First, prepare all tools and emergency supplies before operation. Such as ammonia tanks or a certain number of ammonia bottles, scales, connecting pipes, fitter tools, gas masks, rubber gloves and first aid medicines. Then adjust the relevant valves of the system, close the liquid supply valves to the low-pressure equipment and evaporator, and start the compressor to pump the ammonia from the low-pressure system to the condenser and high-pressure reservoir. Place the ammonia bottle on the scale, and use a high-pressure rubber tube (pressure resistance above 3MPa) to connect the empty ammonia bottle to the ammonia discharge pipe of the ammonia refueling station. The connection should be firm. Slightly open the ammonia valve on the ammonia refueling station to check the tightness of the ammonia pipe and joints. Open the pressure reducing valve on the ammonia refueling station to reduce the pressure of the ammonia tank or ammonia bottle, then close the pressure reducing valve and open the ammonia release valve to discharge ammonia into the ammonia bottle or ammonia tank.

            Secondly, the ammonia tank that has let off the ammonia is weighed. Normally, it should not exceed 60% of its capacity. When the required amount is added, close the ammonia bottle valve and the liquid valve on the ammonia refueling station in time, open the pressure reducing valve on the ammonia refueling station, evacuate the liquid in the ammonia pipe, close the pressure reducing valve, and slowly remove the cylinder Connect the tube and replace it with a new bottle. When the ammonia tank reaches the quantity, first close the ammonia tank valve, open the pressure reducing valve on the ammonia refueling station, and after the ammonia liquid in the pipe is drained, close the pressure reducing valve and remove the connecting pipe. If the suction pressure of the refrigeration compressor is too low, the cold storage door can be opened to increase the temperature of the storage and the evaporation of ammonia. The suction pressure of the machine can be increased. The low-pressure system can pump to 0.05MPa (gauge pressure). After stopping, if the pressure rises, it can be restarted to pump down. In order to facilitate the condensation of ammonia, the condensation pressure can be made higher, for example, it can be controlled between 1.3 to 1.4 MPa (gauge pressure).

　　 Finally, the liquid level in the high-pressure reservoir drops below 5%. When the ammonia liquid cannot enter the ammonia cylinder or ammonia tank, and the pressure of the low-pressure system rises below 0MPa (gauge pressure), it can be regarded as the end of the ammonia extraction. The remaining small amount of ammonia can be put in a bucket with water or in a condenser pool.

　　 In addition to the above methods, when ammonia refrigerant cannot be extracted due to the structural characteristics of the compressor (such as semi-closed, fully closed type), another refrigeration compressor must be used to assist in the task of extracting refrigerant.