The newly built cold storage system should be vacuumized before filling refrigerant. As for the harm of not vacuumizing, we have said many times that the refrigeration encyclopedia public number is not repeated here. First connect the tee gauge to the suction and exhaust Angle valves of the compressor, open the Angle valve, and open the vacuum pump to vacuum. Generally, stop vacuumizing when the temperature reaches -0.1mpa (760mmHg). The vacuumizing time depends on the size of the cold storage and vacuum pump, and the pressure value displayed on the pressure gauge.
Must pay attention! It is strictly forbidden to use the compressor to vacuum, because with the deepening of the vacuum degree in the refrigeration compressor shell, the insulation medium is lost between the exposed binding posts or the windings with tiny damage to the insulation layer. Once the electricity is energized, the motor may be short-circuited and burned in an instant. If the shell leaks, it may cause electric shock.
After vacuumizing, prepare to add refrigerant. We need to understand that the correct amount of refrigerant filling in cold storage is the key factor to determine the operation efficiency of refrigeration system!
For example, insufficient refrigerant filling amount in cold storage will reduce the efficiency of suction pressure and exhaust pressure, especially for the return air cooling compressor may also cause motor overheating; If the amount of refrigerant is too high, the compressor may be damaged due to serious frosting of the evaporator, high condensation pressure, or liquid return of the evaporator. Even if the same refrigeration equipment, because of the internal cold storage volume, evaporation temperature, condensation pressure is different, and different optimal refrigerant filling amount.
In the maintenance of cold storage refrigeration system, in most cases, gaseous or liquid refrigerant can be charged from the low pressure side. When the amount of refrigerant is large, liquid refrigerant can also be charged from the high pressure side. Attention needed! If you charge liquid refrigerant from the low pressure side, be sure to add slowly to avoid liquid strike! If you are afraid of liquid shock, gas can also be filled.
Method of adding refrigerant from the low pressure side:
From the low voltage side filling gas refrigerant operation, low pressure tee first globe spin counterclockwise to the endpoint, then add the fluorine bottles of fluorine pipe joint in the low pressure of the 3-way valve bypass seat, then open the bottle of R22 fluorine cylinder valves, to bypass of the silk of cut-off valve nipple let a little, will add fluoride tube R22 gas out of the air, On hearing a "hissing, hissing" airflow sound at the joint, immediately lock it and refrigerant charging begins.
When the injection amount reaches the specified quality, close the fluorine bottle stop valve, rotate the low-pressure three-way stop valve to the end point counterclockwise, close the bottle valve of R22 fluorine bottle, remove the fluorine pipe, and the fluorine adding work is finished.
