Performed A/C tune-up on a Carrier heat pump system. Checked the electrical, mechanical and performance systems of the unit. Cleared, cleaned, flushed and treated the drain line and cleaned the exterior of the air handler. Secured the compressor wiring and washed the outdoor coil. I did find the system was slightly low on refrigerant. I spoke with Mr. Brown and he chose to add refrigerant at this time. I added 1 lbs 6oz of refrigerant. I also performed a leak search but was unable to find a leak. No other issues were found. The system is operational at this time.