Customer has 3 y/o Carrier heat pump system that operates for basement level. System was not working properly due to faulty thermostat. Installed new Ecobee thermostat. Tested heating, cooling, and auxiliary heating. Replaced 16x20x1 filter. No pan water protection present. Recommend UV BlueTube to target and prevent biological growth. Pressure levels were low indicating loss of refrigerant. Unable to properly diagnose leak due to customer time restriction. Informed customer of findings.