What is a fireplace flue damper, and how do you open one?

There are many kinds of dampers, depending upon how old the house is and the choice by the masons. Many dampers have a hinge on the rear and a handle that can be pushed or lifted to lift the front and latch it open. Others have a lever designed to move with a knob or chain connected to the damper. Some chimneys have counter-balanced dampers on the top of the chimney that are opened by pulling and latching a chain. A "tilt and slide" damper not only opens with a handle, but also has a movable grating that can be "slid" open and shut using a knob cast into it. If you have a gas log fireplace and can not close your damper by the handle it is very possible that the damper has been disabled or welded open according to the 1991 building code that states that dampers in new gas log fireplaces must be disabled. The only type of damper that is allowable to use in a gas log fireplace is an inflatable damper. If you do not have a gas log fireplace and you cannot open or close your damper it is likely that it has corroded to the point of non-function. The chimney is a very acidy and corrosive environment any metal in it will rust and degrade rapidly over time. Lubricate the damper with a penetrating oil and try to loosen it by hand or call a chimney sweep to come and work on it.