BPatrick wrote:piece of loose insulation (without the paper of course) and tightly stuff it just inside the cleanout door. He said don't go all the way to the back, just inside the door then close it. Walla problem solved. Apparently the door leaks a small amount of air and will interfere with the chimney draft especially on low draft conditions.
I don't understand, what are you referring to as clean out door. I have a Crawford 40 base heater. I don't know where I would be able to put that?
He's talking about the one in the chimney, not the stove.
Most masonry chimneys are built with a cast iron door and frame near the base to allow cleaning out anything that can fall down the chimney, such as ash, wind-blown leaves, critters, etc..
The doors don't seal well, and as he said, they can cause cool air leaks into the chimney cooling off the flue gases and slowing draft.