Piston compressors may encounter various faults during use. Here are some common faults and their possible causes:
1. The compressor cannot start and operate normally
Power failure: such as power outage, low voltage, and phase loss.
Electrical circuit faults: such as blown fuses, loose contactor wiring, etc.
Motor malfunction: There are problems with the motor itself, such as damaged windings, damaged bearings, etc.
High crankcase pressure: caused by leakage of exhaust valve plates, malfunction of energy regulation mechanism, and other reasons.
Energy at high load position: The compressor is in a high load position and cannot be started.
Temperature controller malfunction: The temperature controller is out of control or malfunctioning, causing the compressor to fail to start.
Pressure relay failure: The set value of the pressure relay is too low, the alarm is not reset, or it is malfunctioning.
Low oil pressure: unable to establish normal oil pressure, causing the compressor to fail to start.
Cooling water or refrigerant water cut-off: The water flow relay alarms or malfunctions, causing the compressor to fail to start.
2. Sudden shutdown of compressor during normal operation
Power outage: Sudden power outage causes the compressor to shut down.
Alarm shutdown: The operating parameters of the unit reach the set alarm values, such as main motor overload protection shutdown, exhaust pressure high alarm shutdown, low oil pressure difference protection shutdown, cooling water or refrigerant water cut-off alarm shutdown, etc.
3. Low oil pressure
Blockage or oil leakage in the oil pump pipeline: causing the oil pump to malfunction and the oil pressure to decrease.
Malfunction of oil pressure regulating valve: Improper or malfunctioning regulation leads to unstable oil pressure.
Oil shortage: Insufficient lubricating oil in the crankcase leads to a decrease in oil pressure.
Crankcase fluid inlet: the oil pump sucks oil with foam, causing the oil pressure to drop.
Oil pump wear: The oil pump components are severely worn with excessive clearance, resulting in a decrease in oil pressure.
Wear of connecting rod bearing and main bearing: Severe wear leads to a decrease in oil pressure.
Oil pressure gauge malfunction: The oil pressure gauge valve is not open or the gauge is malfunctioning, unable to accurately display the oil pressure.
4. Foam in crankcase
A large amount of liquid is injected into the crankcase: when the pressure drops, the ammonia liquid will evaporate and cause foam.
Excessive oil filling in the crankcase: the big end of the connecting rod stirs the lubricating oil, causing foam.
5. Oil temperature too high
Cooling water system issues: The oil cooler in the crankcase is not supplied with water, the water temperature is high, or the water volume is insufficient.
Assembly issues with bearing shells and bearings: The assembly clearance is too small, and the lubricating oil contains impurities that cause abnormal wear such as fraying of the bearing shells, resulting in frictional heat.
Excessive exhaust temperature: Excessive exhaust temperature leads to an increase in oil temperature.
6. Compressor fuel consumption
Wear of piston rings, oil rings, and cylinder liners: leading to poor sealing and leakage of lubricating oil.
Reverse installation of oil ring or improper installation of locking port: resulting in the inability of lubricating oil to circulate normally.
Excessive exhaust temperature: causing the lubricating oil to vaporize and be carried away.
Shaft seal oil leakage: Oil leakage is caused by damaged or poorly assembled shaft seal components.
7. Compressor wet stroke
Excessive opening of throttle valve: supplying too much liquid to the evaporator or low-pressure circulation tank, resulting in a supply volume greater than the evaporation volume.
Opening the suction valve too quickly when starting the compressor: causing a large amount of liquid refrigerant to enter the compressor.
Delayed defrosting of evaporator: Oil accumulation inside the evaporator and external frosting result in a decrease in heat transfer efficiency.
8. There is a knocking sound in the crankcase
The clearance between the connecting rod big end bearing and the crankshaft journal is too large, causing a collision sound between the bearing and the crankshaft journal.
Excessive clearance between the main bearing and the main journal can also cause impact noise.
Broken split pin or loose connecting rod bolt: causing the connecting rod components to loosen and produce impact sound.
9. Other common faults
Energy regulation failure: The energy regulation mechanism fails due to low oil pressure, blocked oil pipes, stuck oil pistons, and other reasons.
High exhaust temperature: In addition to the high oil temperature mentioned above, high exhaust temperature may also be caused by high condensation pressure, high suction superheat, and other reasons.
Low suction pressure of the compressor: caused by insufficient liquid supply, incomplete opening of valves in the suction pipeline, or detachment of valve cores.
In summary, piston compressors may encounter various malfunctions during use. In order to ensure the normal operation and prolong the service life of the compressor, regular maintenance and upkeep work should be carried out, and faults should be dealt with in a timely manner.
