Refrigeration oil is used to lubricate the moving parts in refrigeration compressors. It is called refrigeration oil, also known as lubricating oil. Do you need to replace the refrigeration oil of the compressor of the central air-conditioning unit once a year? What are the steps to replace the refrigeration oil? Next, follow the CRR Intercooler to find out!
I. The role of compressor refrigeration oil
How to change the refrigeration oil of central air-conditioning?
1, Lubrication
It can lubricate the surface of the moving parts of the compressor, reduce resistance and friction, reduce power consumption, and extend service life.
2, cooling effect
It can take away the heat generated by the friction of the moving surface in time to prevent the temperature of the compressor from rising too high or the compressor from being burnt out.
3. Sealing effect
Lubricating oil penetrates into the sealing surfaces of each friction member to form an oil seal, which prevents the leakage of refrigerant.
4. Reduce compressor noise
The lubricating oil continuously flushes the friction surface and removes the wear debris, which can reduce the wear of the friction parts.
2. Under what circumstances need to replace the special refrigeration oil
How to change the refrigeration oil of central air-conditioning?
Whether the central air conditioner needs to be replaced with refrigeration oil is determined based on the indicators, mainly the following indicators:
1, PH value index
When the pH value of the lubricant is below 6, you need to consider replacing the refrigeration oil, because the acidification of the lubricant will directly corrode the equipment and affect the life of the compressor motor. It is recommended that you regularly check the pH value of the refrigeration oil. The drying filter of the system should be replaced regularly to keep the system dryness under normal conditions.
2, pollution index
If more than 5mg of contaminants are detected per 100ml of refrigerated oil, it is recommended to replace them.
3. Water content
If the water content in the frozen oil exceeds 100 ppm, the frozen oil needs to be replaced.
III. Specifications for replacing refrigerated oil
How to change the refrigeration oil of central air-conditioning?
1. Close the high-pressure exhaust and low-pressure suction cut-off valves, and use the process valve needle on the press to release the refrigerant inside the press, so that the crankshaft of the shrinking machine communicates with the atmosphere.
2. Unscrew the drain plug at the bottom case of the crankcase, drain the frozen oil in the crankcase, and remove the filter to clean it.
3. Nitrogen can be blown in from the low-pressure inflation valve needle, and the oil drain port can be blocked by hand to increase the pressure inside the machine body to further remove the residual oil in the machine body. Dry the cleaned filter into the machine body and tighten the oil drain plug. .
4. What are the requirements for refrigeration oil for refrigeration equipment compressors?
How to change the refrigeration oil of central air-conditioning?
Because of different applications and refrigerants, the choice of refrigeration oil for refrigeration equipment is different. The requirements for refrigeration oil are as follows:
1. Viscosity of frozen oil An important parameter in the characteristics of viscosity oil, the use of different refrigerants should choose different refrigeration oils accordingly. If the freezing oil viscosity is too large, the mechanical friction power, friction heat and starting torque will increase. Conversely, if the viscosity is too small, the required oil film cannot be formed between the moving parts, and the proper lubrication and cooling effects cannot be achieved.
2. Cloud point The cloud point of refrigerated oil refers to the temperature at which the paraffin starts to precipitate in the refrigerated oil when the temperature drops to a certain value, making the lubricating oil cloudy. The cloud point of the refrigeration oil used in refrigeration equipment should be lower than the evaporation temperature of the refrigerant, otherwise the throttle valve will be blocked or the heat transfer performance will be affected.
3. Freezing point The temperature at which the frozen oil cools to stop flowing under the experimental conditions is called the freezing point. The freezing point of the refrigerating oil used in refrigeration equipment should be as low as possible (such as the compressor of R22, the refrigerating oil should be below -55 ° C), otherwise it will affect the refrigerant flow, increase the flow resistance, and lead to the consequence of poor heat transfer effect.
4. Flash point The flash point of refrigerated oil refers to the temperature at which the lubricating oil will ignite when its steam is in contact with the flame. The flash point of the refrigerating oil used in refrigeration equipment must be higher than the exhaust temperature by 15-30 ° C, so as not to cause the combustion and coking of the lubricating oil.
5. Others such as chemical stability and oxygen resistance, moisture and mechanical impurities, and insulation properties.
The above is the complete content of the article "How to Change the Refrigeration Oil of Central Air Conditioning" by CRR Intercool. I hope you have a certain understanding of "How to Change the Refrigeration Oil of Central Air Conditioning" after reading
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