What size hole to drill for 6" chimney?

Traveler004

New Member
Sep 18, 2019
9
Quebec
Hi guys,
I've scratched my head on this image for a good hour. It makes no sense to me.
wallthimble.png



There zero chance B is the inside diameter and 17" if A is the outside square and is 10-1/8" it's just physically impossible. I don't have my chimney yet but i need to cut the hole for it. So I need to know what size diameter hole i need to fit this thimble in nicely. It's not something I can fix later as I'm having someone with a core drill come and do it. This diagram from Selkirk doesn't make me comfortable. What i know is the inside diameter of chimney is 6" I can't even find the outside diameter info on it but i'm assuming is 2" of insulation and might be 8" so if you add 1/8 for 2 layers of steal and another 2" for air clearance, i could guess that it's the 10-1/8 and maybe they just got the diagram wrong. But like i said. I can't make a mistake on this one so asking for anyone who has already installed one of these, what size hole did you drill?
 

begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
Looks like the artist messed up. I suspect that dimension B is the OD of the round inside trim, not the ID. A is the OD of the outer sleeve. It's amazing that Supervent hasn't updated or had a new catalog in over a decade where this could be corrected.

If you are core drilling through a concrete foundation you don't need the thimble to pass the chimney pipe coming from the outdoor chimney tee unless wood framing will be right next to the pipe. It is designed for maintaining 2" clearance to combustibles.
 

Traveler004

New Member
Sep 18, 2019
9
Quebec
Looks like the artist messed up. I suspect that dimension B is the OD of the round inside trim, not the ID. A is the OD of the outer sleeve. It's amazing that Supervent hasn't updated or had a new catalog in over a decade where this could be corrected.

If you are core drilling through a concrete foundation you don't need the thimble to pass the chimney pipe coming from the outdoor chimney tee unless wood framing will be right next to the pipe. It is designed for maintaining 2" clearance to combustibles.
I suspect this also but just wanted to be sure. It's possible they do have an updated catalogue, i searched for the UPC code to get the model number then searched for the model number to get the correct catalogue. Neither retailers nor manufactures are making it easy.

I am going through concrete and I do not have framing or insulation on the inside. In this case you are saying I should just drill whatever the OD of the 6" chimney pipe is? Which I still don't know. If anyone out there has a supervent chimney can you share with me the exact OD?
 

begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
Yes, if there are no combustibles within 2" after the work is finished then you can just cut the opening hole slightly larger then the widest diameter of the pipe and silicone the gap inside and out after it is in place.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
I heard back from Selkirk. They say that for the Supervent JM6WT thimble one needs to cut a 12 3/8" hole. As noted, you don't need it for an entirely non-combustible installation as long as the chimney pipe is 2" away from any combustible (including wall finish).
 

Traveler004

New Member
Sep 18, 2019
9
Quebec
I heard back from Selkirk. They say that for the Supervent JM6WT thimble one needs to cut a 12 3/8" hole. As noted, you don't need it for an entirely non-combustible installation as long as the chimney pipe is 2" away from any combustible (including wall finish).
Thank you for that. No where in the instructions does it say that.
My wall finish is actually aerated cement so it's not combustible. And I assume this 2 inch space in thimble will let a lot of cold in when the stove is not on, so I'm going to go with 10-1/8 and just put the chimney pipe straight through.
Thank you so much for being here and sharing your time and knowledge. This forum is amazing. Without it I'd be lost between a paper storm of poorly written specs and incorrect instructions and youtube videos
 

begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
Traveler004 is this for 6" chimney pipe or 8" chimney? 6" Supervent has an 8" OD. For 6" I would think the hole would be more like 8.25" to clear the 8" OD pipe.

May I suggest that you not proceed with the core bore until after you have all the chimney components?
 

Traveler004

New Member
Sep 18, 2019
9
Quebec
Traveler004 is this for 6" chimney pipe or 8" chimney? 6" Supervent has an 8" OD. For 6" I would think the hole would be more like 8.25" to clear the 8" OD pipe.

