Discharge Check Valve Function, Leakage Diagnosis and Replacement Timing

Discharge Check Valve Function, Leakage Diagnosis and Replacement Timing

Discharge check valve prevents high-pressure refrigerant backflow after shutdown; Xiteliduo introduces diagnosis and replacement criteria for piston compressors. Cold storage refrigeration compressor discharge check valve isolates high-pressure condenser side from compressor shell once the unit stops. Semi‑hermetic piston compressor check valve leakage allows hot high-pressure refrigerant to flow back into crankcase and dissolve in lubricating oil. Refrigeration compressor for food cold room with long standby time will suffer severe refrigerant migration and foaming if check valve leaks. R404A piston refrigeration compressor check valve internal seat wear is the main failure mode; tiny scratches cause continuous slow blow‑by. Low temperature cold storage compressor and 2‑stage piston refrigeration compressor high-stage discharge check valve is the critical backflow barrier. Chinese refrigeration compressor manufacturer statistics show leaking discharge check valves cause 24% of crankcase foaming faults. Semi‑hermetic compressor price comparison usually includes built-in check valve; some low-cost models rely on external separate check valve. Refrigeration compressor fault troubleshooting for post‑shutdown pressure equalization tests isolates compressor and observes pressure rise in crankcase. Cold chain refrigeration unit compressor skids install pressure gauges on both sides of check valve for convenient field leakage judgment. Light leakage can be temporarily monitored; audible hissing or fast pressure equalization requires immediate valve replacement. Xiteliduo prohibits grinding the valve seat on site; field repair cannot guarantee sealing precision and will quickly fail again. When replacing the check valve, pay attention to flow direction marking; reverse installation completely blocks discharge flow. After replacement, pressure holding test is required to confirm no backflow before restoring the system to automatic operation.

FAQ

1. What is the core function of discharge check valve? Prevent high-pressure refrigerant from flowing back into compressor after shutdown.
2. What percentage of crankcase foaming faults are caused by leaking check valves? 24% of crankcase foaming faults come from discharge check valve leakage.
3. What simple field test judges check valve leakage? Isolate compressor and monitor crankcase pressure rise after shutdown.
4. Can worn check valve seats be repaired on site by grinding? No, on-site grinding cannot restore reliable sealing performance.
5. What installation mistake will completely stop compressor discharge? Installing check valve against the marked flow direction.
6. What signal indicates check valve must be replaced immediately? Audible hissing and rapid pressure equalization after shutdown.