A chimney with two or more concentric metal pipes (an air-cooled flue) will need a special type of chimney cap that insures the
cooling air properly flows from pipe to pipe. Insert such chimney caps into the inner most pipe. The collar should cover the outer most pipe.
To install an inside mount chimney cap into a metal flue, just push the cap firmly into your flue.
Bottom View of Compression Fit Chimney Cap
To install a compression fit chimney cap, squeeze the overlapping parts on the bottom of the chimeny cap (as shown at left) and insert them into your
flue. When you let go, the overlapping parts will spring tight open against the inside of your flue, securely holding the chimney cap in the flue.
To install a compression fit chimney cap squeeze the bottom before inserting it into your flue.
If you don't yet have your chimney cap for your metal flue, take the
FireplaceMall Chimney Cap EASY MEASURE Guide up on the roof with you to help you correctly measure for the type of chimney cap you need.