Diagnosed malfunctioning 4-ton Rheem heat pump. Performed electrical testing, revealing failed dual capacitor. Replaced with 45/5 μF 440V run capacitor. Cleaned condenser coils using foaming cleaner to improve heat rejection. Checked refrigerant charge, finding slight undercharge. Added 0.8 lbs of R-410A to achieve proper subcooling. Calibrated thermostat and verified correct defrost cycle operation. Final performance test showed 13° delta T across evaporator, indicating restored cooling efficiency.