Arrived to diagnose 6 RTUs, all 6 units are from 2016, R410A, and Heat Pumps RTU #1 : System operates as designed RTU #2 : Grounded compressor RTU #3 : Outdoor TXV ( utilized in heating ) has failed. Sensing bulb is no longer attached to the TXV and equalization line has a leak in it. Video attached RTU #4 : Phase Control Monitor has failed RTU #5 : System is empty on refrigerant. Conducted an electronic leak search, found low 1-7 ppm of refrigerant at evaporator. RTU #6 : Contactor on indoor fan had failed. 0 ohms across low voltage side of coil. System operates as designed