In Union, NJ, I repaired a Lennox XC21 HVAC system that was not cooling properly due to a clogged condenser coil. After thoroughly cleaning the coil, I checked the refrigerant levels and found them low. I recharged the system with R-454B refrigerant, which is more environmentally friendly. I also tested the compressor and expansion valve to ensure they were operating correctly. After the repair, the system is now cooling the home efficiently, providing optimal performance and energy savings.