Solenoid valve is a valve using electromagnetic force. It is an on/off valve that controls the flow of refrigerant in response to power failure. Solenoid valves can be broadly divided into two categories:
Direct-acting solenoid valve-when the valve coil is energized, the solenoid valve directly opens/closes the valve port.
Servo solenoid valve-when energized or powered off, the valve opens the pilot port, allowing the main port to open gradually depending on the pressure difference between the diaphragm and piston (depending on whether the valve is NC or NO) ,
NC (normally closed) : limit refrigerant flow without power (normally closed) , valve coil power allows refrigerant flow.
No (normally open) : allow refrigerant flow when power is not on (normally open) , valve coil power limit refrigerant flow.
How it works: when the refrigerator temperature rises, the temperature sensing packet pressure rises to the set value, power terminals 1 and 4 connected, thus opening the solenoid valve, allowing refrigerant flow into the evaporator. When the temperature drops, the pressure in the temperature sensing bag drops to the set value. Terminals 1 and 4 are disconnected and subunits 1 and 2 are connected. Solenoid valve power off and closed, thereby limiting the refrigerant flow to the evaporator, so that the temperature of the cold storage room rise.
