Chimney Liner Question

[Heat4Life]

Good Morning, I am new to the forum and solid fuel used for heating. I just purchased a PSG Caddy wood furnace. We are preparing to line our chimney with a 316ti flex liner. Our chimney currently has a clay liner inside brick that extends about 30ft from the furnace to the top. With the high efficiency furnace is it necessary to insulate the new liner?
By the way this site is very helpful and informative and I am glad to be apart of it!

 

[bholler]

Yes it probably needs to be insulated it will work better and be safer. And infact unless you have the required clearance from the outside of the masonry (1" for an exterior chimney and 2" for interior) to combustibles it is required by code.

 

[Stoneduster]

A 304 alloy would be all that you need for a solid fuel appliance. 316 generally goes into flues that service oil appliances because the accumulations are much more corrosive. A 6" round, 30' long, heavy wall kit in 316 is roughly $960 from my chimney supply company, versus $569 in 304. And you should always insulate when using solid fuel appliances. It is absolutely worth it, you will end up with a coffee cup's worth of fly ash after a season.

 

[bholler]

I could not agree more with stone dusters post and i would also recommend heavy wall that is all that we use for wood stoves and we insulate every liner we put in regardless of the appliance clearances or location of the chimney

 

[philupthegastank]

what have you used to insulate? a product like this? (broken link removed to http://www.duravent.com/docs/product/TherMix_Bulletin_2011_web.pdf) and would you suggest a rigid over a flex liner? I have a straight masonry chimney in the middle of the house with no liner. (not currently living there)

 

[Stoneduster]

I have used a similar product with rigid liner systems, the only potential problem with Thermix insulating a flex liner is that the liner probably won't land in the center of the flue during the pour, resulting in inconsistent amounts of insulation around the liner. I generally use a ceramic wool blanket. (broken link removed to http://newenglandchimneysupply.com/section10.shtml#liner-wrap-insulation-kit)

 

[bholler]

We use both types of insulation it just depends on the situation but you will find that many rigid liner systems are not approved for use with pour in insulation. We almost never use rigid any more really the only time we will consider it is for coal otherwise we use heavy wall flex liner for wood. And light wall for oil or gass