Flow control valves may be positioned downstream of water meters to increase pressure and compress entrained water vapour passing through the meters. However, turbulence within such valves can cause the valve's head to move radially, bending a shaft within the valve which may break. Accordingly, there is provided a flow control valve comprising: a housing having a flow passage; a valve seat defined within the flow passage; a valve head moveable to a closed position to engage the valve seat and seal the flow passage; a shaft secured to the valve head; a support slidingly mounting the shaft within the housing; a spring biasing the valve head to the closed position and configured to maintain the valve head in the closed position until a predetermined pressure is applied; and a guide assembly extending along at least a portion of the flow passage to constrain radial movement of the valve head.