In order to work properly, the AC unit has to have proper air flow.
Air has to flow into the machine and out of the machine.
There are air vents located all over the house to ensure proper airflow. When one of these air vents is blocked, problems can occur. One of the worst issues happens when the return vent is blocked. I serviced an AC unit last weekend and that was the issue. The customer moved to the house on the previous weekend. The movers placed all of the boxes inside of the house on the day before the customer arrived. Several boxes were blocking the return vent and the AC unit did not have proper air flow. Two days after the customer started unpacking, the AC unit broke down. She called the AC repair company where I work and I was assigned to the repair call. As soon as I entered the house, I noticed all of the boxes laying around. I started searching for the return vents and I only found one. I knew the large house had more than one return vent, so I started looking behind boxes. Sure enough, two large boxes were blocking the entire return vent. I moved the boxes, cleaned the system and serviced the machine. I don’t think the customer will have any other problems with the unit for a while. The equipment looked fairly new and I didn’t see any problems other than the blocked air vent in the living room area. To be honest, the house was pretty nice too. It had a beautiful wooden swing on the front porch and shutters on the windows.