A flow regulator includes a body with an aperture into which an inlet and an outlet open. A pin has a bore extending therein and communicating with the outlet. A first aperture, a second aperture and a bypass orifice are spaced longitudinally along the pin and extend there through opening into the bore. A valve member is slideably located around the pin and is biased by a spring into a first position along the pin in which the valve member closes the first aperture while opening the second aperture. When a pressure differential between the inlet and outlet exceeds a first level, the valve member moves away from the first position and begins covering the second aperture. Thereafter continuing increase of the pressure differential above a greater second level results in the valve member moving into a second position at which both the first and second apertures are closed. However in the second position, a secondary flow path exists between the inlet and the outlet through the bypass orifice. Further increase of the pressure differential significantly above the second level causes the valve member to move into a pressure relief position in which the first aperture is open while the second aperture remains closed.