Upon arrival unit was on but the thermostat was satisfied. Turned thermostat down and both indoor and outdoor units turned on. Checked the evap coil and the air filter and both were clean. Checked refrigerant levels and found the liquid pressure was very high. Found the condenser coil was very dirty. When the condenser coil is dirty it raises the refrigerant temp and pressure, also making it harder for the unit to cool properly. After getting customer authorization we chemically cleaned the condenser coil. After cleaning the coil we found the unit was slightly low on refrigerant. The manufacturer calls for a subcooling of 7* at 85* outside but the unit was only at 3* subcooling. After getting customer authorization we added 7 oz R410A to the system bringing the subcooling up to 9. Unit is working properly. Had 10* temp split when arriving and 17* split when leaving.