Understand These Refrigeration Knowledge to Boost Your Style!

2025-03-11

Why should the impurity content and moisture content in the compressor and the air conditioning system be controlled?
When impurities enter the friction surfaces of the moving parts inside the compressor pump body, abnormal scratches and wear will occur. When impurities enter the solenoid valve, expansion valve, control valve, capillary tube and stop valve in the air conditioning system, they will block the valve holes or make the valves unable to close tightly and thus fail.
The moisture in the compressor and the air conditioning system mainly has the following adverse effects:
The capillary tube and the expansion valve will be blocked by ice, and the cooling tubes of the evaporator will also freeze;
The metal materials will be corroded and deposits will be generated;
The valve core will be corroded and fail to close tightly;
The phenomenon of "copper plating" will occur on the surface of the compressor pump body parts;
It will accelerate the deterioration of materials such as insulating materials, refrigerant, and refrigeration oil.
Excessive moisture content.
What impact will a low voltage have on the air conditioning system?
If the voltage is too low, far below the specified operating voltage range of the compressor, since the locked-rotor current value is likely to fail to reach the operating current specification of the protector, the protector will not be able to act in a timely manner, causing the compressor motor to overheat and even burn out.
What is the function and principle of the compressor protector?
The function of the compressor protector is mainly to protect the compressor from accidents such as motor burnout when it is in an abnormal situation.
The main principle: It relies on the combined effect of the heating wire inside the protector and the internal resistance of the bimetallic strip generating heat through the current and the external conduction of heat to make the bimetallic strip act, thus cutting off the circuit and protecting the compressor from damage.
How to make basic judgment and handling after the compressor malfunctions?
Unable to start, no suction and discharge pressure: First, detect the compressor wiring, pipeline connection, and basic items such as the impedance of the main and auxiliary coils and the insulation withstand voltage of the compressor. If everything is normal, it is recommended to remove the compressor and perform an idling test to check if there is suction and discharge.
The method of suction and discharge is: When the compressor is running, press your finger against the exhaust port for a few seconds, and then release it to observe if there is gas ejected. It is normal to have a small amount of oil ejected. If there is suction and discharge and the discharge pressure is high, it indicates that the compressor can work normally; otherwise, the compressor is abnormal.
Why is it necessary to prohibit the liquid refrigerant from flowing back into the compressor suction chamber?
If the liquid refrigerant directly enters the compressor suction chamber, during the rotation of the crankshaft, the volume of the compressor becomes smaller and smaller, and the pressure rises sharply, causing the pump body parts and valve plates to bear abnormal forces or even be damaged. Liquid hammer will also cause abnormal vibration and noise of the compressor.

In addition, when the liquid refrigerant enters the cylinder, it will "wash away" the lubricating oil on the surfaces of parts such as the piston and blades, resulting in a situation equivalent to "running without oil", causing abnormal wear and even compressor seizure.
Abnormal wear.
Why should the refrigerant recovery time of the air conditioner not be too long?
The refrigerant recovery operation time of the air conditioner should not be too long. Because after the refrigerant recovery time is too long, due to the extremely thin refrigerant gas inhaled, the exhaust temperature will be very high, causing the temperature of the compressor pump body components to rise rapidly. When the temperature is too high, the expansion degrees of various parts differ too much, causing the fit clearance of some parts to become smaller or even disappear, ultimately resulting in abnormal scratches or wear.
What is the impact of wrong wiring of the compressor? Why can't the protector provide protection?
Wrong wiring of the compressor will make it unable to work normally. According to different wrong wiring methods, phenomena such as locked-rotor, reverse rotation, and stopping after starting will occur, and it is very likely to cause the direct burnout of the compressor motor.
Since the compressor protector is selected according to the working characteristics of the protector under abnormal working conditions when the compressor is correctly wired, it cannot ensure the protection of the compressor when the wiring is wrong. It is difficult to protect the motor through the protector in the case of wrong wiring.
For the same system, is it necessary to adjust the system when replacing the compressor with one from a different manufacturer?
Since the performance characteristics of compressors produced by different companies are different, for a specific compressor, its best performance can only be shown under specific conditions such as refrigerant flow rate, suction and discharge pressure, and temperature.
Therefore, when using different compressors in the same air conditioning system, it is best to adjust the system separately to ensure that the used compressor works normally under appropriate refrigerant flow rate, suction and discharge pressure, and temperature conditions. In this way, the service life of the compressor can be effectively extended and the best use effect can be achieved.
Why is there a requirement for the temperature of the compressor motor coil during operation?
It is determined by the insulation class (Insulation classes: A (105°C), E (120°C), B (130°C), F (155°C), H (175°C)) and heat resistance characteristics of the insulation materials used in the compressor motor. For the motor enameled wire, too high a temperature will lead to a decrease in the film quality, a reduction in abrasion resistance, easy peeling, a decrease in the insulation breakdown voltage and insulation impedance, etc., thus greatly reducing the service life.
In addition, too high a motor temperature can cause excessive dissolution of polymers in the insulation material, and these substances will precipitate and accumulate somewhere in the system or at the compressor exhaust port, etc., affecting the performance of the compressor and the system.
Moreover, too high a coil temperature will reduce the efficiency of the compressor motor.
Why should the compressor be stopped for at least 3 minutes after shutdown before it can be started again?
When the compressor starts, a large amount of refrigeration oil will enter the air conditioner system along with the refrigerant circulation. If there is not enough running time, the refrigeration oil will not be able to return to the compressor cavity in time. Frequently stopping the compressor soon after starting will lead to a low oil level inside the compressor, which is likely to cause poor lubrication of the mechanical moving parts of the compressor.
In addition, the shutdown time of more than 3 minutes is mainly to give the system enough time for pressure balance. Otherwise, due to the existence of high and low pressures, the compressor will not be able to start normally.
Why can't the compressor operate under "vacuum conditions"?
The so-called "vacuum conditions" are not an absolute vacuum state, but a state of extremely low air pressure. Gas molecules will ionize under extremely low pressure.
According to the actual experimental results, the breakdown voltage of the compressor terminals is the lowest when the internal pressure of the compressor is around 3.5mmHg. When energized, breakdown and internal carbon deposition are likely to occur, damaging the insulation of the hermetic terminal. In severe cases, the hermetic terminal may burn out and fly out during the operation of the compressor. Therefore, energizing the compressor in a vacuum state should be avoided.