How can a Chimney Balloon work in this fireplace?

How can a Chimney Balloon work in this fireplace?

Q: Jason, See below. There doesn’t seem to be enough room under my damper to use the Chimney Pillow/Balloon. There is plenty of drafts. – SZ

A: SZ, Thank you for the pictures. they are very descriptive. With this application, I would tend to recommend to put the Chimney Balloon above the damper. I see you have what appears to be sufficient room below the damper if you open it up to get the handle out of the way, but I think the best route would be to measure above the damper with a folding carpenters ruler. I have attached a diagram of your chimney if it does have a smoke chamber above the damper in the flue, If you install it high enough you may even be able to close the damper after the Chimney Balloon is installed. I am just taking a guess that this fireplace does have a smoke chamber, but even if it doesn’t I think the best install location is above the damper. See the diagram below. – Jason