In most refrigeration applications, in order to automatically control the flow of fluids in a system, it is necessary to be able to start or stop the flow in the refrigerant circuit. An electrically operated solenoid valve is usually used for this purpose. Its basic function is the same as a manually operated shutoff valve, but it can be positioned in remote locations, and may be conveniently controlled by simple electrical switches. Solenoid valves can be operated by a thermostatic switch (the most common in refrigeration systems), float switches, low pressure switches, high pressure switches or any other device used for making or breaking an electric circuit.
