case where the b side is pressurized which shifts the flushing valve 300 to the left which allows the flushing of fluid from the low pressure a side through the flushing valve 300 and into the pressure relief valve 310 fig3 c shows the neutral case where the a side and b side are at substantially the same pressure leaving the flushing valve 300 in the center position which allows the flushing of fluid from both the a side and b side through the flushing valve 300 and into the pressure relief valve 310 thus in a powered condition when higher pressure on one side shifts the valve both the open center and closed center flushing valves allow flow from the low pressure side of the hydrostatic loop however in an unpowered condition when pressure is substantially equal on both sides of the valve the open center valve enables flushing from both sides of the hydrostatic loop while the closed center valve stops flow in the hydrostatic loop thus there is always flow bleeding through the open center valve whether the hydrostatic circuit is powered or unpowered the downstream valve 210 in fig2 a 2c and 310 in fig3 a 3c can be used to regulate the amount of flow that can be exhausted from the circuit in a powered condition this type of downstream valve can be used in both a closed center and open center configuration to prevent the flushing of an excessive amount of flow from the circuit fig2 and 3 illustrate the downstream valve as relief valve 210 310 respectively but it can be implemented in a number of different ways the relief valve 210 310 requires enough pressure to overcome a spring.