Replacement Operation and Common Fault Causes of Vortex Compressor

Replacement Operation and Common Fault Causes of Vortex Compressor

Step 1: Electrical inspection of the compressor

Voltage and current measurement: The output terminal of the AC contactor of the compressor is used to determine whether the power supply voltage and starting voltage of the compressor are within the normal range.

Insulation resistance: The ground resistance of the compressor terminal can generally be tested between the compressor terminal and the copper tube on the compressor using the ohm range (40 megohm range) of a megohmmeter or multimeter. It is generally above 40 megohms. If there is liquid refrigerant or high air humidity inside the compressor, the insulation resistance value will be lower.

Step 2: Replace the faulty compressor

When welding down system components, the refrigerant should be discharged first, and the refrigerant should be discharged from both the high-pressure and low-pressure sides simultaneously. If carried out only from the high-pressure side, the vortex sealing will cause the refrigerant to remain on the low-pressure side. When the connecting pipe is welded down, the mixture of refrigerant and oil will spray out and ignite when exposed to flames.

If it is necessary to replace the compressor, the connecting pipes on both sides of the compressor must be cut off before removing the compressor.

If the compressor is damaged due to the burning of the motor, the degree of contamination of the lubricating oil should be checked. Before replacing the compressor, both the gas-liquid separator and the drying filter should be replaced, and a drying filter should be added on the suction side. After allowing the system to run for a period of time, the contamination level of the filter core should be checked to determine whether the filter needs to continue cleaning the system.

Step 3: Storage and handling of the new compressor

During the transportation of a new compressor, the compressor should be kept vertical. Excessive tilting, lying or overturning of the compressor can cause a large amount of lubricating oil to enter the vortex plate, which may cause oil to spray out or temporarily fail to start when opening the sealing plug.

Step 4: Remove the sealing plug and secure the foot

The compressor is filled with dry air at a certain pressure when leaving the factory, and then sealed with a sealed rubber plug to ensure cleanliness and dryness. As the suction pipe is close to the oil level, the exhaust plug should be removed before installation, followed by the suction plug. Clean the inner ring of the suction pipe with a cloth, wipe off the oil film layer, and facilitate welding.

Place the steel sleeves separately into the fixing bolts, then lift the compressor into the installation position, and gently tighten the nuts with washers. When tightening the nuts with washers, if force is applied, it will cause the sleeves to tilt or even break, which will cause vibration and noise.

Step 5: Welding of compressor suction and exhaust pipes

Attention! Many compressor suction and exhaust pipes are made of copper plated steel pipes, and it is best to use solder containing at least 5% silver. If using solder containing less than 2% silver, excellent skills should be used to ensure that the solder does not enter the compressor and cause malfunctions. During welding, a small amount of nitrogen should be introduced to prevent the generation of oxides, which may fall into the compressor and cause malfunctions. Do not overheat the pipe opening, and the welding time should be 15-20 seconds.

Step 6: Vacuum pumping

The presence of air, also known as non condensable gases, poses great harm to refrigeration systems. Without vacuum pumping, refrigeration systems typically exhibit an increase in condensation pressure, condensation temperature, compressor exhaust temperature, and power consumption. At the same time, high exhaust temperature may cause carbonization of lubricating oil, affecting lubrication efficiency, and in severe cases, burning out the refrigeration compressor motor.

When vacuuming, both the high-pressure and low-pressure sides should be carried out simultaneously. The vacuum degree should be read using a dedicated vacuum gauge, and the normal system vacuum degree should be below -756mm Hg. The vacuum pumping time should be determined based on the size of the refrigeration system of the model and the size of the vacuum pump.

Step 7: Refrigerant Charging

Firstly, it is necessary to confirm whether the refrigerant model matches the refrigerant labeled on the external unit, and then charge from the high-pressure side. If only filled from the low-pressure side, it may cause the axial seal of the vortex disc to temporarily fail to start.

If it is not possible to achieve the required filling amount at once, try to reach 70%~75% of the total filling amount before the first startup. Then, when starting up and filling, closely observe the pressure, current, defrosting, temperature, etc. of the refrigerant system, and decide whether to continue to add a small amount to achieve the optimal efficiency. If the system has a nameplate indicating the refrigerant charging amount, it should be weighed and filled.

Step 8: Electrical Connection

Press the hooks on both sides of the electrical box cover inward to open it. There is a 50% possibility of reversing the wiring of the three-phase vortex compressor. At this time, the high and low pressure of the system will not change, and the suction will not be cold and the exhaust will not be hot. As long as the wiring of any two phases in the three-phase is swapped, this fault can be eliminated. Short term reversal will not cause any problems.

For terminals connected with screws, be careful not to apply excessive force to prevent damage to the internal threads of the terminals or screw breakage. It is generally not necessary to add refrigeration oil when replacing the compressor, as the new compressor has already been filled with oil. If there are special circumstances, such as the installation of long connecting pipes, and it is necessary to add refrigeration oil, such as when the refrigerant is R22, the grade of the refrigeration oil is 3GS.

                                                       Common faults and analysis of vortex compressors

Common fault 1: compressor oil shortage and insufficient lubrication of the compressor
The reasons are as follows:
The compressor frequently starts and stops for a long time.
The system contains air or moisture.
System return or refrigerant migration dilutes lubricating oil.
Reverse rotation of the compressor (such as incorrect phase sequence)
The leakage of refrigerant in the system results in insufficient lubricating oil for the compressor.
There are other chemical substances in the system that react with the lubricating oil, causing it to deteriorate.

Common Fault 2: Compressor Hydraulic Shock
The reasons are as follows:
Excessive refrigerant addition leads to a large amount of liquid return in the system.
The internal fan does not rotate and the air volume is small, resulting in incomplete refrigerant evaporation.
When the power is cut off, the solenoid valve still maintains a certain opening, causing a large amount of liquid return in the system.
Excessive oil addition leads to system oil shock (low-pressure chamber compressor).

Common fault 3: High temperature burning of the compressor
The reasons are as follows:
The vacuum level of the system is insufficient.
Insufficient refrigerant addition or refrigerant leakage.
The system's return air duct is blocked by ice, resulting in high exhaust or top temperature.
If the connecting piping is too long or the diameter is small, the system resistance increases, leading to an increase in exhaust temperature and pressure.

Common Fault 4: Compressor Motor Damaged
The reasons are as follows:
Burning or abnormality of contactor contacts, such as phase loss or deviation.
± 10% of the rated voltage of the power supply that cannot be exceeded; The three-phase voltage imbalance rate cannot exceed 3%.
Insufficient cooling of the motor, large refrigerant leakage or low evaporation pressure can cause a decrease in system mass flow rate, making it difficult for the motor to receive good cooling.