Confused about wheather to fully insulate SS chimney liner for insert

[CBL]

I did a search but i would like some clarity.... I am preparing to get ready to reline my chimney for my p35i insert. I'm running 25' of 4" and I recently ordered an SS flex king pro liner.

The harman manual makes no mention of suggesting to insulate the whole liner, only below the block off plate is where they mention to do so . But the flex king pro manual mentions its suggested to do so (doesn't say required). I hear some people do it and some people don't. I'm also reading just packing in some roxul at underneath the bottom of the top plate and at the bottom of the block off plate is adequate to create dead air space.

My chimney is exposed on side of the house and is newer fully flue tiled and in good shape.

I do plan on drawing outside air from the chimney flue so there will be some small vents at the top plate.

Maybe I'm overthinking this but just want to be 100% sure I don't regret not insulating it first before i jam it down there.

Opinions? Thoughts?

 

[john193]

No need to insulate the liner when going through a masonry chimney. The point of insulating the plate and cap is really for efficiency sake. You have the right idea already. Skip the liner and insulate the cap and damper.

 

[DexterDay]

Sounds about right. Insulating a pellet liner, not entirely necessary. Your on the right track.

Although I would seal both ends and insulate. Then run an OAK to the top..


Yes.... OAK. You said you plan on doing it. So do it.

 

[CBL]

Ok good to know, makes me feel better about it.

a pellet liner, not entirely necessary. Your on the right track. Although I would seal both ends and insulate. Then run an OAK to the top..

OK next question, The manual is specific on this point and suggests not to run the OAK all the way to the top, but terminating it mid-way into the flue and then having a couple of small vent holes at the top plate so outside air can draw in. The requirement is to keep it at least 5' away from the top. On a cold day, if its drawing in air from outside for combustion wouldn't that cool the inside of the flue and defeat the purpose of insulating under the top plate?