Performed 1 system cooling maintenance. Added pvc union and flushed drain line. Tested all electrical components for normal operation. Black mold growing inside supply plenum. Recommend installing u/v lighting system to kill mold. Air handler has pan switch but no inline secondary. Recommend installing e-z flow inline switch. System has no form of power protection. Recommend installing surge protector to keep components safe from electrical damage. Recommend installing compressor saver on outdoor unit to keep compressor amp drawl down, help with noise and brownouts during startup. System operating normal at this time.