1. Check whether the alarm protection function is normal, whether the refrigeration compressor of the constant temperature test chamber is started and running, check the air pressure gauge of the refrigeration compressor, and check whether the internal refrigerant is leaking; Only then can the constant temperature and humidity test chamber be lowered normally;

2. Check whether the cooling fan is operating normally, check whether the dust in the air inlet is too thick, check whether the internal circulation fan of the housing is operating normally, check the DC contactor of the refrigeration compressor and its overheating Check whether the flow protector is damaged; check whether the relay in the pipeline is turned on, check whether the intermediate relay of the heating system is damaged, and affect the cooling system;

3. Because part of the constant temperature chamber will adopt the cascade refrigeration method, if one of the refrigeration compressors cannot work normally, it will also cause the equipment to fail to normal down to check the automatic control system of the refrigeration compressor Whether it is working normally, check whether there is any sound in the operation of the compressor, or there is an abnormal working sound, these may cause failure to lower the position.