How to open fireplace flue. See a diagram of the parts of a chimney here when the damper is closed it slows the loss of heat that would otherwise go up the chimney. A throat damper is a metal door located above the firebox but below the flue pipe. The flue is essentially a channel inside the chimney the smoke is funneled through and its controlled by the damper a pair of small steel doors.
You need to open your fireplace flue to create an efficient fire and reduce the amount of smoke and carbon dioxide in the room. Adjusting the damper helps you burn a fire safely and efficiently. The easiest way to tell if the fireplace flue is open is by placing a hand into a cooled fireplace and feeling for cold air.
Adjusting the damper allows you to burn a fire efficiently and safely.