Q: Jason, My fireplace has a small flue that is 7.5 inches in diameter. The type of fireplace damper I have is a small swivel type of damper. The damper is a round plate with a metal rod handle that goes through the middle of the round plate. See photo taken from inside the fireplace firebox looking up at the damper. Can I use a 9×9 Chimney Balloon on this chimney flue? – DC
A: Dear DC, Thank you for sending the photo of the swivel fireplace damper in your fireplace. A picture is worth a thousand words when it comes to describing fireplace dampers.
I would guess you have a gas log fireplace considering I think I see a clip on your damper holding it open. Often these clips are put on dampers according to building codes that dictate that a fireplace with a gas log fireplace unit must have the damper disabled or clipped open if they have a vented gas log. This code was written so that a family will not be asphyxiated with Carbon Monoxide if someone turns on the gas log without opening the damper first. The unfortunate thing is having your damper open all the time lets in a lot of cold air and lets out a lot of expensive home heat.
A Chimney Balloon can be used in this flue and I would recommend a 9×9 Chimney Balloon with an HEK handle extender. When you insert the 9×9 make sure you DO NOT pre-inflate it at all. Simply attach the handle extender to the handle before installation, so that you will have plenty of reach to get the Chimney Balloon past the swivel damper and into a clear spot in the flue. Then slide the Chimney Balloon past the open damper and inflate it in place once you have it in the flue.
Since the 9×9 is slightly over-sized for this 7.5″ flue. If you start overinflating the Chimney Balloon you will notice that it will tend to want to tilt or tip sideways in the flue. If this starts to happen, simply remove a little air from the Chimney Balloon and coax it back down into horizontal position by pulling lightly on the handle valve. Let me know if you have any other questions. – Jason