Don't guess randomly when the compressor is damaged, 90% of the problems are concentrated in these aspects

Most of the compressor failure problems are caused by the following aspects: poor oil return, oil shortage, hydraulic compression, fluorine-deficient operation, exhaust gas overheating, and poor system cleanliness. According to statistics, the faults caused by these problems account for more than 90% of the total failure rate, and the common causes of failure are explained as follows.

1. Damage caused by poor oil return (lack of oil) of the compressor
It is crucial to ensure adequate refrigeration oil lubrication during compressor operation. If the refrigeration oil is insufficient, the mechanical parts will wear and tear due to the lack of effective lubrication, which may eventually lead to the compressor burn.

When the system returns poorly (oil shortage), the compressor cannot transport enough oil to each lubricating part, causing the friction force in each part to gradually increase from bottom to top. Among them, the uppermost moving disc sleeve and the crank pin are most severely affected because the force is several times that of the other two lubricating parts at the lower part. The heat generated by friction will heat up the moving disc sleeve, which will eventually cause the sleeve to burn or even get stuck. In extreme cases, the sleeve can be severely worn and broken. At this time, the increase in the motor temperature will cause the protector to operate frequently, which will eventually lead to the protector failure. Continuous high currents act on compressors that lose protection, which will cause the motor winding to burn.

Specific causes of poor oil return (oil shortage)
Improper startup and debugging: If the refrigeration pipeline is long, if sufficient lubricating oil is not added during startup and debugging, the system will be insufficient oil return.
Improper maintenance: If the air-conditioning refrigerant frequently leaks refrigerant in the air conditioning refrigeration system, the lubricant will also leak. If the refrigeration oil is not replenished in time, it will cause the system to lack oil.
Improper design and installation: Unreasonable oil return design often occurs in projects, such as not installing the oil return bend at the bottom, the diameter of the air pipe is too large, and the distance between the oil return bends is too far, etc., which will affect the oil return effect of the system.
Improper design selection: If the compressor is unreasonable, it will cause frequent start and stop and the continuous operation time is too short, and a stable high-speed air flow cannot be formed in the air pipe, and the lubricating oil will remain in the pipeline and cannot return to the compressor.
Improper operation of replacing the compressor: If refrigeration oil is not added when replacing the new compressor, it will cause poor lubrication of the system compressor and damage the compressor.

2. Damage caused by hydraulic compression
After the liquid refrigerant enters the compressor, hydraulic compression will occur, resulting in the breaking of the dynamic and static disk scroll. When the liquid refrigerant enters the compressor cavity for compression, the scroll will be subjected to extremely high lateral shear force due to the incompressible liquid, which will break the systolic scroll and the compressor will be stuck. In addition, if the broken fragments fall on the motor, it will cause the motor to burn out in a short circuit.

The main reasons for hydraulic compression include the system evaporator side fan not rotating or the pipeline is blocked, leakage of fluid from the electronic expansion valve of the refrigeration mode, excessive refrigerant filling during maintenance or installation, etc. To avoid hydraulic compression, the appropriate amount of refrigerant needs to be adjusted to ensure that the heating belt at the lower part of the compressor is normally energized. For air conditioners that are placed for a long time or in a low temperature environment, preheat for 8 hours before starting.

3. Long-term fluorine deficiency operation leads to damage to the compressor
When the compressor is running in a fluorine-deficient state, the temperature in the center of the dynamic and static disk will rise sharply. When the temperature reaches a certain level, the end sealing ring will melt and its melting substance will adhere to the dynamic and static disks, increasing the friction of the dynamic and static disks. In severe cases, the dynamic and static disk will be stuck or broken, and the motor temperature will also rise, causing the IP to operate frequently, the protector to fail, and eventually the motor to burn. In addition, carbonization of the O-ring will cause high and low pressure failure, and the exhaust pressure will decrease when the compressor is powered on and started.

Fluorine deficiency operation is usually caused by insufficient fluorine deficiency or insufficient fluorine charge in the air conditioning system. In addition, poor installation and leakage at system connectors may also cause fluorine deficiency problems. Therefore, after installing the maintenance equipment, you need to carefully check whether there are leakages in each pipe joint and welding area.

4. Poor system cleanliness causes damage to the compressor
If the system is not clean, the refrigeration compressor may experience shaft holding, poor insulation, copper plating and other phenomena. During the welding process, special attention should be paid to prevent debris, water rust and moisture from entering the system. Because these substances are easily reacted after contacting refrigerant or refrigerant oil, chemical reactions occur, resulting in deterioration of the motor insulation inside the compressor. If these substances enter the oil supply system of the compressor, the movable part will stick, causing the shaft to be held. Therefore, during installation, you need to pay attention to pipeline maintenance to prevent foreign objects from entering the pipeline.

Common causes of overheating of compressor exhaust
Refrigerant leakage;
There is air and moisture in the system;
The evaporator or condenser is dirty and blocked, causing the refrigerant circulation to be blocked;
Too much or too little compressor oil will cause the compressor exhaust temperature to rise;
The cooling fan motor burns out or poor heat dissipation will also increase the compressor exhaust temperature.

Shanghai KUB Refrigeration Equipment Co., Ltd.

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