Insulating the liner for quad 4300

[agz124]

I will be installing my liner this weekend and I asked my 2 local stove shops, from one of which I bought the liner, about insulating and they gave me 2 very different answers.

One said: Just pull the paper off fiberglass insulation and stuff it around the top of the liner (in between the liner and old terra cotta), just a few inches will do the trick to hold the heat in there and keep the liner warm.

other guy: Never put fiberglass insulation around the liner, don't insulate at all unless you have draft problems and with a highly effecient stove (quad4300) you might. In that case, start at the bottom by using double wall stove pipe and see if that corrects the issue.


Thoughts?

 

[begreen]

Hmmm. Both sub-par suggestions. Do you have room in the flue for insulation? What are the flue dimensions? Is this an interior or exterior chimney. If interior, insulation may not be needed. You'll still need a block off plate, but that is a separate issue entirely.

PS: Can you add your Lancaster, PA locale to your avatar info (control panel - location)?

 

[agz124]

Most of the chimney is interior. It is a brick chimney that is exposed on 3 sides (meaning if you are in our living room you can see 3 sides of the chimney the 4th side is exposed to outside and is even with an exterior wall). This is a free standing application, I am just replacing an old stove with a new one but adding a liner. The old flue is rectangular 7x11 inside dim. The flue is jogged about 8 inches from the crock to the top of chimney. It jogs side-to-side, meaning the 7" is probably more like 6.5" where the jogging is happening. I bought a 6" flex liner and I am prepared to ovalize it if needed, but I plan on trying it first. I know blanket insulation is not an option because of clearance.

 

[BrotherBart]

I wouldn't use the fiberglass insulation bottom or top because of low melting temp (around 1,200 degrees) and a tendency to sag. I used rockwool mineral wool insulation packed into the top three or four feet of both of my exterior masonry chimneys and on the one that comes into the fire place I put a couple of feet of it on top of the blocking plate. Works great.

I figure with mineral wool if things ever get up to the 2,300 degree melting temp I will be over at the neighbors house watching the fire anyway.

 

[agz124]

Where would I find rockwool?

 

[TMonter]

Any boiler supply house in the area should carry it. Just ask them for a high temperature ceramic fiber or block insulation.

 

[stoveguy13]

With the amount of space and jogs you have in the chimney it does not sound like it will be very easy to insulate with typical insulation methods. you do not really want to ovalize the 6 inch liner as it is like stepping on a garden hose it will reduce the flow. the best solution would be to find some one in your area who knows about theramix it is a poor in insulation.

 

[agz124]

It turns out that I did not have to ovalize the pipe at all. I bought a 25' (only needed 19') roll and just ovalized the first 3 feet and then after I got the liner in I cut off the ovalized part. It worked perfect. What a relief! My stove guy said to use rockwool insulation and stuff it around the top of the liner (in between the liner and the old flue) and then attach the top plate and cap. I am also doing the same thing at the stove where the liner comes out the side of the old flue, through 3 courses of brick and about 5 inches of mortar! Drilling that hole was no fun.