Hello, I just helped my friends put their same model back in their fireplace. They have oil heat and really need to cut the fuel bills down. This unit heats their whole upstairs! The damper slides in and out over the back of the unit, we actually forgot to put it in. So therefore the flue on the back of the insert is wide open. They adjust the draft from the front with the air inlet knobs. I think the rod could be used to further control the draft from the backside, if you want the doors open to view the fire. They also have a screen that fits over the open doors! You could have one made. This is an awesome unit, also has a blower fan that really puts out the heat!