Is my fireplace flue open or closed (2 dampers?) ?

How can I tell if my chimney flue is open or closed? I can tell the bottom damper is open just by looking, but there is also a wire leading all the way up the chimney. That wire can be pulled down under tension and latched, or left to hang loose. It is separate from the handle that opens the bottom damper. I have tried the match trick and the tissue trick, neither of which worked, the tissue did not go up, and the match burned equally in either position. I have also tried to see up the fireplace, but I can not see to the top and can not see light coming through either way because we live in a flight path and thus have covers 2 ft or so above the top of our chimneys to reflect noise. The reason that I ask is that I tried to have a fire last night, and everything was fine until the fire had gone down to just embers. Then we turned on the heat (central heater system) and the house filled with smoke. The fire was running for about two hours before it was down to just embers and we decided to turn on the central heat.