Have Carrier 9200 Weathermaker. Noticed today during blizzard that insulated flex hose from outside that conects into cold air return has snow buildup and is dripping water. Called service man who said to just disconnect hose and cover with plastic - it was fresh air hose and don't need it. So I put duct tape over 5 inch hole in cold air return duct and covered flex hose with plastic bag. Went outside and covered outside opening as well. Noticed plastic bag over flex hose in basement seemed to puff out and retract much like a "breathing motion". Is this flex hose connected to a motor somewhere? Should I have disconnected it? This is NOT the PVC pipes that are the air intakes and vent. Serviceman said he doesn't know why anyone would want to heat cold outside air - should just be heating inside air. PS - we are in cold area - blizzard today and 20 below zero.

The hose as you call it was placed there to supply air for these possibilitys. Make up air/fresh air, or combustion air. It was put there for a reason. Possible reasons are that it was called for in the manufactures instructions OR the local building code required it. The movement in and out of the plastic cover on the hose end is caused by the differential in pressure probably caused by the furnace blower when it comes on and off. You will have to find out the real reason for it being installed before I would just leave it disconnected.