Used screw compressor

Buyers must prioritize the Actual Free Air Delivery (FAD) and Working Pressure (Bar/PSI) to ensure the unit meets operational needs. It is critical to check the Total Running Hours versus Loading Hours; a high ratio of loading hours indicates heavy usage. Additionally, verify the Motor Insulation Class (typically Class F) and the Cooling Method (Air-cooled vs. Water-cooled) to ensure compatibility with your facility's ventilation and utility setup.

The Air End (Screw Host) is the most expensive component. Request a Vibration Analysis Report or a video of the machine running to listen for abnormal metallic noise. Check for Oil Leaks around the shaft seal. If the unit has exceeded 20,000 to 30,000 running hours, inquire if the Bearings have been replaced, as this is a standard overhaul interval for brands like Atlas Copco, Ingersoll Rand, or Sullair.

Ensure the motor's Voltage (V) and Frequency (Hz) match your local grid (e.g., 380V/50Hz vs. 460V/60Hz) to avoid costly transformer requirements. The unit should ideally carry a CE Mark for European markets or ASME Certification for the pressure vessel (oil-gas tank) if shipping to North America. Always request the Original Pressure Vessel Certificate to ensure the tank is safe for pressurized operation.

Before commissioning, perform a Full Service (PM Kit) including replacement of the Oil Filter, Air Filter, and Oil-Air Separator. Check the condition of the Minimum Pressure Valve and Thermostatic Valve. It is highly recommended to source from suppliers on Made-in-China.com who provide a Refurbishment Report detailing which wear parts were replaced prior to sale.

Always request a Live Video Inspection showing the compressor reaching its Target Pressure and Unloading. Use Third-Party Inspection Services (like SGS or Intertek) to verify the machine's condition at the supplier's warehouse before final payment. Ensure the transaction is protected by Secure Payment Terms offered by reputable platforms like Made-in-China.com.

Compressors contain residual oil which may be classified as Hazardous Material by shipping lines. Ensure the supplier Drains all Lubricating Oil before packing and secures the Internal Vibration Isolators with shipping bolts to prevent alignment damage during transit. The unit must be packed in a Fumigated Wooden Crate to comply with international maritime regulations.

Clarify the definition of 'Refurbished'. A true refurbishment should include New Bearings, New Gaskets, and a Cleaned Heat Exchanger. Negotiate for a 6-month to 1-year Warranty on the Air End, even for used equipment. If the price is significantly lower than market average, verify if the Inverter (VSD) is original or a cheap aftermarket replacement, as this affects energy efficiency.

Many countries require a Pre-Shipment Inspection Certificate (PSIC) for used machinery to ensure it is not 'electronic waste.' You will need the Commercial Invoice, Packing List, and Bill of Lading. Ensure the HS Code (typically 841480) is correctly declared and check if your country imposes specific Environmental or Energy Efficiency Taxes on older industrial models.