Jason – I converted my masonry fireplace with natural gas and installed an unvented gas log set. Can I install a Chimney Balloon above the damper, keeping the damper closed and ignite my gas logs without incurring any damage to the Chimney Balloon? The gas log set is rated at 39K but. Thanks, CB
Dear CB, If the temperature in the flue gets to about 200 degrees Fahrenheit it will trigger the release mechanism in the Chimney Balloon. Essentially the Chimney Balloon membrane melts and shrinks at the same time and the Chimney Balloon falls out of the Chimney. I’m betting that you will get heat conducting through your damper that will exceed 170 degrees within minutes with this vent free gas log turned on. Unfortunately, the metal from the damper will conduct the heat right through.
On the other hand, it will benefit you to use a Chimney Balloon above the damper when you are not using the fireplace. This is how it is normally used and it will keep your nice warm inside air inside where it belongs and not be floating up past a leaky damper.