Heater chiller is a new experimental equipment that can provide low-temperature and high-temperature circulating liquid. Its temperature control range is wide, and the same heat transfer oil can be used to complete temperature control, avoiding the cumbersome procedure of replacing heat transfer oil. The heater chiller can also realize direct cooling from high temperature, so as to complete the temperature conversion faster and reach the temperature required by the experiment. It is widely used in colleges and universities, environmental protection, biochemistry, medical treatment, chemical industry, scientific research and other fields. It is an ideal temperature control equipment in modern medium-sized experiments.
Next, we will analyze and explain some common faults in the use of heater chiller.
1、 Low valve temperature fault: the outlet temperature of expansion valve is an important factor affecting heat exchange. The outlet temperature of expansion valve reflects the evaporation temperature. Generally, the temperature difference between expansion valve and refrigerant liquid is 5 ~ 6 ℃. When the low valve temperature fault occurs, the compressor will shut down and automatically resume operation when the valve temperature rises.
2、 Compressor overheating fault: thermistor is installed inside the motor winding of the compressor, and the resistance value is usually 1K Ω. When the winding temperature is too high, the resistance value will increase rapidly. When it exceeds 141k Ω, the thermal protection module SSM will cut off the operation of the unit and display the overheating fault on the control panel.
3、 Low pressure fault: low pressure fault refers to that the suction pressure of the compressor is too low, resulting in the action of the low pressure protection relay. The low suction pressure indicates that the amount of return air is also small, the refrigeration capacity is insufficient, and it will cause poor heat dissipation of the compressor motor, which is easy to cause motor damage.