Diagnosed and cleared obstructed condensate line on Carrier 24ABB360A003 AC unit. Disconnected trap and flushed with CO2 cartridge. Removed algae buildup using Rectorseal Drain Solve. Installed inline P-trap and primed with water. Verified proper drainage and pitch. Confirmed 20°F delta T across evaporator coil. Recommended quarterly maintenance to prevent future clogs.