Hearthstone Top Flue Exit

[sarahf]

I have a heritage hearthstone and am in the process of installing the stove pipe. I am using Selkirk double wall pipe. Everything seems great except that I don't understand what is up with the screws to attach the stove adaptor pipe to the top stove flue. Am I supposed to screw all the way through into the interior sleeve of the double wall pipe to attach the pipe to the stove? If I don't screw into the interior sleeve, the screw would just sort of hang there and do nothing. I don't feel comfortable letting the pipe just "sit there" as I have been told to do. And if I screw through the interior sleeve doesn't that cause a leak in the pipe? I am starting to get a little impatient to get this fire going - am so excited to see this beautiful monster at work.

Thanks for the help!

Sarah

 

[BrotherBart]

A lot of installers don't put screws in the double wall at the flue collar if there are several sections of pipe with screws in them sitting on top of that section. With that big hunk of rock stove under it and the weight of the pipe sections above it, it ain't going anywhere except in maybe the biggest earthquake Maryland will ever see.

If you want to you can drill through the pipe and the adapter and install screws. Any draft leakage will be very minimal. The pain in the backside will be lining up the holes again after you take the pipe off to sweep it.

 

[Buck1200]

I have double wall pipe on my heritage which I installed 3 years ago. The bottom of the pipe should fit snugly within the stove's flue collar. You then screw through the clearance hole in the flue collar to the stove pipe (as you surmised).

With stove pipe, you do get lots of miniscule leaks at each screw and slip fit connection, but as long as you have decent draft they don't really amount to anything significant in terms of reduced flue gas flow rates or temperature.

And just so we're clear- the leaks I mention are from the room INTO the pipe. Smoke will never leak out as long as you have decent draft and have otherwise installed everything correctly. Good luck!

 

[Highbeam]

You aren't supposed to screw the double wall to the stove collar. Single wall yes, but you can't do it with double wall. Of course you can.... meaining that you can run some goofy big long screw through a goofy big hole in the side of your nice pipe, but you're not supposed to. People talk about it but I've been looking for a long time for a photo of it actually being done and have never seen it. Perhaps one of the little stove collar adapters would make this less painful.

 

[sarahf]

Thanks for all the info. I went ahead and assembled the pipe without screwing it into the stove collar (I figured I could always screw it in later if I need to). What I had read/heard somewhere was that it needed to be screwed in because if there is a creosote fire the pipe will shimmy (where it is not screwed in) and can cause the rest of the pipe to break. Is that nonsense?

Sarah

 

[linckeil]

You aren't supposed to screw the double wall to the stove collar. Single wall yes, but you can't do it with double wall. Of course you can.... meaining that you can run some goofy big long screw through a goofy big hole in the side of your nice pipe, but you're not supposed to. People talk about it but I've been looking for a long time for a photo of it actually being done and have never seen it. Perhaps one of the little stove collar adapters would make this less painful.

highbeam, my mansfield has 3 pre drilled holes on the flue collar. my double wall metalbestos damper (same as a double wall stove pipe adapter but with a plate in it) has 3 pre drilled holes on the outside wall. this leads me to beleive that both the stove and chimney manufacturer want this connection to be secured with screws. so when i installed my stove a couple of weeks ago, i secured this connection and believe it is the correct thing to do. am i understanding you correctly when you say this connection should NOT be secured?

 

[Highbeam]

Hi linckeil,

If you can do it without causing more harm than good, even considering aesthetics, then do it. It won't harm anything. Hearthstone told me that the holes in Simpson brand double wall pipe will not line up with the inner stove collar holes anyway. Here's the question for you though... how did you deal with the air gap between the outer shell of the double wall pipe and the inner wall at the stove collar. Did you crush the outer shell? did you leave the screws loose? Drill a big honking hole in the outer shell to allow a driver? I wonder if by using the damper adpater you were able to solve the problem somehow. See, the adapter is meant to be "attached" to the stove collar so some concession might have been made. The holes in the stove collar are for connection to single wall pipe and most brands have them since the typical installation is with single wall pipe.

Regardless, the predrilled holes in double wall pipe are to allow the pieces of pipe to be secured together and not necessarily to attach to the stove collar. The holes will line up with the other double wall sections but not with the stove collar for some reason.

I questioned this issue with my pro installer and with the inspector. They both thought I was nuts and asked, how would you even do it. Seems that the pipe isn't coming out from between the stove and ceiling since the length is fixed by screwing the slip joint pieces together. If the stove doesn't go down and the ceiling doesn't go up then there is no way to get the pipe uninstalled.

All bets are off with a rear flue exit. Those guys would really want to screw onto the stove collar. Usually though, the rear exit guys are into fireplaces and then use single wall.

I was really wanting each joint to be screwed. Even my class A in the attic is screwed. I haven't been able to find anyone here or in the real world that has actually done it. My last hope is for the adapter to solve this issue.

 

[linckeil]

Ok, here’s what I did....... The 3 pre drilled holes on the outside of the double wall metalbestos damper lined up perfectly with the 3 pre drilled holes in the stove collar. However, the stove collar holes were much larger than the damper holes. So large that it needed a bolt, not a sheet metal screw. So with a ¼” – 20 tap, I tapped the 3 holes in the stove collar. Now the 3 holes are ready to accept a bolt. With a drill, I enlarged the 3 holes in the outside wall of the damper so that the bolt can fit through. I then cut the 3 ¼” – 20 bolts down to a shorter length. They are cut to the thickness of the flue collar plus the thickness of the outside wall of the damper, plus the thickness of a flat and lock washer I wanted to use. This way the bolt runs through the outside wall of the damper and threads into the stove collar. The threads of the bolt fully engage the threads I tapped into the stove collar. But the inside wall of the damper is not penetrated nor does it come into contact with any of the bolts as they are cut to length to prevent this. I used stainless steel bolts and washers and I think that both functionally and aesthetically it is great.

The stove collar on the Mansfield is thick – thick enough to allow me to tap a hole. The outside wall of the damper fits snuggly on the outside of the stove collar and the inside wall of the damper fits snuggly on the inside of the stove collar, so there is no worries of airspace or of any crushing of the pipe to make it fit. I’d imagine all 6” Hearthstone stove collars are constructed the same as what is on the Mansfield, but I don’t know. And I’d also imagine the stove pipe adapter and damper kit both fit the same way. I looked at both when purchasing my chimney setup and they sure looked identical (with the exception of the plate in the damper of course).

I am using the double wall telescopic length in between my damper and the stainless chimney. So this allows me to first secure the damper to the stove collar, then expand the telescopic length down to the damper, where it is secured with 3 sheet metal screws.

I hope I am explaining this well. I try to snap a few pictures tonight when I get home.

 

[linckeil]

Here are the pics.....

 

[Highbeam]

Wow, that doesn't even look like double wall. The outer shell of my Simpson pipe looks to be much farther away and it also hangs down much closer to the top of the stove. Either way, good job on making it work. So as I understand it you only threaded the bolts in a distance equal to the thickness of the collar material and you didn't actually torque anything? Good job. I would like to make my setup equal to yours even if I didn't get the collar screws in. I wonder if the adapter with or without the damper is the trick here. The actual tech at Hearthstone told me that the screw holes won't line up and that I might get one to work but need to drill the other two.

 

[linckeil]

thanks. the 3 stainless bolts are torqued. they are cut short so that they can be torqued and fully engage the threads i tapped without interfering with the inside wall of the damper. the bolts are cut to the thickness of the stove collar plus the thinkness of the outside wall of the damper, plus the washers i used. this ensures i can torque the bolts without the bolt penetrating the inside diameter of the stove collar.