Solution for constant temperature and humidity test chamber failures

Troubleshooting constant temperature and humidity in the test chamber
First look to the constant temperature Whether the constant humidity test chamber has been operated at low temperature for a long time. When the programmable constant temperature constant humidity test chamber completes the low temperature operation, the evaporator will freeze. It is best to carry out a drying treatment at 60 °C for about 30 minutes before opening the chamber door. , At this time, the problem of not cooling the constant temperature and humidity box can be solved. hdtTextile Testing Instruments, Testing Equipment Manufacturer

Constant temperature and humidity test chamber Error solving constant temperature and humidity box Electrical appliances, whether the circuit norworks. Because the temperature of the constant temperature and humidity chamber cannot be maintained, observe whether the refrigeration compressor can be started during the operation of the test chamber, and whether the compressor can be started during the operation of the environmental testing equipment machine is normal, and there is no problem with the electrical system. hdtTextile Testing Instruments, Testing Equipment Manufacturer

There is no problem with the electrical system, then check the cooling system. First, check whether the exhaust and suction pressure of the low-temperature compressors (R23) of the two groups of refrigeration units are lower than normal and the suction pressure is in the evacuation state, which indicates that the refrigerant amount of the main refrigeration unit is insufficient.
Check whether the refrigerant is missing in the constant temperature and humidity box, touch the exhaust and suction pipes of the R23 compressor of the main unit, and find that the temperature of the exhaust pipe is nott is high and the temperature of the suction line is not low (there is no frost), the Farui instrument will tell you that the R23 refrigerant of the main unit is missing. hdtTextile Testing Instruments, Testing Equipment Manufacturer

The reasons for the analysis are as follows:
1. The cause of the failure of the constant temperature and humidity chamber was not determined, and the cause of the failure was further confirmed in combination with the control process of the test chamber. The test chamber has two sets of cooling units.
2. One is the main unit and the other is the auxiliary unit. When the cooling rate is large, the two sets of units work at the same time. At the beginning of the temperature maintenance phase, the two units are switched off and the units are still working at the same time. When the temperature stabilizes initially, the auxiliary unit will stop working and the main unit will maintain temperature stability. When the R23 of the main unit leaks, the cooling effect is the mainunit not large Because the two units work at the same time during the cooling process, there is no phenomenon that the temperature cannot be stabilized and the cooling rate of the indicator is reduced. Shanghai Farui Instruments informs you that in the temperature maintenance phase, once the auxiliary unit stops working and the main unit has no cooling effect, the air in the test chamber will slowly rise. When the temperature rises to a certain level, the control system will start the Auxiliary unit to cool down, the temperature drops to about the set value (-55 °C), and then the auxiliary unit stops working, and so on, and breakdowns occur. hdtTextile Testing Instruments, Testing Equipment Manufacturer

So far, it has been confirmed that the cause of the production failure of the constant temperature and humidity test chamber is the low temperature of the main unit (R23) The R23 refrigerant of the level unit is leaking. Look for leaks in the cooling system, check with a comboation of leak detector and soapy water, and notice that the valve stem of a hot gas bypass solenoid valve has a crack with a slit of about 1 cm. Replace the solenoid valve, fill the system with fluorine and the system will work normally. Farui Instruments informs you that, as can be seen from the above, the analysis and assessment of the error phenomenon is basically easy to difficult, first analyzing “outside” and then “inside”, first “electrical” and then “cold” context and judgement, knowledge and understanding of the principle and mode of operation of the test box are the basis for error analysis and error assessment. hdtTextile Testing Instruments, Testing Equipment Manufacturer