Finishing up a repair on an air conditioning unit that was failing to start. Upon inspection, I identified a burnt-out compressor relay. I replaced the faulty relay with a new Packard PR340 relay. I also tested the system's refrigerant levels using a Testo 550s digital manifold gauge and found them to be low, so I added R-410A refrigerant to the appropriate levels. Additionally, I cleaned the evaporator coils with Nu-Calgon Evap Foam to improve heat exchange efficiency. The unit is now operating correctly and providing optimal cooling.