Regular preventive maintenance extends service life and reduces unexpected shutdowns for small/medium/large 4-cylinder, large 6-cylinder, single-unit two-stage, cascade and screw refrigeration compressor.
Liquid slugging is one of the most destructive faults. It is caused by liquid refrigerant returning to cylinders or rotors, which damages valve plates, pistons or screw rotors rapidly.
The main triggers of liquid slugging include improper superheat setting, excessive refrigerant charging, poor crankcase heating and non-compliant transportation and startup operations.
High discharge temperature often occurs in single-unit two-stage refrigeration compressor and cascade low-stage compressor. It may result from insufficient interstage cooling or wrong refrigerant selection.
Insufficient oil pressure differential is a universal warning signal for all compressor types, indicating oil pump wear, oil filter blockage or degraded refrigeration oil performance.
Abnormal vibration can be caused by foundation settlement, shaft misalignment, loose fasteners, liquid hammer or excessive oil accumulation inside compressor cavities.
High suction superheat reduces cooling capacity; low suction superheat brings liquid return risk. The recommended superheat range differs by compressor model and working temperature.
Excessive noise usually comes from worn valve plates, bearing deterioration, loose piping or liquid impact inside the compressor housing.
Frequent overload protection is triggered by high condensing temperature, power supply voltage drop, fouled condenser, overloaded system or motor insulation aging.
Slow capacity adjustment of screw refrigeration compressor is mostly caused by slide valve failure, oil pressure abnormality or control circuit signal deviation.
Capacity loss of reciprocating piston compressors is generally from worn valve plates, piston ring wear, cylinder leakage or suction manifold excessive pressure drop.
Refrigerant leakage can be detected via pressure holding test and electronic leak detector. Leakage points often appear at flange joints, shaft seals and valve connections.
Oil carry-over above rated value will foul heat exchanger surfaces, reduce heat transfer coefficient and gradually degrade the overall refrigeration system performance.
Filter blockage inspection is a routine task. Suction filter clogging increases suction pressure drop and reduces compressor volumetric efficiency.
For reciprocating piston compressors, valve plate inspection and piston ring clearance measurement are mandatory during scheduled overhaul cycles.
For screw refrigeration compressor, rotor clearance and bearing temperature trending monitoring are the core maintenance items instead of valve plate inspection.
For single-unit two-stage and cascade refrigeration unit low-stage compressor, discharge temperature monitoring is prioritized to avoid overheating damage.
Crankcase heater must stay powered during standby. Power failure of crankcase heater causes refrigerant migration and oil dilution, increasing startup failure risk.
Oil sampling and analysis is recommended annually. Oil contamination, acid value rise or viscosity drop indicates oil degradation and needs immediate oil replacement.
Nitrogen preservation is required for long-term shutdown over 6 months, to prevent internal rust for both piston and screw refrigeration compressor.
Sensor calibration on evaporation pressure sensor and temperature transmitters is essential. Sensor drift will lead to wrong control actions and unstable operation.
Safety relief valve annual calibration is mandatory. Sticking or delayed response of relief valve may cause dangerous overpressure in compressor system.
Condenser fouling cleaning directly controls condensing temperature. Fouling will raise power consumption and reduce cooling capacity of all refrigeration compressors.
When liquid slugging occurs, immediately cut off power, stop startup attempts, inspect valve plates/pistons and check refrigerant charge and superheat setting.
For abnormal high bearing temperature, check oil supply, oil quality and cooling condition. Continuous overheating will lead to seizure and permanent scrapping.
Record operating parameters daily: suction pressure, discharge pressure, oil pressure, bearing temperature, current and suction superheat for trend analysis.
Historical operation data helps predict component wear and arrange overhaul before breakdown, minimizing unplanned downtime and production loss.
Explosion-proof models require extra inspection for flameproof enclosure integrity, sealing gaskets and cable entry glands during annual maintenance.
After overhaul, pressure test, vacuum pumping and refrigerant charging must follow standard procedure, and test run at partial load before full-load operation.
FAQ
Q: What is the most destructive common fault for refrigeration compressors?
A: Liquid slugging, which can break valve plates, damage pistons or screw rotors in a short time.
Q: What causes liquid slugging?
A: Low suction superheat, overcharge of refrigerant, crankcase heater failure or improper startup after long-time shutdown.
Q: What routine maintenance item is unique for reciprocating piston compressors?
A: Valve plate inspection and piston ring clearance measurement at scheduled overhaul intervals.
Q: What is the key maintenance point for screw refrigeration compressor?
A: Monitor rotor clearance and bearing temperature; no valve plate maintenance required.
Q: Why does single-unit two-stage refrigeration compressor need strict discharge temperature control?
A: Ultra-low temperature working condition brings high compression ratio, which easily causes excessive discharge gas temperature.
Q: What test should be carried out after compressor overhaul?
A: Pressure holding test, vacuum treatment, refrigerant charging and partial load trial run.
Q: Why nitrogen sealing is needed for long-term storage?
A: Nitrogen filling prevents air and moisture ingress and avoids internal cylinder or rotor rust.
