am i reading your response correct - you have a 4 foot horizontal run? of single wall?
i think if you are managing that, i should be fine. i would have about 27" of horizontal, with double wall pipe (and actually half of it would be the thimble which is very heavily insulated, so even hotter temps than the double wall).

Its 4 foot at a 20 degree angle or so...but as long as you have the pitch per foot your ok...single wall but im dealing with concrete walls...

You need to know your ceiling height, thimble height in room from floor and to ceiling. plus stove height...This would help....

I think the room needs a separate thimble and the chimney needs a sperate thimble unless you can find one to do both and is adjustable (expensive)_ I dont think you cant just run double wall from the masonry thimble into the room between the walls and place a ring on it. Ask Duravent. Plus that masonry thimble might need to be connected to a liner with a tee so you can clean out. Are you leaving access to the small black door under the bottom of the chimney?

 

[tabner]

Its 4 foot at a 20 degree angle or so...but as long as you have the pitch per foot your ok...single wall but im dealing with concrete walls...

You need to know your ceiling height, thimble height in room from floor and to ceiling. plus stove height...This would help....

I think the room needs a separate thimble and the chimney needs a sperate thimble unless you can find one to do both and is adjustable (expensive)_ I dont think you cant just run double wall from the masonry thimble into the room between the walls and place a ring on it. Ask Duravent. Plus that masonry thimble might need to be connected to a liner with a tee so you can clean out. Are you leaving access to the small black door under the bottom of the chimney?

about 64" to the center of the masonry thimble, from the floor. Minus about half an inch of tile i'm putting down. Stove top is 30" high. Ceiling i'm not sure, pretty sure it's between 7 foot and 7.5 foot. This thimble is designed to do exactly what i am trying to do, you can pull up the install manual online, but it comes apart in two pieces and it is specifically designed so that one side bolts into the masonry chimney (comes with cement screws and rockwool), and then it is about 3" thick of insulated metal, plus a 1" air space all the way around, with a shroud and a radiator shield, etc, to get it through the combustible wall. just gotta connect your stove pipe up to it.
But you are correct about thimbles with regard to Duravent, i don't think they have a product like this - all their thimbles want Class A to run horizontal through the wall, which i don't want to do. hence why i am trying to stick with this Selkirk thimble.

 

[tabner]

I am amazed i just got an emailed response from Selkirk saying that i can attach any other brand of stove pipe to their thimble, as long as clearances are met. For liability reasons, i am amazed they put that in writing.
regardless, when i lined up the duravent DVL with my thimble i really didn't like the look of the connection. I ordered the 45 degree Selkirk and a 6" piece. I'm going to try the install per Gthomas785 breakdown above. a 45 and a 90 to the left. with 26" of horizontal run on as much pitch as i can get in it. and hope my 30 foot chimney compensates for the draft. if i have draft problems, i'll know where to start troubleshooting, and i'll try it a different way.

 

[MR. GLO]

Thimble is about 64" to the center of the masonry thimble, from the floor. Minus about half an inch of tile i'm putting down. Stop top is 30" high. Ceiling i'm not sure, pretty sure it's between 7 foot and 7.5 foot. This thimble is designed to do exactly what i am trying to do, you can pull up the install manual online, but it comes apart in two pieces and it is specifically designed so that one side bolts into the masonry chimney (comes with cement screws and rockwool), and then it is about 3" thick of insulated metal, plus a 1" air space all the way around, with a shroud and a radiator shield, etc, to get it through the combustible wall. just gotta connect your stove pipe up to it.
But you are correct about thimbles with regard to Duravent, i don't think they have a product like this - all their thimbles want Class A to run horizontal through the wall, which i don't want to do. hence why i am trying to stick with this Selkirk thimble.

So the access door to the chimney will be blocked by the new walls? If so how do you clean the chimney with and without using a liner?

My thimble to the floor is 58" FYI The ceiling panels above that stove will be very hot with a 7 foot ceiling. Using Double wall will help with clearances. But without seeing the stove clearances to walls its tough to picture. But two adj 90 and a starter damper section (or small starter pipe) and a telescoping pipe will work. but you will need to move or swing the stove for the clearances. You said Selkirk doesnt have those adjustable 90. If you plan on using your Selkirk I think you will need to be moving redesigning the walls to obtain clearances for fixed 90 and 45.

But the chimney is that just stack of blocks or is it lined with tiles of some sort?

 

[tabner]

So the access door to the chimney will be blocked by the new walls? If so how do you clean the chimney with and without using a liner?

My thimble to the floor is 58" FYI The ceiling panels above that stove will be very hot with a 7 foot ceiling. Using Double wall will help with clearances. But without seeing the stove clearances to walls its tough to picture. But two adj 90 and a starter damper section (or small starter pipe) and a telescoping pipe will work. but you will need to move or swing the stove for the clearances. You said Selkirk doesnt have those adjustable 90. If you plan on using your Selkirk I think you will need to be moving redesigning the walls to obtain clearances for fixed 90 and 45.

But the chimney is that just stack of blocks or is it lined with tiles of some sort?

yes, sorry, you did ask about the cleanout door and i didn't comment. I plan on leaving enough room behind that wall on the left that i can get in there with a shopvac. My roof is not bad and i don't mind going up on it, so i would clean with my soot eater down from the top and then stick a shopvac nozzle through the cleanout door.
I'll double check the ceiling height, but pretty sure i'll exceed the 8" double wall clearance.

 

[tabner]

But the chimney is that just stack of blocks or is it lined with tiles of some sort?

sorry, i keep neglecting to answer the second question. Yes, it's 6" square tile chimney, inside the cement.

 

[tabner]

random thought, somewhat outside-the-box here: how involved is it to build a non-combustible wall? and how much does that reduce your clearances? Since i'm rebuilding both walls anyways, i could build that wall on the left with metal studs, then i intend to do Duroc with tile anyways. At that point i could shimmy the stove up to the left wall, maybe 5" off the wall or so? At that point i could remove the 12" horizontal run. it would just be the length of the thimble coming out of the chimney (which is horizontal i can't get rid of anyways) and then a 90 down and a 45 back. same basic stove pipe design as discussed above, but 12" less horizontal run. Would bring the total horizontal run down to about 16".