Automatic Shut-Off Valve, 4 Way 1/8" Female NPT

S2000W ASO ValvesS2000B
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Part Number: S2000W
Alt. Part Number: S2000B
MSRP: $20.82
Price: $14.87 

The dual diaphragm design of FLOWMATICS's WQA validated valves provide automatic shut-off to supply line when storage tank reaches 65% of inlet pressure, saving thousands of gallons of water per year. Valves are made using FDA grade and NSF certified materials.  Available in Black (S2000B) or White (S2000W), we reserve the right to substitute colors.

Port Connection are 1/8" Female NPT, fittings not included. 

Here's how it works: The valve automatically shuts off production when the tank pressure reaches approximately 65% of the incoming line pressure to indicate the tank is full. This device saves thousands of gallons of water. RO Systems without an ASO valve continually send Rinse water to the drain even when the tank is full.


  1. Insert the tube feeding the membrane inlet into the ASO IN/OUT fittings:
    • Insert the tube from the PREFILTER Outlet into the "IN" fitting .
    • Insert the opposite tube end that feeds the Membrane INLET into the "OUT" fitting . NOTE: The "IN & OUT" markings are on the screw side of the valve - THIS IS THE HIGH PRESSURE FEED SIDE.
  2. Insert the tube feeding the tank from the Product Water port of the membrane housing:
    • Locate the Product Water outlet from the membrane housing (on the end w/ 2 ports: center is Product water, side port is Rinse/Drain).
    • Insert the Product water tube from the membrane housing into either "Tank" fitting of the valve (ie Low Pressure side).
    • Insert the opposite tube end that feeds the Tank into the other "Tank" fitting of the valve.
NSF certified
Automatic Shut-off Valve
Operating Condition
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