Step1: check if the refrigeration compressor of the high and low temperature test chamber in the process of the test box can start. If it can start, it supplies the electrical circuit is normalfrom the main power supply to the test box compressor, and electrical system is no problem.
Step 2: check the refrigeration system and check the refrigeration system for the compressor unit.When the refrigerating dose of the main refrigeration unit is insufficient, the reason for it must be in the normal value of the exhaust and inspiratory pressure of the compressor at the low temperature stage, and the suction pressure is to be evacuated.Test chamber R23 compressor suction pipe and the exhaust of main unit, if discover the exhaust temperature is not high, the temperature of the suction piping is not low (frost), it is also shows that the lack of the refrigerant compressor
Step 3: high and low temperature test chambers are divided into main units and auxiliary units. During the initial and cooling rate of the temperature maintenance phase, the two sets of units are working simultaneously.But in the stage of the temperature to maintain, auxiliary units once stop working, and the main unit without refrigeration effect, it can lead to test the air temperature in the cabinet slowly rising, while rising to a certain extent, the control system will restart auxiliary machine to cool, then auxiliary machine stops working again, repeated like this will lead to appear the phenomenon of low temperature keep not to live.