Pressure reducing & surge control valve automatically reduces a higher inlet pressure to a steady lower downstream pressure regardless of flow rate and inlet pressure fluctuations. Pilot valve enables the main valve to close quickly to prevent downstream surges. ADDITIONAL RELIEF/SUSTAINING FUNCTION-400 401-02 pressure sustaining/differential pressure/check 402-pressure sustaining solenoid on/off valve 403-surge anticipator relief/remote sense Adjustment range : 0-150 psig