Central Air Conditioner Is Cooling Intermittently.

by Joe
(Sacramento, CA)

I purchased a foreclosure home 9 months ago. The central air conditioner is a 3 ton York unit split type. House & A/C is 5 years old but has 3.5 years of use on it as house has been vacant for 1.5 years due to foreclosure.

When we first fired up the central air conditioner, the condenser fan was making a racket and barely spinning. We called our home warranty company and they had a hvac company come out. The tech replaced the fan and checked the Freon and left. It seemed to work fine.

Ever since then though, the central air conditioner blows cold only intermittently. Outside condenser coils are fairly clean and in decent shape. Air filter is clean. The condensor fan unit outside turns on and runs but mostly I don't get cold air on hot days, 95 deg+.

I've had 2 techs out since and they say the unit is working fine, but of course they were out when the unit was blowing cold. I've noticed that when it stops blowing cold, the large copper refrigerant line that connects to the outside condensor is warm and not cold.

The evaporator coils have not been checked as they are upstairs in the attic with the furnace in a pretty well sealed box. I don't feel comfortable tackling the opening of this myself to check them. Any idea what might be going on here? One tech I had over said the unit is undersized for the house.

House is 2600 sq ft. HVAC system has been split into 2 zones, upstairs and downstairs. Now I understand that the 3 ton unit probably can't cool both zones at the same time, but this unit can't even cool one zone.