We have previously published an analysis of the causes of compressor coil burnout. Today, let's talk about how to deal with a compressor burnout? Can we directly replace it with a new compressor?
1. Correct Operation after Compressor Burnout
For the correct operation process, you can refer to the following operations:
1.1 Step 1: Release the Refrigerant
To release the refrigerant in the system, it should be released from both the high-pressure and low-pressure sides of the system. If it is discharged from only one side, the vortex seal will cause incomplete release.
The speed of releasing the refrigerant should not be too fast, otherwise a large amount of lubricating oil (refrigeration oil) will be taken out of the system with the refrigerant.
1.2 Step 2: Remove the Compressor
After confirming that the compressor is damaged and needs to be replaced, first disconnect the outdoor unit power supply switch, disconnect the compressor power supply wiring and seal it with insulating tape. Then remove the compressor.
1.3 Step 3: Replace the Gas-Liquid Separator
When the refrigeration system is oil-contaminated, the gas-liquid separator should be replaced at the same time, regardless of whether there are impurities or other abnormalities in the gas-liquid separator.
1. Unsolder and disconnect the inlet and outlet pipes of the gas-liquid separator;
2. Remove the bolts that fix the gas-liquid separator;
3. Take out the gas-liquid separator.
1.4 Step 4: Clean the Pipeline System
After confirming the parts that need to be replaced, it is necessary to check whether the system pipeline is abnormal. Then use nitrogen to purge the main pipeline, and at the same time, focus on detecting and cleaning the oil system.
1.5 Step 5: Replace the Compressor
Before installing the new compressor, remove the rubber plugs and weld the inlet and outlet of the compressor with the corresponding pipes. During the welding process, nitrogen needs to be introduced into the pipeline. Because the compressor suction and discharge ports are copper-plated steel pipes, solder containing at least 5% silver needs to be used. Do not overheat the pipe during welding.
After welding the pipeline system, it is necessary to use special pads and bolts to fix the compressor to ensure the stability of it during operation, and make sure that the position and wiring of it are correct.
1.6 Step 6: System Leakage Detection
First, check each weld to see if they are smooth and whether there are obvious abnormal conditions such as welding holes. Then fill the unit system with high-pressure nitrogen to check for leaks.
If only the external unit needs repairing and it can be confirmed that there is no abnormality in the internal unit system, only the external unit can be filled with high-pressure nitrogen for leak detection.
Note that nitrogen needs to be filled from both the high and low pressure sides at the same time, and the nitrogen pressure should be greater than 20kgf. Then use soapy water to check for leaks in the unit system, and focus on checking and repairing solder joints.
1.7 Step 7: Evacuate the System
After evacuating the system, make sure that the pressure of the system can reach an absolute pressure of 0kgf/cm2 and a gauge pressure of -1kgf/cm2, because only when the absolute pressure reaches 0kgf/cm2 can the water in the pipeline system be completely evaporated.
1.8 Step 8: Add Refrigeration Oil
The amount of refrigeration oil that needs to be added to the system is mainly decided by the total amount of lubricating oil poured out by removing the compressor, gas-liquid separator and other components, that is, how much is poured out and how much is added.
1.9 Step 9: Charging the Refrigerant
After evacuating the system and adding the refrigeration oil, the system is ready for refrigerant charging.
● Connect the refrigerant cylinder to the system's service port using a manifold gauge set and hoses.
● Open the refrigerant cylinder valve and slowly introduce the refrigerant into the system.
● Monitor the pressure and temperature using the manifold gauge set to ensure proper charging.
● Refer to the system's specifications or manufacturer guidelines for the recommended refrigerant type and charge amount.
1.10 Step 10: Connect Electrical Components
According to the previous markings and the circuit diagram behind the electrical box cover, connect the compressor line correctly. Be sure to check carefully according to the electrical wiring diagram to ensure that the wiring is correct!
1.11 Step 11: Start and Test the Unit
Start the unit, and let it perform cooling and heating condition operations. Each condition requires more than 30 minutes of operation, and the data should be analyzed and the unit system needs adjusting to ensure that all parameters are normal.
2. Consequences of Replacing the Compressor without Fully Cleaning the System
The results of directly installing the new compressor without cleaning the system are as follows:
1. It is impossible to completely remove impurities in the system by evacuating the system, and the vacuum pump is also easily damaged.
2. After adding the new refrigerant, it only plays the function of cleaning system parts, and the pollution of the whole system still exists.
3. The new compressor, refrigeration oil, and refrigerant is immediately contaminated within 0.5-1 hours. The second contamination process begins immediately as follows:
1) After the refrigeration oil is impure, it begins to destroy the original lubrication properties.
2) Dirty metallic powder entering the compressor may penetrate the motor insulation film and cause a short circuit, resulting in re-burning.
3) Dirty metallic powder sinks into the oil, causing increased friction between the shaft and sleeve or among other moving parts, and the compressor may be stuck.
4) After the refrigerant, oil, original pollutants, and acidic substances are mixed, more acidic substances and water are produced.
5) Copper plating occurs, the mechanical clearance is reduced, and friction is increased and the compressor is stuck.
4. If the original dryer is not replaced, the original moisture and acidic substances will be released.
5. Acidic substances will slowly corrode the surface insulation film of the motor enameled wire.
6. The cooling effect of the refrigerant itself is reduced.
Under the above conditions, the new compressor will be completely burned out within about 1 month. If you encounter continuous faults such as compressor motor coil burning, compressor stuck, and coil burning again, you must clean or purge the compressor.
