Firstly, observe the heightLow temperature laboratoryCan the refrigeration compressor be started during the operation of the high and low temperature test chamber? If the compressors in both high and low temperature chambers can be started during operation, it indicates that the electrical circuits from the main power supply to each high and low temperature chamber compressor are normal, and there are no problems with the electrical system.

　　

whenHigh and low temperature laboratoryWhen there are no issues with the electrical system, continue to check the refrigeration system. Firstly, check the two sets of refrigeration compressor units in the high and low temperature boxes. If the exhaust and suction pressures of the low-temperature compressor are both lower than normal, and the suction pressure is in an evacuated state, it indicates that the refrigerant amount of the main refrigeration unit is significantly insufficient. Then touch the exhaust and suction pipelines of the R23 compressor in the high and low temperature box with your hand. If you find that the temperature of the exhaust pipeline is not high and the temperature of the suction pipeline is not low (without frosting), it also indicates a lack of R23 refrigerant in the main unit.

　　

One main unit and the other auxiliary unit in the high and low temperature laboratory work simultaneously when the cooling rate is high. In the early stage of temperature maintenance, the two units still work simultaneously. Once the temperature stabilizes, the auxiliary unit will stop working and the main unit will maintain the cooling and stability of the temperature. 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 phase, once the auxiliary unit stops working and the main unit has no cooling effect, the air temperature inside the high and low temperature test box will slowly rise. When the temperature rises to a certain level, the control system will start the auxiliary unit again to cool down, and then the auxiliary unit stops working again. This repeated process will result in a fault phenomenon where the low temperature cannot be maintained.

　　

At this point, it has been confirmed that the cause of the malfunction in the high and low temperature laboratory is refrigerant R23 leakage from the low temperature (R23) stage unit of the main refrigeration unit.

　　

Repair method for high and low temperature laboratory: Check for leaks in the refrigeration system of the high and low temperature test chamber. Use a leak detector combined with soap water to identify the leak point. If it is found that the valve stem of the hot gas bypass solenoid valve is cracked with a fine seam, replace the solenoid valve. If leaks are found in other areas, use oxygen welding to repair the leak, and then refill the system with fluorine to restore normal operation.

　　

For the above analysis, it isHigh and low temperature laboratoryThe analysis and judgment of the fault phenomenon of inability to maintain low temperature is basically from easy to difficult, starting from the outside and then the inside, starting with electrical and then air conditioning. Familiarity and understanding of the principles and working processes of high and low temperature laboratories are the basis for analyzing and judging faults.