A flow control valve having a body with an inlet port, an outlet port and an access opening. The body has a cavity connecting with the access opening and communicating between the inlet and outlet ports. A single pair of discs with orifices is located within the cavity. One disc is secured to the bonnet which extends into the cavity and the other is attached to a rotatable turning fork which rotates to change the alignment of the disc orifices thereby controlling flow to the outlet port. The bonnet and the turning fork have openings which allow fluid to flow from the inlet port to the discs. The bonnet attaches over the access opening and secures the turning fork, the discs, a wear insert and a lower seat within the cavity. An o-ring holds the valve assembly together as it is installed and removed from the valve body.