I am a skilled professional that works for a Sheldon's Heating & Air Conditioning company. I was called to a customer's home to check on a unit that was not cooling. Upon arrival, I checked the indoor and outdoor units. I found that the filter was dirty and needed to be changed. I also checked the ductwork for any damage and found none. I checked the drain line and found it to be clear. I checked the temperature and found that the unit was blowing a 20-degree split. I then went to the outdoor unit and checked the electrical components. Everything was within range. I rinsed the outdoor coil with water and removed all the dirt. The unit is now working properly.