Help! Chimney to narrow for 6"pipe and insulation

[kevinmerchant]

I know i have read about this problem somewhere, but ignored it because I thought my chimney had a larger flue.
The inside is 6.5 x 10.5. Stove has 6" pipe. I also wanted to insulate.
Any recommendations.

 

[begreen]

Are there any offsets in the chimney flue or is it straight up and down? If so, ovalized insulated liner should work.

 

[kevinmerchant]

Flex pipe I assume. What size oval. Any recommendations on where to buy. Would a 5.5 round also work. Can I connect the flex pipe directly to stove. Its a Vermont Castings Dutchwest, 1/2 inside fireplace. Also, I burned 2 seasons without liner and now have some glazing the sweep didn't completely get rid of this spring. Does that need to be removed before liner install.

I will be putting my other fireplace to work this year with a Avalon 745 insert. This one has a larger flue so I was thinking of going with double wall rigid insulated liner. Found some at Lowes for only $67 for 3ft section. Name is Super Vent. Has anyone heard of this, is it any good. I would need flex to go through fireplace damper. How do you connect 6" flex to double wall rigid.

 

[kevinmerchant]

Sorry I didn't answer your question. Yes, its straight for the most part except a slight angle as it goes through wall into fireplace

 

[begreen]

Sorry I didn't answer your question. Yes, its straight for the most part except a slight angle as it goes through wall into fireplace

If straight, you may be able to install rigid until you get to the damper. Look at Simpson DuraLiner. It comes ovalized - 4.75 x 7.75", rigid and flex:
http://www.dynamitebuys.com/store/cart.php?m=product_list&c=66
catalog with all the fittings:
http://www.dynamitebuys.com/store/pdf/SimpsonDuraVent-DuraLiner.pdf

 

[stejus]

I know i have read about this problem somewhere, but ignored it because I thought my chimney had a larger flue.
The inside is 6.5 x 10.5. Stove has 6" pipe. I also wanted to insulate.
Any recommendations.

You can pour this mix down your flue after the stove liner has been installed. You just need to block off the flue at the bottom, mix material with water and pour into flue from the top.

 

[CarbonNeutral]

My thread on the same issue


I am going duraliner - once I can find someone to install it......

Here's another thread where we get into how the oval shape should not affect flow compared to round:

https://www.hearth.com/talk/threads/39883/

 

[Metal]

As you ovalize a pipe you get less area so you will have to go up in size (perfectly round maximizes area of a pipe). A 5.5" only works if it is okayed by the manufacturer of the stove. If it is you can get a 6"-5.5" adapter and be on your way.

 

[CarbonNeutral]

As you ovalize a pipe you get less area so you will have to go up in size (perfectly round maximizes area of a pipe). A 5.5" only works if it is okayed by the manufacturer of the stove. If it is you can get a 6"-5.5" adapter and be on your way.

For the amount of ovalizing, I'm not sure this is really true - you get narrower, but you also increase the other dimension. Unless you're doing something crazy I would bet the area is pretty similar. That said I would be concerned if the stove needs a 6" and you're ovalizing a 5.5". Also, I'd rather do an ovalized 6" than a 5.5" round.