There are four main components that make up the basic refrigeration system of high-precision constant temperature and humidity air conditioners: compressor, evaporator, condenser, and expansion valve. In order to improve the performance of the refrigeration system and achieve better performance, there are usually many auxiliary devices: liquid pipeline solenoid valve, sight glass, liquid pipeline filter dryer, high and low pressure controller, etc.
1. High-precision constant temperature and humidity air conditioner liquid pipeline solenoid    
valve The liquid pipeline solenoid valve is controlled by the main control board in the refrigeration system and is connected in series with the compressor, high-pressure protection switch, and airflow protection switch. When the compressor is shut down, due to the inertia and the thermal properties of Freon, a large amount of Freon enters the evaporator. When the compressor is started again, wet vapor enters the compressor suction port, causing a wet stroke, which is not easy to start. In severe cases, the valve plate is even broken. The setting of the liquid pipeline solenoid valve avoids this situation.
2. High-precision constant temperature and humidity air conditioner sight glass     
The sight glass is located between the refrigeration solenoid valve and the filter dryer in the refrigeration system. As the name suggests, it is used to observe the flow state of the liquid. The amount of bubbles can be used as a reference for the amount of refrigerant injection, and the color of the sight glass can be used to see the water content in the system.
3. Liquid pipeline filter dryer
Usually, the liquid pipeline filter dryer is not removable. The internal molecular sieve structure can remove a small amount of impurities and water in the pipeline, so as to purify the system. Because oxides will appear in the pipeline during welding, and the purity of Freon refrigerants is also different, the Freon refrigerants we use are required to be imported. When the liquid pipeline filter dryer is blocked, the suction pressure will be reduced, and a temperature difference will appear at both ends of the filter. If this happens, the filter needs to be replaced.
4. High-precision constant temperature and humidity air conditioning high and low pressure controller     
In the refrigeration system, the high and low pressure controller is a protective device. High pressure protection is an upper limit protection. When the high pressure reaches the set value, the high pressure controller is disconnected, the compressor contactor coil is powered off, and the compressor stops working to avoid damage to parts under ultra-high pressure. High pressure protection is a manual reset. When the compressor is to be started again, the reset button must be pressed first. Of course, before restarting the compressor, the cause of the high pressure should be checked first, and the machine can only operate normally after it is eliminated. Low pressure protection is a protective device set to prevent the refrigeration system from running under too low pressure. Its settings are divided into high limit and low limit. Its control principle is: when the low voltage cut-off protector is disconnected, it will send a signal to the computer control board, and the compressor will stop and the control board will alarm. The low voltage controller is automatically reset, but it can only be restarted after the alarm is eliminated under the control of the computer board. Therefore, the operator is required to observe the operation of the machine on site and deal with the alarm in time, so as to achieve better protection effect.