Precautions for overhaul of refrigeration system of refrigerators using R600a refrigerant

1. Maintenance site:

Smoking is strictly prohibited; equipped with fire-fighting equipment, well ventilated; equipped with leak detector/R600a sensor (if conditions permit); R600a special exhaust equipment should be provided, which must be turned on when working , Because R600a is heavier than air, the exhaust vent must be located close to the ground; ventilation equipment and electrical appliances in the site should be explosion-proof; there should be no grooves and pits in the site; the site should have fire protection signs.

2. Maintenance equipment:

The R600a storage tank should be placed separately in an environment of -10~50°C, well ventilated, and a warning label should be attached; the leak detection equipment must ensure that it can It is used for R600a refrigerant; R600a refrigerator must use special explosion-proof vacuum pump and charging equipment. Because of the different lubricating oil (R134a refrigerator uses lipid oil, R600a refrigerator uses mineral oil), it is not allowed to mix with R134a refrigerator maintenance equipment; The charge volume of R600a refrigerator is only 40-50% of that of R134a refrigerator, so the vacuuming and filling equipment of refrigerator should ensure certain accuracy, the vacuum degree should be less than 10pa, and the filling volume deviation should be less than 1g; R600a maintenance tools and refrigeration The maintenance tools in contact with the agent should be stored and used separately, and should not be mixed with the maintenance tools of the R134a refrigerator.

3. Maintenance technology:

It is not allowed to open the refrigeration system in the user’s home; the type of refrigerant should be determined from the compressor’s nameplate before the refrigerator is repaired; because R600a refrigerant affects lubricating oil In addition to its strong solubility, coupled with its low pressure, the low pressure side of the refrigerator is usually negative when the refrigerator is working. Therefore, before repairing and welding the refrigeration system, ensure that the R600a in the system is discharged cleanly. Usually, the high and low pressure process pipes should be opened first to discharge. Then use the R600a special vacuum pump to evacuate the high and low pressure sides, while gently shaking the compressor by hand; if the compressor is replaced, the charge volume is the nominal value on the refrigerator parameter plate, if the compressor is not replaced, the charge volume is the nominal value 90% of the value; no open flame should be used for the system seal, ultrasonic welding or lock ring can be used; the nozzle of the replaced compressor must be sealed; because the R600a refrigerator is working, the low pressure side is negative pressure, so the refrigerator should be stopped during leak detection ; The temperature controller and light switch of the refrigerator compartment of R600a refrigerator are not in contact with the refrigerant, and can be used in common with R134a refrigerator; the desiccant used in R600a refrigerator is the same as that in 134a refrigerator, and the drying filter can be used in common (only unused new drying filter The solenoid valve of the R600a dual-capillary refrigerator must be explosion-proof and cannot be mixed with the R134a refrigerator.