We have a Marco Fireplace(not one that is recalled) model number 792794. We have always had trouble with the venting of the fireplace either when using gas logs or wood logs. We have just discovered on the right side where the screen draws back to, a rod about 3-4 inches that seems to pull up or down and sounds like a flue opening. I can't find any drawing on this fireplace and I'm wondering if this might be our answer? Any thoughts

That could be it, if you feel cold air coming in when you open or pull or push the rod, ide say your onto it. Good Luck P.S.leave it open for the fir and close it afterwards to conserve energy.