1. Check whether the door is closed.
2. The room temperature is too high.
1) Room temperature too high, find ways to reduce the room temperature, such as installing air conditioning in the house or opening the lower baffle and blowing with a fan, so as to achieve the cooling effect.
2) Because the temperature can not be maintained, it is observed whether the refrigeration compressor can start during the operation of the test Chamber and the compressor can start during the operation of the environmental test equipment. It shows that the electrical circuits from the main power supply to the compressors are normal, and there are no problems in the electrical system.
3. There is too much dust in the condenser. Clean up the dust in the condenser and blow it clean.
4. The fan does not rotate; (Observe whether the fan can start during the operation of the test Chamber , such as the fan can start during the operation of the test Chamber , indicating that the fan is normal.)
5. Refrigeration system;
1) Check the refrigeration system. First, check that the exhaust and suction pressure of two groups of low temperature (R23) compressors are lower than the normal value, and the suction pressure is empty, indicating that the refrigeration dose of the main refrigeration unit is insufficient.
2) Touch the exhaust and suction pipeline of the R23 compressor of the main engine group by hand, and find that the temperature of the exhaust pipeline is not high, and the temperature of the suction pipeline is not low (no frost), which also shows that the R23 refrigerant of the main engine group is insufficient.
6. Heavy load;
1) Check whether the test workpiece is live test, and measure the heat generated by the workpiece during live test.
2) If the calorific value is less than 300 W, it has no effect on the test Chamber , but the excessive calorific value will slow down the temperature in the Chamber and make it impossible to reach the instrument setting or not to refrigerate.