Maintenance procedure for York screw compressor units

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Maintenance of compressors: In a refrigeration unit, the compressor functions like the heart of a human being; it provides the power necessary for the unit to carry out the cooling process (the equivalent of blood circulation). Therefore, the compressor plays a crucial role in the system; it is also the most expensive component, and it must always be kept in good condition. The maintenance of York industrial refrigeration screw compressors is a type of preventive maintenance aimed at maintaining the efficiency and reliability of the mechanical components related to the refrigerant at optimal levels. By comparing the costs of preventive compressor maintenance with those of repairs after the compressor is damaged, and considering only economic factors, we can see the advantages of preventive maintenance. Studies show that 55%-75% of the failures in screws and centrifugal compressors are caused by bearing problems. Under ideal conditions, a refrigeration compressor can operate for 8–14 years before it needs major repairs to replace worn-out mechanical components. Due to the harsh operating conditions of industrial refrigeration units, York recommends a major overhaul every 30,000 hours. Disassembly, inspection, and major repair of the compressor; the compressor is placed on the ground; disassembly of the machine ； Linear repair of the rotor, as well as repair of worn areas such as the casing, exhaust end cover, intake end cover, and exhaust end cover ； Repair of slide valves and sliders ； Clean each component ； Replace bearings, seals, bearing balance pistons, and damaged components ； Use special tools to reinstall the male and female rotors into the compressor chamber and adjust their positions ； Adjust the gap between the male and female rotors ； Maintenance of the drive motor: Open the fan guard of the motor and inspect as well as clean the cooling fan ； Open the front and rear covers of the motor, clean and inspect the front and rear bearings, and replace any worn bearings ； Verify and adjust the motor temperature sensor ； Check and clean the internal ventilator ； Blow out and clean the motor stator, removing dirt inside the motor ； Clean and clear the grease filling tube, and fill the motor bearings with new grease ； Inspect the moisture-proof heater; after 8 hours of moisture-proof heating, replace the air inside the motor with dry nitrogen, reinstall the front and rear end covers of the motor, and adjust the axial displacement to meet the manufacturing requirements of the motor ； The motor insulation should be tested against the load standard and recorded. During the maintenance of the refrigerant system, nitrogen is introduced into the unit until the pressure reaches 200 Psi; this helps to remove oil from the evaporator, as well as from the bottom of the storage tanks. It also removes any oil present at the lowest points in the system’s pipelines. The system is purged with nitrogen multiple times until no oil is more present in the discharged nitrogen ； Cleaning liquid level sight glass ； Replace the refrigerant dryer filter ； Inspect and adjust the level control valve and alarm level valve for the cleaning evaporator ； Clean and repair valves that are not tightly closed or those that do not rotate smoothly in the system. Maintenance of the condenser system; nitrogen leak testing for the condenser system. Check for scaling on the condenser, and determine whether to chemically clean it based on the findings. Lubricating oil system maintenance: replace the three filters and clean the oil pipelines ； Clean the oil cooler. Adjust the oil temperature control valve ； Adjust the oil level switch, and check the heater and oil temperature controller ； Check the spool control oil circuit; its operation is reliable. Replace the refrigerant oil. QUANTUM KunTeng control system maintenance – Updating QUANTUM KunTeng programs to the latest version ； Verification of digital board and power supply board ； Adjust the control programs and parameters, and conduct program testing and verification ； Check and verify various pressure, temperature, and level transmitters ； (Including pressure transmitters for intake, exhaust, oil pressure, etc., as well as sensors for exhaust, intake, oil temperature, and motor bearing stator temperature, etc.) ； Qunteng Control Center Protection Test Inspection ； Check the overload protection device of the drive motor ； Cleaning of actuators and solenoids, as well as verification of their operational reliability ； Simulated operation, control and protection verification – manual testing of all actuators and solenoids showed normal operation and correct protection responses. System restoration for compressors, motors, etc. and seal inspection: Install the compressor back on its unit base, connect the motor, and restore the system pipelines and electrical connections ； Nitrogen is filled into the unit to a pressure of 200 Psi; the pressure is held to check for leaks, a thorough inspection for leaks is conducted, and any defects are repaired ； Maintain pressure for 12 hours to check for leaks in the safety valve, etc. During maintenance, custom detailed safety measures and emergency response plans are established