Fireplace #1: Butterfly Damper 3 Feet above the Firebox

These high-up butterfly center pivot dampers are usually in prefabricated zero clearance fireplaces made by Heatelator.  Here are the characteristics:

  • The damper handle that opens the circular center pivot damper is usually on the outside lintel¬†face of the fireplace.
  • You will notice that there are horizontal slats cut in the sheet metal just below the closed damper.

Those vent slats below the round damper gives you a pretty good place to tuck in a square Flueblocker. Measure the area below the damper (Image 1-3), and buy a Flueblocker that is a little larger than that area. Most of the time it requires a 12″x12″ Flueblocker, or a 16″x16″ trimmed down to fit. Just make sure you keep that pressure fit by having the pad be larger than the hole.


Because this install location is up out of reach, you will likely need to buy some extra 6″ Handle Extenders for your Flueblocker.