The reason for the slow cooling of the high and low temperature test chamber

In the process of using the high and low temperature test chamber, many customers encounter the slow cooling of the high and low temperature test chamber, the temperature does not drop, the temperature cannot reach -40 degrees, etc. 

Under normal circumstances, the high and low temperature test chamber will be cooled to the corresponding value according to the set time range, but due to the long use of the equipment or improper operation, it will cause the high and low temperature chamber to cool down slowly, now how to solve this one problems, and conduct technical discussions.

1. The cause of the failure is not determined, and the cause of the failure is further confirmed in combination with the control process of the test site. The high and low temperature test chamber has two sets of refrigeration units.

2. One is the main unit and the other is the auxiliary unit. When the cooling rate is large, the two groups of units work at the same time. In the early stage of temperature maintenance, the two groups of units still work at the same time. When the temperature is initially stabilized, the auxiliary unit stops working, and the main unit maintains the temperature stability. If the R23 of the main unit leaks, the cooling effect of the main unit will not be large. Since the two units work at the same time during the cooling process, there is no phenomenon that the temperature cannot be stabilized, and the indicated cooling rate decreases. In the temperature maintenance stage, once the auxiliary unit stops working and the main unit has no cooling effect, the air in the high and low temperature test chamber will slowly rise. When the temperature rises to a certain level, the control system will start the auxiliary unit to cool down. Lower the temperature to near the set value (-55 degrees), and then the auxiliary unit stops working again, and so on, there will be failures. So far, it has been confirmed that the cause of the production failure is the refrigerant R23 leakage of the low temperature (R23) level unit of the main unit. The refrigeration system was checked for leaks, and a leak detector was used in combination with soapy water. Replace the solenoid valve, recharge the system with fluorine, and the system runs normally.