Core Precautions for Using R404A in Piston Refrigeration Compressors

Core Precautions for Using R404A in Piston Refrigeration Compressors

1. Oil Matching: Must use synthetic ester oil (POE); mineral oil is incompatible with R404A and will cause lubrication failure.

2. Material Compatibility: Ensure system components (valves, gaskets, hoses) are resistant to R404A. Avoid ordinary rubber; use EPDM or Viton seals to prevent swelling and leakage.

3. Pressure Control: R404A has a higher saturation pressure than traditional refrigerants (e.g., R22). Strictly monitor the discharge pressure to prevent compressor overload or cylinder explosion.

4. Vacuum Requirements: Achieve a deep vacuum (≤50Pa) before charging. Residual air or moisture will react with R404A to generate acidic substances, corroding the compressor and blocking the system.

5. Charging Method: Charge in liquid state (never gaseous) to avoid refrigerant composition separation (R404A is a mixed refrigerant) and ensure system performance.

6. Leak Detection: Use nitrogen pressure test + vacuum holding for leak detection. Soap water can also be used for local checks, but avoid using refrigerants directly for leak testing to prevent waste and environmental pollution.

7. Safety Protection: Wear gloves and goggles during operation. R404A is low-toxic and can cause frostbite if it comes into direct contact with the skin; ensure good ventilation in the operating area.