Performed diagnostic on 2017 Lennox builder grade heat pump system. This is a zone system. This unit is not sufficient for a zone set up. It was a bad design from the beginning. This unit has frozen and water has gotten the ductwork ductwork has collapsed and caved in the ceiling in the bedroom upstairs. The reason the system froze up is because the coil is no longer metering refrigerant properly. Tested system and coil by removing the bulb and testing outside the coil. There is no change. I added a pound of refrigerant. There was also no change.The system needs a new coil, all new refrigerant, and a section of 10 or 12 inch ductwork replaced at minimum recommend adding more flood protection if you were gonna even consider repair. The only flood protection in place is the very very minimum. There is a drain pan safety switch that apparently did not do its job. Recommend adding a wet switch and an SS one in line drain safety. I will quote prices these repairs, but they are going to be v