I performed a diagnostic and upon arrival customer stated condenser fan motor would not start unless you manually pushed it to start. Sent call for cooling and found contactor pulled in and unit humming. Tested capacitor and found dead so I replaced and unit started. Had a delta of 14 degrees in a downflow application. Checked refrigerant level, it was slightly low with a sub-cool of 3.4 degrees. Added 1 pound of 410-A to acquire desired sub-cool of 10 degrees. System operational at time of departure.