On Jan 17, 5:21Â*pm, terry wrote:
On Jan 17, 7:26Â*pm, " wrote:

On Jan 17, 9:26�am, "S. Barker" wrote:

It is possible to create too much draft. �But going up just one pipe size
won' t do that. �I have a fireplace insert with an 8 inch outlet and my
chimney is 12 inches square. �Sometimes when i open the stove doors, �it
just goes ape! �Also the smaller pipe will stay cleaner due to it's running
hotter.

the effective size of a square or rectangular chimney is the largest
circle that can fit inside, so your 12 inch square isnt as oversized
as you might bellieve

You mean????
a) 12 by 12 = 144 sq. inches.
b) Pi x (r squared) = 3.142 x (6 x 6) = 113 sq. inches.
If and when you install a metal flue liner within an existing masonry
chimney?
c) Eight inch Â*pipe. Â*Pi x (4 x 4) = 50 sq. inches.
smaller pipe might be better in some circumstances and stay hotter for
less soot deposit?

airflow near corners is poor, thats why i said what i did