To Insulate or Not Insulate a Flexible Liner - That is the question!

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Does that cap have a hinge? The cap I saw on line had a visible hinge and the cap appeared somewhat skewed. It appears they have improved the design as your cap appears straight across and clean. Nice job. Thanks for sharing.
 
My chimney runs up the center of the house from the basement and was an open fireplace in good working condition. I put in an insert with an uninsulated flex liner.
I always had smoke issues so last year I tore out the liner and installed a new insulated liner and can say it made a big difference.
Like I said it is an interior chimney any people say they are warmer.
So I am a believer in the insulation.

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That is what I was told as well and, the thought of saving an additional $300 sounded great. BUT, my understanding is that you cannot allow this liner to touch the chimney flue lining if you have 4 inches or less of masonry and the flue liner and seals are intact.
 
Yeah, that chimney cap is a lot higher than mine.
 
Purchased the pieces alacarte. I actually got the top plate from Woodlanddirect.com I told the sales tech on the phone what I had and what I needed and that is what he sent. I was unimpressed. The hidden plate is galvanized. I used silicon under it and then silicon on top and the second top plate on top that. My cap is not hinged because they said they did not have a 13x18 hinged cap. Get one if you can, they are very nice.

There is a little gap between the liner and the top plate. there is a approx 1inch lip where the clamp sits so a very minimal amt of rain would be able to enter and even then it'd have to be blowing rain since my cap covers the entire clay flue.
 
BUT, my understanding is that you cannot allow this liner to touch the chimney flue lining if you have 4 inches or less of masonry and the flue liner and seals are intact.
That is not even close to right. To be a useable chimney you need 4" nominal masonry walls which is 3.5. Any less than that it is unusable. Then you need clearance from the outside of the masonry to any combustible material. 1" for external chimney 2" for internal.If you dont have that you need insulation.
 
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That is not even close to right. To be a useable chimney you need 4" nominal masonry walls which is 3.5. Any less than that it is unusable. Then you need clearance from the outside of the masonry to any combustible material. 1" for external chimney 2" for internal.If you dont have that you need insulation.
Ok. Sorry, I did not convey that correctly. Anyway, my setup requires the insulation. Thanks for clarifying this. It appears, to me, that the concept of insulating the flex liner is being portrayed more as an economical option rather than a safety requirement, if applicable.
 
Ok. Sorry, I did not convey that correctly. Anyway, my setup requires the insulation. Thanks for clarifying this. It appears, to me, that the concept of insulating the flex liner is being portrayed more as an economical option rather than a safety requirement, if applicable.
There i the safety issue but there is also a big performance increase as well.
 
I have already decided I will insulate the liner. I am going to use a T and I guess I must abandon my desire for the hinged rain cap. If I comprehended the directions correctly, it is recommended the T of the Olympia Heavy Flex liner "Armor Flex" should be secured and supported within the chimney (or upper firebox in my case). The insulation, if I comprehended this correctly, should not be any closer than 6 inches from the top plate. So, I guess both the Armor Flex liner AND the insulation expand due to temperature rise and, I guess that is why it is recommended to secure the T and allow the top rain cap, storm collar, and clamp to float above the top plate.
What do you all think?

EDIT: You all are the greatest! Thanks.
 

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If I comprehended the directions correctly, it is recommended the T of the Olympia Heavy Flex liner "Armor Flex" should be secured and supported within the chimney (or upper firebox in my case).
No it is hung by the top plate in the chimney

The insulation, if I comprehended this correctly, should not be any closer than 6 inches from the top plate. So, I guess both the Armor Flex liner AND the insulation expand due to temperature rise and, I guess that is why it is recommended to secure the T and allow the top rain cap, storm collar, and clamp to float above the top plate.
What do you all think?
Yes it will expand but if you stretch the liner out when you install it it will just collapse on itself and not lift at the top.
 
Why give up on the hinged cap? Do they not make it in your size?
 
No it is hung by the top plate in the chimney


Yes it will expand but if you stretch the liner out when you install it it will just collapse on itself and not lift at the top.
I guess that works if the T IS supported by masonry or secured in the fire chamb
Why give up on the hinged cap? Do they not make it in your size?
Because the liner has to expand in length upward. If it does this I am afraid the cap will block the flex liner and choke my vent.
 
I guess that works if the T IS supported by masonry or secured in the fire chamb
It works just fine. If the tee moves to much I typically just use bricks under it. But the blockoff plate usually holds it in place well enough. I have never attached a tee to anything and never had an issue. And every liner manufacturer has you hang the liner from the top plate.

Because the liner has to expand in length upward. If it does this I am afraid the cap will block the flex liner and choke my vent.
It will not even rigid liners wont expand that much but a heavy flex absolutely will not if installed correctly.
 
I insulated and finished the install. I am not sure if I will install/use a decorative plate over the fireplace opening. I
should have cleaned the brickwork but that can be accomplished next season.


To Insulate or Not Insulate a Flexible Liner - That is the question! To Insulate or Not Insulate a Flexible Liner - That is the question! To Insulate or Not Insulate a Flexible Liner - That is the question!

I think I will be very happy with the performance of this US Stove 3000. I started it up on Saturday when it was 37* F outside. I opened 4 windows and 2 doors and a slider and started a mild burn. The room maintained 74*F even though I was using 2 room fans to remove the smell. The odor wasn't bad.

Edit: Let me know what you think.
 

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Thanks for the update. Time to add that big boy to your signature line.
 
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