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Refrigerants are also called refrigeration working fluids, commonly known as refrigerants in some areas in the south. It is a working substance that continuously circulates in the refrigeration system and realizes refrigeration through its own state changes. The refrigerant absorbs the heat of the cooling medium (water or air, etc.) in the evaporator to vaporize, and transfers the heat to the surrounding air or water in the condenser to condense.

In gas compression refrigerators, gas refrigerants such as air, hydrogen, helium, etc. are used. These gases are always gaseous in the refrigeration cycle; in absorption refrigerators, a binary composition composed of absorbent and refrigerant is used. Solution is used as working fluid, such as ammonia and water, silver bromide and water, etc.; steam jet refrigerator uses water as refrigerant. The main technical indicators of refrigerants include saturated vapor pressure, specific heat, viscosity, thermal conductivity, surface tension, etc. After 1960, people have conducted a large number of experimental studies on the application of non-azeotropic mixtures, and they have been used in the liquefaction and separation of natural gas. The application of single-stage compression of non-azeotropic mixed working fluid can obtain very low evaporation temperature, and can increase refrigeration capacity and reduce power consumption. Its nature is directly related to the refrigeration effect, economy, safety and operation management of the refrigeration device.

Because R22 and R410A have different compositions and pressures, R410A needs to be filled in liquid, and the thickness of the copper tube of the machine is also different, so it is forbidden to mix the two refrigerants. Maintenance measuring instruments and quantitative refrigerant charging equipment should also be dedicated.

According to the air-conditioning installation or maintenance process (national standard or industry-related standard): when the connecting pipe between indoor and outdoor units of air-conditioning installation exceeds the standard length by more than 5 meters, the refrigerant should be refilled in time. The operation effect is not good.

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R410A is a HFCs refrigerant mixed with two working fluids of R32 and R125 at a mass fraction of 1:1. Compared with R22, the condensation pressure of R410A is about 1.6 times that of R22. It is a high-pressure refrigerant and needs to improve the pressure resistance of the system. Compared with R410A, the saturation pressure of R32 refrigerant is about 2.5% higher.

Ten prohibitions on installation and maintenance of flammable refrigerant air-conditioning

1. It is strictly forbidden to engage in special operations without qualification certificates;

2. It is strictly forbidden to work at altitudes above 2m without wearing a safety belt or a safety rope;

3. It is strictly forbidden to smoke at the installation and maintenance site, and there should be no fire or high temperature heat source within two meters;

4. It is strictly prohibited to install without vacuuming or the vacuuming time is less than the specification requirements;

5. It is strictly forbidden to replace nitrogen with oxygen to maintain system pressure;

6. It is strictly forbidden to start and run the outdoor unilateral machine;

7. It is strictly forbidden to conduct welding repairs and use open flames or pipes with refrigerant in the welding system in the user's home;

8. It is strictly forbidden to recover the refrigerant under the negative pressure of the system, and the recovery time shall not exceed 1 minute;

9. It is strictly forbidden to use fake refrigerants, inferior refrigerants and different types of refrigerants to mix or substitute;

10. It is strictly forbidden to detect the system pressure in the startup state. In the standby state, the detection system pressure range is normal, and it can be powered on when there is no negative pressure.

The refrigerant will inevitably not decrease after the automobile air conditioner is used for a long time. The high pressure Car Refrigerant charging pipe end charging method means that the refrigerant is added to the system from the high pressure end of the air conditioning system.

R12, R134, R410 refrigerant and liquid tricolor tube
① As shown in the figure, connect the manifold pressure gauge group with the system maintenance valve and refrigerant tank.
② Use the refrigerant to remove the air in the connecting hose. The specific method is: first close the high and low pressure manual valves, disconnect the high pressure end inspection valve and the hose connection, then open the high pressure manual valve, and finally open the valve. When the refrigerant gas is discharged from the Charging Pipe , quickly connect the hose to the maintenance valve and close the high-pressure manual valve. Use the same method to remove the air in the connecting hose at the low pressure end, and then close the high and low pressure manual valves and the valves on the refrigerant cylinders.
③ Put the refrigerant tank upside down on the scale and record the initial mass.
④ Open the valve on the refrigerant bottle, and then slowly open the high-pressure manual valve. The refrigerant is injected into the system. When the scale indicates that the specified quality is reached, the refrigerant valve is quickly closed.
⑤ Close the high-pressure manual valve and the filling ends.