A pressure regulator comprising: a valve body that defines a fluid flow path between an inlet and an outlet ; an orifice assembly that is positioned along the fluid flow path, the orifice assembly including a first side and a second side opposite the first side; a stem ; a lever configured to control movement of the stem when engaged with the stem, as driven by movement of a diaphragm ; a primary control member that is coupled to the stem, wherein, in a first mode of operation of the pressure regulator, the primary control member is moveable relative to the first side of the orifice assembly , by movement of the stem , between: a first position in which the primary control member contacts the first side of the orifice assembly to restrict fluid flow along the fluid flow path, and a second position in which the primary control member is separated from the first side of the orifice assembly ; and a secondary control member that is coupled to the stem and is movable relative to the second side of the orifice assembly , by movement of the stem , wherein: in the first mode of operation of the pressure regulator, the secondary control member is moveable between a first position and a second position, in each of which the secondary control member is separated from the second side of the orifice assembly ; and in a second mode of operation of the pressure regulator, the secondary control member is movable to a third position in which the secondary control member contacts the second side of the orifice assembly to restrict fluid flow along the fluid flow path. a valve body that defines a fluid flow path between an inlet and an outlet ; an orifice assembly that is positioned along the fluid flow path, the orifice assembly including a first side and a second side opposite the first side; a stem ; a lever configured to control movement of the stem when engaged with the stem, as driven by movement of a diaphragm ; a primary control member that is coupled to the stem, wherein, in a first mode of operation of the pressure regulator, the primary control member is moveable relative to the first side of the orifice assembly , by movement of the stem , between: a first position in which the primary control member contacts the first side of the orifice assembly to restrict fluid flow along the fluid flow path, and a second position in which the primary control member is separated from the first side of the orifice assembly ; and a secondary control member that is coupled to the stem and is movable relative to the second side of the orifice assembly , by movement of the stem , wherein: in the first mode of operation of the pressure regulator, the secondary control member is moveable between a first position and a second position, in each of which the secondary control member is separated from the second side of the orifice assembly ; and in a second mode of operation of the pressure regulator, the secondary control member is movable to a third position in which the secondary control member contacts the second side of the orifice assembly to restrict fluid flow along the fluid flow path. in the first mode of operation of the pressure regulator, the secondary control member is moveable between a first position and a second position, in each of which the secondary control member is separated from the second side of the orifice assembly ; and in a second mode of operation of the pressure regulator, the secondary control member is movable to a third position in which the secondary control member contacts the second side of the orifice assembly to restrict fluid flow along the fluid flow path. <EOS>