Reasons for slow cooling rate of high and low temperature test chamber

1. There is no problem with the electrical system. Continue to check the refrigeration system. First, check whether the discharge and suction pressures of the low-temperature (R23) compressors of the two sets of refrigeration units are lower than the normal values, and whether the suction pressure is in the evacuated state, indicating that the amount of refrigerant in the main refrigeration unit is insufficient.

2. Touching the exhaust pipe and suction pipe of the main engine R23 compressor by hand, it is found that the temperature of the exhaust pipe is not high, and the temperature of the suction pipe is not low (no frost), which also indicates that the main engine R23 refrigerant is insufficient.

3. Observe whether the refrigeration compressor can be started when the test chamber is running, and whether the compressor can be started when the equipment in the high and low temperature test chamber is running, indicating that the circuit from the main power supply to each compressor is normal, and the electrical system is normal.

4. The cause of the failure has not been determined. The cause of the failure is further confirmed in conjunction with the control process of the test chamber. The test chamber has two sets of refrigeration units. One is the main unit and the other is the auxiliary unit. When the cooling rate is high, the two units work at the same time. In the initial period of temperature maintenance, the two units still work at the same time. When the temperature is initially stabilized, the auxiliary machine stops working, and the main machine keeps the temperature stable. If the host R23 leaks, the cooling effect of the host will be poor. During the cooling process, the two units work at the same time, there is no temperature instability, indicating that the cooling rate is reduced. In the heat preservation phase, once the auxiliary unit stops working, the main unit has no cooling effect, and the air in the test chamber will slowly rise. When the temperature rises to a certain level, the control system will start the auxiliary unit to cool down, and then the auxiliary unit will stop working again. If it is repeated, a malfunction will occur.