I have had two heat/air conditioning guys out to check my unit and they both said that my zone damper needs to be replaced. Apparently I have two for dual control. I have one with a part # that reads 645 24V 60HZ 6W 60 RPH 37944L-6 9218
The name synchron is on the part. It would be great if someone could help me find a replacement part. I have been on a mission but with no results. After two years with it not working it's about time to fix it. Plus I have a Tri level house and trying to keep it even circulated with warm/cool air is virtually impossible and very expensive with only a pellet stove for heat and a whole house fan for when it's cool out. Anyone??