May I suggest that you not proceed with the core bore until after you have all the chimney components?
it's 6 with 2" of insulation the to total is 10" diameter. I actually took my measuring tape to the store to verify. lol
Under optimal circumstances I would wait.
there is 2 different supervent products and one has 1" of insulation and mine has 2". Like i said, they aren't making it easy.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
Hmm. Supervent is 8" OD. Are you sure the other pipe was Supervent and not DuraPlus? What store is this? Home Depot?

This is Supervent. Dimension C is the OD.
Screen Shot 2019-10-08 at 12.16.18 PM.png
 

ShawnLiNY

Member
Dec 13, 2018
197
Ny
As above perhaps you measured triple wall if you got 10" I cored my chimney with an 8" bit I needed to grind off the rolled flange in order for the pipe to slide through ( welded it after it was in place ) not something every homeowner is capable of . Go with 8 1/2 " if possible .
 

Traveler004

New Member
Sep 18, 2019
9
Quebec
As above perhaps you measured triple wall if you got 10" I cored my chimney with an 8" bit I needed to grind off the rolled flange in order for the pipe to slide through ( welded it after it was in place ) not something every homeowner is capable of . Go with 8 1/2 " if possible .
Yikes, I did see the flange and measured it. i thought i would be ok but I will certainly take your advice and cut closer to 10-1/2
 

Traveler004

New Member
Sep 18, 2019
9
Quebec
Hmm. Supervent is 8" OD. Are you sure the other pipe was Supervent and not DuraPlus? What store is this? Home Depot?

This is Supervent. Dimension C is the OD.
View attachment 248838
Yep. There are 2 supervents. Model JSC is the specs you posted and model JM here. I had to check the UPC code to see which i had. This was enough confusion for me and why I took the trip to the store and actually put my hands on it and measured it to make sure I knew which was which. The stores do not say or advertise this. They just say SuperVent. If I have one grip about this whole process it's that stores (all of them it seems) don't supply people with the manufactures model number and CORRECT name. I actually had to have a long conversation with the stove manufacture just to find out which of their stoves was being sold by a store, because the store was selling this stove under a DIFFERENT name?!?! I was not impressed.
In fact the correct name here is also a problem. This isn't supervent it's supervent 2100. I can only assume the people at these stores are unaware of these. perhaps years back there was only one supervent product and then there was 2 and then they started ordering this one and neglected to tell anyone. I can see how it can happen but its more than 3 stores so far.
And it might be wise for manufactures to realize these issues happen and not to name their products so similar it makes difficult to distinguish between them. Just good business practice.

supervents.png supervent2100.png
 
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begreen

Mooderator
Staff member
Nov 18, 2005
78,568
South Puget Sound, WA
This is the first time I have seen that chimney. Appears to be a Canadian product. Why would one want to use the JM over the JSC which is less bulky and seems to be higher rated? Price?
 
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Traveler004

New Member
Sep 18, 2019
9
Quebec
This is the first time I have seen that chimney. Appears to be a Canadian product. Why would one want to use the JM over the JSC which is less bulky and seems to be higher rated? Price?
I don't know. JM it is what they sell here as supervent. As i said, no one is making a distinction. I did not realize JSC was an american product. Perhaps this is why everyone is just calling it supervent. Perhaps JSC doesn't met some Canadian regulation and JM does? I don't know. I know DuraTech has a product specially for the more stringent Canadain reglulations called DuraVent Canada but oddly enough I could only find it sold in the U.S. Another bizarre story. That product was actually my first choice, but couldn't source it here. ICC was my second choice, No comment on that one. So i ended up getting my last choice and it was on sale so that made it better. It's been quite a learning curve and experience for sure.
 

blades

Minister of Fire
Nov 23, 2008
3,296
WI, Leroy
about same aquring a vechile that was built at the begining of a model change - Parts do not match what is used 6 mo. later as they use up stock on hand from previous model(s) when ever possible. Sometimes even the serial # does not help getting a matching part, or the so called replacement part isn't even close.