1, the four-way valve is leaking (broken), which may be repaired (repaired) through the efforts of the maintenance worker; fixed
If it cannot be restored, only the four-way valve can be replaced.
2. The refrigeration system (copper tube part) has "leakage" of fluorine, which makes the refrigeration system "fluorine-free".
3. In the refrigeration system, there is a "blocking" phenomenon. You need to disconnect the copper tube of the refrigeration system and experiment the "suction and exhaust" of the compressor respectively before you can "confirm".
If the compressor is "dead", make an accurate judgment: you need to disconnect the high-pressure exhaust pipe and the low-pressure suction pipe on the compressor, and then run the compressor. In this case, if there is no "suction and exhaust". You need to replace the compressor.