Northern Lihui helps you analyze the reasons for slow cooling

<p>Li Hui helps you analyze the reasons for slow cooling in high and low temperature test chambers.
Many customers encounter slow cooling, inability to lower temperature, and inability to reach -40 degrees Celsius during the use of high and low temperature test chambers.
Below, Northern Li Hui will explain the reasons and solutions for slow cooling in high and low temperature test chambers.
Generally, high and low temperature test chambers will cool down to the corresponding value according to the set time range.
However, due to prolonged equipment use or improper operation, slow cooling in high and low temperature chambers can occur. Now, how to solve this problem and conduct technical discussions.
1. The cause of the malfunction has not been determined. Based on the control process at the testing site, the cause of the malfunction has been further confirmed. 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 high, both sets of units work simultaneously. In the early stage of temperature maintenance, both sets of units still work simultaneously. When the temperature stabilizes initially, the auxiliary unit stops working and is maintained by the main unit. If the host group R23 leaks, the cooling effect of the host group will not be significant.
Due to the simultaneous operation of the two units during the cooling process, there is no phenomenon of unstable temperature, and the indicated cooling rate will decrease. 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 box will slowly rise. When the temperature rises to a certain extent, the control system will start the auxiliary unit to cool down, reducing the temperature to near the set value (-55 degrees), and then the auxiliary unit will stop working again.
This repeated process will result in a failure phenomenon. At this point, it has been confirmed that the cause of the production malfunction is refrigerant R23 leakage in the low-temperature (R23) level unit of the main unit. After conducting a leak check on the refrigeration system using a leak detector combined with soap water, it was found that the valve stem of a hot gas bypass solenoid valve had a crack of about 1cm.
Replace this solenoid valve, refill the system with fluorine, and the system runs normally</ p> <p></p>