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What to Do if the High and Low Temperature Test Chamber Can't Keep the Low Temperature?

Ⅰ. Observe the refrigeration compressor of the high and low temperature test chamber


Whether it can be started is very important to the operation of the machine. If the compressor of the high and low temperature test box can be started during operation, it means that the electrical circuit from the main power supply to the compressor of each high and low temperature test box is normal, and the electrical system is also no problem.


When there is no problem with the electrical system of the high and low temperature test chamber, continue to check the refrigeration system. First check the two sets of refrigeration compressors in the high and low temperature test box. If the discharge and suction pressures of the low temperature (R23) compressor are lower than normal, and the suction pressure is evacuated, this indicates that the main refrigeration unit is The amount of refrigerant is obviously insufficient.


Then touch the exhaust and suction pipes of the R23 compressor of the main unit of the high and low temperature test box. If the temperature of the exhaust pipe is not high, the temperature of the suction pipe is not low (no frost). This also explains the lack of R23 refrigerant in the host group.


Ⅱ. Observe the two sets of units in the high and low temperature test chamber


One of the high and low temperature test chamber 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. At the beginning of the temperature maintaining phase, the two groups of units still work at the same time.


When the temperature is initially stabilized, the auxiliary unit will stop working, and the main unit will maintain the temperature drop and stability. If the main engine group R23 leaks, the cooling effect of the main engine group will not be great. Since the two units work at the same time during the cooling process, there is no phenomenon that the temperature is unstable, but only the cooling rate is reduced.


In the temperature maintenance phase, once the auxiliary unit stops working and the main unit has no cooling effect, the air temperature in the high and low temperature test chamber will rise slowly. When the temperature rises to a certain level, the control system will start the auxiliary unit to cool down, and then assist The unit stops working again. Repeatedly, there will be a failure phenomenon that the low temperature cannot be maintained.


So far, it has been confirmed that the cause of the failure of the high and low temperature test chamber is the leakage of refrigerant R23 of the low temperature (R23)-class unit of the main refrigeration unit.


Ⅲ. Check the refrigeration system of the high and low temperature test chamber


Please use a combination of leak detector and soapy water to check where the leak is. If you find that the stem of the hot gas bypass solenoid valve is cracked or cracked, replace the solenoid valve. If you find a leak in other places, use it. Oxygen welding will repair the leaks completely, and then refill the system with fluorine, and the system operation can return to normal.


It can be seen from the above that the analysis and judgment of the failure phenomenon that the high and low temperature test chamber cannot maintain the low temperature is basically from easy to difficult. Understanding the principle and working process of the high and low temperature test chamber is the basis for analyzing and judging failures.


People only deeply understand the working principle and working process of the high and low temperature test chamber, then they can quickly solve the various problems that occur during the operation of the high and low temperature test chamber.

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