When using the high and low temperature test chamber, it is found that it cannot be removed at low temperatures. In this case, the following aspects need to be checked:

1. Firstly, check if the compressor has started. If it has not started, you can check upwards along the compressor power supply and solve the problem wherever you find it.

2. If the compressor has already started but still has no effect, you can use a clamp ammeter to measure whether the current of each phase of the compressor is the same. If the difference is not significant, it indicates that the compressor is not a problem. If the difference is too large, the compressor may be broken and needs to be replaced.

3. If there are no problems with the above two checks, then it is necessary to check whether there is refrigerant leakage in the refrigeration system. Generally, this can be observed through the pressure gauge on the equipment itself. If the pressure gauge does not change during the start and stop states of the compressor, it indicates that there is a leakage in the refrigeration system of the compressor. At this time, leak detection and repair are needed. During leak detection, nitrogen can be filled into the system, with a nitrogen filling amount generally between 1.5Mpa and 2.5Mpa. After filling the leak point, a vacuum pump should be used to evacuate it, and then refrigerant can be filled.

4. If there are no problems with the above three items, it is time to check the heating system. It is possible that the solid-state relay controlling the heater has malfunctioned, and its continuous heating will offset the energy generated by cooling, resulting in the inability to lower the low temperature. When checking, an electric meter can be used to measure whether the output terminal of the solid-state relay has electricity. If there is electricity, it indicates that the solid-state relay is broken and can be replaced.

5. If all the above checks are normal, it is necessary to check the temperature sensor and controller. You can use a relatively accurate thermometer or mercury thermometer to compare the displayed value on the controller with the value on the thermometer or mercury thermometer at room temperature when the equipment is not started. If the deviation is large, it indicates that the sensor has a problem. If it is similar, it indicates that the controller has a fault.

In short, the above items are fundamentally common, and of course, other non major faults such as sealing can also be checked and improved.

Submitted by the After sales Service Department of Shanghai Jinyou Experimental Equipment Co., Ltd

Prepared by the Technical Department of Shanghai Jinyou Experimental Equipment Co., Ltd