Here are some corresponding solutions to common faults in piston compressors:
1. The compressor cannot start and operate normally
Check the power supply: Ensure that the power supply is normal, the voltage is stable, and there is no phase loss phenomenon.
Check electrical circuits: Check for loose connections in fuses and contactors, and promptly tighten or replace damaged components.
Inspect the motor: Conduct a comprehensive inspection of the motor, including components such as windings and bearings, and promptly repair or replace damaged parts.
Reduce crankcase pressure: Check and repair issues such as exhaust valve leakage and energy regulation mechanism malfunction to ensure normal crankcase pressure.
Adjust energy load level: Adjust the energy load level of the compressor to an appropriate position to avoid being too high or too low.
Check and repair the temperature controller: Ensure that the temperature controller is working properly and the set values are reasonable.
Check and repair the pressure relay: Adjust the set value of the pressure relay to ensure its normal operation.
Establish normal oil pressure: Check the oil pump, oil pipe, and other components to ensure smooth oil flow and stable oil pressure.
Check and repair the cooling water or refrigerant water system: Ensure that the cooling water or refrigerant water supply is normal and the water flow relay is working properly.
2. Sudden shutdown of compressor during normal operation
Check the power supply: Ensure that the power supply is not disconnected and the voltage is stable.
Check alarm information: Based on the alarm information, check and repair corresponding faults, such as main motor overload protection shutdown, exhaust pressure high alarm shutdown, etc.
3. Low oil pressure
Clean and unclog the oil pipe: Clean the blockage in the oil pump pipeline to ensure that the oil pipe is unobstructed.
Check and repair the oil pressure regulating valve: Adjust the oil pressure regulating valve to ensure its normal operation.
Supplement lubricating oil: Timely supplement the lubricating oil in the crankcase to ensure the oil level is normal.
Exclude ammonia liquid from the crankcase: If the oil pressure drops due to fluid entering the crankcase, the ammonia liquid needs to be removed and new lubricating oil needs to be replaced.
Check and repair the oil pump: Disassemble and inspect the oil pump, repair or replace damaged parts.
Inspect and repair connecting rod bearings and main bearings: Inspect and repair severely worn connecting rod bearings and main bearings and other components.
4. Foam in crankcase
Remove the ammonia liquid from the crankcase: If a large amount of liquid is injected into the crankcase and foam is generated, remove the ammonia liquid.
Drain too much lubricating oil: if foam is generated due to too much oil filling in the crankcase, drain too much lubricating oil.
5. Oil temperature too high
Check the cooling water system: Ensure that the cooling water supply is normal, the water temperature is appropriate, and the water volume is sufficient.
Adjust the assembly clearance between the bearing shell and the bearing: Adjust the assembly clearance between the bearing shell and the bearing to a reasonable range to avoid abnormal wear.
Reduce exhaust temperature: Check and repair the causes of high exhaust temperature, such as condenser failure, high suction superheat, etc.
6. Compressor fuel consumption
Check and replace piston rings, oil rings, cylinder liners: Check and replace severely worn piston rings, oil rings, cylinder liners, and other components.
Reinstall the oil ring: If the oil ring is installed incorrectly or the locking port is installed improperly, the oil ring needs to be reassembled.
Reduce exhaust temperature: Reduce exhaust temperature to avoid lubricating oil vaporization and being carried away.
Check and repair the shaft seal: Check and repair the shaft seal components to ensure good sealing performance.
7. Compressor wet stroke
Adjust the opening degree of the throttle valve: Reasonably adjust the opening degree of the throttle valve to avoid excessive liquid supply.
Slowly open the suction valve: When starting the compressor, slowly open the suction valve to avoid a large amount of liquid refrigerant entering the compressor.
Timely defrosting: Regularly defrost to ensure that there is no oil accumulation inside the evaporator and no frosting outside.
8. Other common troubleshooting methods
Check and repair the energy regulation mechanism: Check and repair the causes of energy regulation failure, such as low oil pressure, blocked oil pipes, etc.
Reduce exhaust temperature: In addition to the exhaust temperature caused by high oil temperature mentioned above, it is also necessary to check and repair components such as the condenser and suction pipe to ensure that the exhaust temperature is normal.
Increase the suction pressure of the compressor: Check and repair problems such as insufficient liquid supply, incomplete opening of valves in the suction pipeline, or detachment of valve cores to increase the suction pressure of the compressor.
In summary, corresponding solutions need to be taken to repair common faults in piston compressors. During the maintenance process, relevant operating procedures and safety standards should be strictly followed to ensure maintenance quality and personnel safety. At the same time, regular maintenance and upkeep of the compressor is also an important measure to prevent malfunctions from occurring.
