Customers often encounter constant temperature and humidity chamber is not cooling the situation, so today on this issue together to study and explore the next:
1. Because it is the temperature can not hold to observe the refrigeration compressor in the process of running the test chamber can start, the compressor in the environmental test equipment can be started during the operation, that from the main power supply to the compressor electrical lines normal, electrical There is no problem with the system.
2. There is no problem with the electrical system, continue to check the refrigeration system. First, the exhaust and suction pressure of the low temperature (R23) class compressor of the two groups of refrigerating units are lower than the normal value, and the suction pressure is evacuated, indicating that the refrigerant quantity of the main cooling unit is insufficient.
3. Touch the exhaust and suction lines of the R23 compressor of the main unit by hand and find that the temperature of the exhaust line is not high and the temperature of the suction line is not low (unfrozen), which also indicates that the main unit The R23 refrigerant is lacking.
1. Failure to determine the cause of the failure, combined with the control process of the test chamber to further confirm the cause of the malfunction, the test chamber has two sets of refrigeration units.
2. One for the main unit, the other for the auxiliary unit, the cooling rate is large, the two groups of units at the same time, in the early stage of temperature holding, the two groups still work at the same time. To stabilize the temperature initially, the auxiliary unit to stop working, by the host group to maintain the stability of the temperature. If the host group R23 leak, will make the cooling effect of the host group is not large, due to cooling process, the two units at the same time work, so there is no stable temperature of the phenomenon, and instructions to reduce the cooling rate. In the temperature holding stage, once the auxiliary unit to stop working, the host group and no cooling effect, the air inside the chamber will slowly rise, when the temperature rises to a certain extent, the control system will start the auxiliary unit to cool, the temperature dropped to Set value (-55 ℃) near, and then auxiliary units and stop working, so repeated, the fault phenomenon.
At this point, the cause of the production failure has been confirmed because the refrigerant R23 of the low temperature (R23) class unit of the main unit leaks. The leak detection system, with a leak detector and soapy water combined method of inspection and found a hot air bypass valve stem valve split about 1cm of the slit. Replace the solenoid valve, re-fill the system, the system is running normally. As can be seen above, the analysis and judgment of the fault phenomenon is basically easy to difficult, first "outside" after "in", the first "electrical" after the "cooling" of the context of analysis and judgment, familiar and Understanding the principle and working process of the test chamber is the basis for analyzing the fault judgment fault.