As the heating season progresses my primary air control gets harder and harder to pull and push. So figuring it was just dirty I pulled it out and cleaned it off even though it looked great. On the bottom side of the control you can see where is rubs/drags. So I now have been spraying greaseless lubricant on it and reinserting it into the stove. So far it works great for about 3 weeks then I have to do it again. Anyone else have this issue?