Q: Jason, I have a Heatilator Mark 123 fireplace that has a fireplace damper that is actuated by a pull chain. It is very cold in the winter and I can feel a draft come down and out of the fireplace. I see that you recommend putting the Chimney Balloon in above the damper, but the damper is about 3′ up in this application. Also, just below the damper, the walls of the flue in this area are perforated by a series of linear vent slots in an area that is about 10″ vertically. The firebox of this fireplace is trapezoid in shape (25″ length in back, 32″ length in front and 16″ from front to back) and lined with firebrick. There is a slight 1″ ledge just above the firebrick and then the metal flue immediately starts gathering upwards like an upside down funnel. My question is…where do I install the Chimney Balloon? Above the damper, below the damper, or just above the firebricks and the firebox? – FF

A: Hi FF, This Heatilator fireplace is a very common fireplace (especially in condos) and we are often asked about this particular application. We have found that it is possible to put a Chimney Balloon in any of these locations you mentioned, but installing a Chimney Balloon just above the firebox on the 1″ ledge is by far the easiest install point.

How to do the Low Install on the 1″ Ledge:
Take a 36×15 Chimney Balloon plug and unroll it out of the package so it is flat. Hold the Chimney Balloon by the valve handle in one hand and connect the inflation tube to the Chimney Balloon, and then connect the other end of that inflation tube to a Chimney Balloon pump. You will find it is easier to do this install with a pump since you will need both hands to get the Chimney Balloon into place as it inflates.

Tuck the Chimney Balloon material around all 4 edges of the ledge that is just above firebox while you hold the Chimney Balloon in place with your other hand. When you have the balloon roughly in place turn on the pump and it will start to inflate. As it inflates continue to hold the balloon in place with one hand by holding the handle valve. At the same time use your other hand to continuously work the edges of the balloon material and make sure it is staying above the ledge as you inflate. As the balloon gets tighter you will feel it start to grab and lodge itself in place.

* Note* Do not adjust the position of the Chimney Balloon while it is fully inflated. If you need to adjust its position leave the valve open and let some air escape first so the Chimney Balloon will be more pliable.

The Chimney Balloon may be slightly visible from the hearth since the install is very low, but the clear Chimney Balloon is hardly noticeable especially if you close the spark screen.

How to do the High Install just above the damper:
For a bit more of a challenge you can install a 9×9 Chimney Balloon in the flue just above the damper but you will need an Extra long 26″ HEK Extender for the handle (the 26″ is a special sized HEK extender that is not listed on the website yet, so you will need to call in your order). Attach the extra long HEK extender to the 9×9 Chimney balloon and unfold the flattened Chimney Balloon, so it is perpendicular to the long handle. Put the Chimney Balloon through the open damper so the handle sticks down through the open damper door and then inflate the Chimney Balloon into place. It is a bit tricky to get the Chimney Balloon to inflate flat in an area that is so high, so you may want to have your folding carpenters ruler handy to prod it into place if necessary. This higher install also seals well, it is just a little harder to do.

– Jason