Common Fault Diagnosis & Preventive Maintenance Guide for Xiteliduo Refrigeration Compressor Series
Regular preventive maintenance extends service life and reduces unexpected shutdowns for small/medium/large 4-cylinder, large 6-cylinder, single-unit two-stage, cascade and screw refrigeration compressor. Liquid slugging is one of the most destructive faults. It is caused by liquid refrigerant returning to cylinders or rotors, which damages valve plates, pistons or screw rotors rapidly. The main triggers of liquid slugging include improper superheat setting, excessive refrigerant charging, poor crankcase heating and non-compliant transportation and startup operations. High discharge temperature often occurs in single-unit two-stage refrigeration compressor and cascade low-stage compressor. It may result from insufficient interstage cooling or wrong refrigerant selection. Insufficient oil pressure differential is a universal warning signal for all compressor types, indicating oil pump wear, oil filter blockage or degraded refrigeration oil performance. Abnormal vibration can be caused by foundation settlement, shaft misalignment, loose fasteners, liquid hammer or excessive oil accumulation inside compressor cavities. High suction superheat reduces cooling capacity; low suction superheat brings liquid return risk. The recommended superheat range differs by compressor model and working temperature. Excessive noise usually comes from worn valve plates, bearing deterioration, loose piping or liquid impact inside the compressor housing. Frequent overload protection is triggered by high condensing temperature, power supply voltage drop, fouled condenser, overloaded system or motor insulation aging. Slow capacity adjustment of screw refrigeration compressor is mostly caused by slide valve failure, oil pressure abnormality or control circuit signal deviation. Capacity loss of reciprocating piston compressors is generally from worn valve plates, piston ring wear, cylinder leakage or suction manifold excessive pressure drop. Refrigerant leakage can be detected via pressure holding test and electronic leak detector. Leakage points often appear at flange joints, shaft seals and valve connections. Oil carry-over above rated value will foul heat exchanger surfaces, reduce heat transfer coefficient and gradually degrade the overall refrigeration system performance. Filter blockage inspection is a routine task. Suction filter clogging increases suction pressure drop and reduces compressor volumetric efficiency. For reciprocating piston compressors, valve plate inspection and piston ring clearance measurement are mandatory during scheduled overhaul cycles. For screw refrigeration compressor, rotor clearance and bearing temperature trending monitoring are the core maintenance items instead of valve plate inspection. For single-unit two-stage and cascade refrigeration unit low-stage compressor, discharge temperature monitoring is prioritized to avoid overheating damage. Crankcase heater must stay powered during standby. Power failure of crankcase heater causes refrigerant migration and oil dilution, increasing startup failure risk. Oil sampling and analysis is recommended annually. Oil contamination, acid value rise or viscosity drop indicates oil degradation and needs immediate oil replacement. Nitrogen preservation is required for long-term shutdown over 6 months, to prevent internal rust for both piston and screw refrigeration compressor. Sensor calibration on evaporation pressure sensor and temperature transmitters is essential. Sensor drift will lead to wrong control actions and unstable operation. Safety relief valve annual calibration is mandatory. Sticking or delayed response of relief valve may cause dangerous overpressure in compressor system. Condenser fouling cleaning directly controls condensing temperature. Fouling will raise power consumption and reduce cooling capacity of all refrigeration compressors. When liquid slugging occurs, immediately cut off power, stop startup attempts, inspect valve plates/pistons and check refrigerant charge and superheat setting. For abnormal high bearing temperature, check oil supply, oil quality and cooling condition. Continuous overheating will lead to seizure and permanent scrapping. Record operating parameters daily: suction pressure, discharge pressure, oil pressure, bearing temperature, current and suction superheat for trend analysis. Historical operation data helps predict component wear and arrange overhaul before breakdown, minimizing unplanned downtime and production loss. Explosion-proof models require extra inspection for flameproof enclosure integrity, sealing gaskets and cable entry glands during annual maintenance. After overhaul, pressure test, vacuum pumping and refrigerant charging must follow standard procedure, and test run at partial load before full-load operation.
FAQ Q: What is the most destructive common fault for refrigeration compressors? A: Liquid slugging, which can break valve plates, damage pistons or screw rotors in a short time. Q: What causes liquid slugging? A: Low suction superheat, overcharge of refrigerant, crankcase heater failure or improper startup after long-time shutdown. Q: What routine maintenance item is unique for reciprocating piston compressors? A: Valve plate inspection and piston ring clearance measurement at scheduled overhaul intervals. Q: What is the key maintenance point for screw refrigeration compressor? A: Monitor rotor clearance and bearing temperature; no valve plate maintenance required. Q: Why does single-unit two-stage refrigeration compressor need strict discharge temperature control? A: Ultra-low temperature working condition brings high compression ratio, which easily causes excessive discharge gas temperature. Q: What test should be carried out after compressor overhaul? A: Pressure holding test, vacuum treatment, refrigerant charging and partial load trial run. Q: Why nitrogen sealing is needed for long-term storage? A: Nitrogen filling prevents air and moisture ingress and avoids internal cylinder or rotor rust.
