A variable flow valve assembly is disclosed, and includes a main body, a piston, a position sensor, a controller, a solenoid, and a cover. The main body defines a chamber, an inlet port, an outlet port, and a wall located between the inlet port and the outlet port. The wall defines a metering orifice for selectively allowing a medium to flow from the inlet port to the outlet port. The chamber of the main body includes a pressurized chamber. The piston is moveable within the chamber of the main body in a plurality of partially open positions to vary the amount of medium flowing through the modulation orifice. The piston separates the pressurized chamber from the inlet port. The position sensor determines the position of the piston within the chamber of the main body, and the controller is in signal communication with the position sensor.