Have an old throat damper with the knob that you slide by hand on the inside of the fireplace. The blades that slide with the knob are broken and no longer move in unison. So every time we use it we have to individually move the blades out of the way, and then back again after it cools down. How do I Replace this? Can I replace just the blades? Or the whole damper? If so how do I measure it?


Rich