/diy/ - Do It Yourself

My home ac isn't working. I just bought the house and the po had the AC compressor replaced before I bought it. Both the evap and condenser coils are clean, the filter is also clean. Airflow seems decent at the vents, it just isn't cold. The evap coil doesn't change temps at all when I switch the AC on. I checked and the compressor is running when the AC is on, it gets quite warm to the touch. Although, I expected the line from the compressor to the condenser to be warm, it didn't change temps either. I'm going to get someone to look at it, but what could cause this? Bad compressor, no refrigerant? There looked to be knobs on each line at the outside unit, I figured they were charge ports. Could there be a closed valve somewhere preventing refrigerant flow?