Refrigerant Recovery, Vacuum Standard and Moisture Removal Judgment Criteria

Refrigerant Recovery, Vacuum Standard and Moisture Removal Judgment Criteria

Proper recovery and vacuum are the foundation of system repair; Xiteliduo defines vacuum level and holding time for R404A circuits. Cold storage refrigeration compressor vacuum removes air, moisture and non-condensable gas after opening piping for repair work. Semi‑hermetic piston compressor target vacuum level for dehydration: 500 microns absolute pressure, hold steady for 4 hours minimum. Refrigeration compressor for food cold room moisture remaining will lead to acid generation, copper plating and expansion valve ice blockage. R404A piston refrigeration compressor recovery must use dedicated refrigerant recovery machine; mixed refrigerant is forbidden to reuse. Low temperature cold storage compressor and 2‑stage piston refrigeration compressor have larger internal volume and need longer vacuum holding time. Chinese refrigeration compressor manufacturer data shows insufficient vacuum causes 43% of post-repair ice block and acid failure. Semi‑hermetic compressor price comparison does not include vacuum and recovery service; it is a separate commissioning work. Refrigeration compressor fault troubleshooting for ice blockage first checks whether vacuum procedure was completed during previous repair. Cold chain refrigeration unit compressor skids install vacuum gauge port for technicians to monitor vacuum curve directly. Vacuum pump oil must be changed before dehydration; contaminated pump oil releases moisture and cannot reach deep vacuum. Xiteliduo emphasizes that reaching vacuum reading instantly is not enough; stable holding is the key to remove dissolved moisture. Rising vacuum pressure after isolation means moisture leakage or internal moisture desorption; continue pumping. After qualified vacuum, charge refrigerant through subcooling method instead of blind weighing.

FAQ

1. What target vacuum level for system dehydration? 500 microns absolute pressure.
2. What is the minimum vacuum holding time after reaching target? Minimum 4 hours stable holding time.
3. How many post-repair failures are caused by insufficient vacuum? 43% ice block and acid faults from poor vacuum.
4. What preparation must be done to vacuum pump before dehydration? Replace vacuum pump oil.
5. What does pressure rebound after valve isolation indicate? Residual moisture or air leakage inside the system.
6. Is instant vacuum reading qualified without holding? No, stable holding is required for moisture removal.