2.Refrigerant: Open the high and low pressure side valves with the inner hexagon, pay attention to the ventilation of the working environment, so as not to suffocate the operator; the speed of the refrigerant should not be too fast, so as to prevent the operating staff from being frostbited by the refrigerant. If possible, the refrigerant should be recycled instead of directly discharged to protect the environment.
3. Remove the suction and exhaust pipes: Before removing the suction and exhaust pipes, ensure that the refrigerant in the system has been exhausted.
4. Replace the compressor, and connect the suction and exhaust pipes: Replace with a new compressor, and the inclination angle of the compressor should not be greater than 45° during the transportation of the compressor.
To remove the compressor rubber plug, you must first exhaust the pipe and then the suction pipe. The interval between removing the rubber plug and welding the pipe should not exceed 10 minutes to prevent air moisture and impurities from entering the system and affecting the performance of the unit.
V. Pressure-holding leak detection: After the suction and exhaust pipes are welded, pressure-holding and leak detection are required. The gas used to maintain pressure can only be inert gas such as nitrogen and carbon dioxide. It is strictly forbidden to substitute air, oxygen, acetylene, refrigerant, etc. to avoid safety accidents.
Before pressure suppression, the pressure detection instrument should be connected to the system pressure test leak detection pipeline, and the compressed gas cylinder should be connected according to the safety requirements. The R22 system is about 2.6MPa and the R410a system is about 3.8MPa. After 24 hours, the pressure drop is within 0.02MPa. qualified.
6. Vacuum: Before any system needs to be filled with refrigerant after installation, pressure maintaining and leak detection, the system must be vacuumed to exhaust the air and moisture in the system.
It is strictly forbidden to use refrigerant to purge the pipeline for emptying. This method is difficult to completely remove the air and moisture in the system, especially when the system pipeline is long.
1. Before vacuuming, the gas used for maintaining pressure in the system should be discharged clean, subject to the gauge pressure being reduced to 0MPa.
2. After the vacuum reaches -0.1MPa (gauge pressure -1kgf/cm2), close the high and low pressure stop valves and stop the vacuum pump. If the vacuum cannot be maintained, it indicates that the system is leaking, and the system needs to be re-tested for leaks and repaired to qualified.
7.Refrigerant filling: The filling volume of the unit should be calculated strictly according to the nameplate requirements and the length of the connecting pipes between the internal and external units. When filling, an electronic scale should be used to accurately measure the amount of refrigerant poured.
The refrigerant is charged into the liquid pipe side in liquid form, and the electronic scale is observed until the required filling amount. If the system cannot be added to the system without starting up, let the system run at full refrigeration load, and the refrigerant is charged into the gas pipe side in gaseous form, and observe the electronic scale until the required filling volume.
8. Trial operation: restore the compressor electric heating belt, temperature sensor and other electrical components to their original positions. Restore the power and ensure that the unit is well grounded. And jog the compressor to see if it reverses. Start trial operation, listen to whether the compressor and fan have abnormal noise, whether each mode is operating normally, and whether the unit current is within a reasonable range.
