For newly installed systems,refrigerant can be added from the high-pressure side,and the operation method is as follows:
　　1.Open the cooling water system for the condenser and maintain the valves in the system in the state they were in during the vacuum test.
　　2.14mm to the west×Connect the steel cylinder containing refrigerant with a 2mm seamless steel pipe(red copper pipe when filling with Freon).The bottle mouth is tilted downward and the steel cylinder is at a 30°angle to the ground,or the tail of the steel cylinder is raised by about 200 to 300 mm.
　　3.Open the charging valve.When a certain pressure is reached in the system(0.1-0.2MPa for ammonia system and 0.2-0.3MPa for Freon system),suspend refrigerant filling,and then check the sealing condition of the system at each connection and welding point.If there is no leakage,continue filling with refrigerant.
　　Turn off the power supply and unplug it.
　　4.Close the outlet valve on the reservoir and continue to charge refrigerant.When the cylinder pressure and the pressure in the reservoir reach a balance,open the outlet valve on the reservoir.
　　5.Start the refrigerator,put the refrigeration device into operation,and continue to charge refrigerant.When there is white frost on the lower part of the cylinder,it indicates that the liquid refrigerant in the cylinder has nearly been charged.At this time,the cylinder valve and charging valve can be closed,and the cylinder can be replaced to continue charging.
　　6.Unless the external temperature is very low,it is generally not necessary to pour hot water on the cylinder to increase the pressure inside the cylinder when filling the refrigerant,because it is not safe to do so.If it is necessary to accelerate the filling speed,the temperature of hot water should not exceed 50℃,and other methods of heating the cylinder are strictly prohibited.
　　7.When filling with Freon,a drying filter must be installed on the special connecting pipe to reduce the possibility of moisture entering the system.When using high-pressure section filling,do not start the compressor,and note that the exhaust valve must not leak,otherwise liquid hammer may occur.
　　8.When the refrigerant charge reaches 90%of the charge amount,the charging operation can be temporarily stopped and a trial run of the system can be conducted to check whether the system dose has met the operational requirements,to avoid unnecessary trouble caused by excessive charge.For old refrigeration systems,when refrigerant needs to be replenished,it should be charged from the low pressure side.