Application of Electric Two (Three) Way Valve in Air Handling Unit Control System

System control: The system variable electric two (three) way valve shown in the figure is used in conjunction with various drivers in the control system of a two pipe cold/hot water dual purpose air handling unit. This system is mainly composed of a proportional plus integral temperature controller, a temperature sensor installed in the return air duct, an electric regulating valve, and drivers. The function of the controller is to compare the temperature detected by the temperature sensor with the temperature set by the controller, According to the comparison results, the corresponding voltage signal is output to control the action of the electric valve to maintain the air supply temperature within the required range. The conversion switch of the system is for switching between winter and summer.

Summer cooling: When the room temperature detected by the temperature sensor is higher than the temperature set by the temperature controller, the electric control valve acts and the flow increases; Conversely, when the room temperature detected by the temperature sensor is lower than the temperature set by the temperature controller, the valve acts and the flow decreases.

Winter heating: When the room temperature detected by the temperature sensor is lower than the temperature set by the temperature controller, the electric control valve acts to increase the flow rate; On the contrary, when the indoor temperature detected by the temperature sensor is higher than the temperature set by the temperature controller, the valve acts, and the flow rate decreases. The R contact group in the figure can be interlocked with the fan. When the fan starts, the fresh air damper opens, and the power supply to the temperature controller is turned on, and the entire system is controlled; When the power supply of the fan is cut off, the fan stops rotating and the fresh air damper is closed.