FS-3 – Series Flow Switch

This ultra compact flow switch has been specifically designed for reliable operation in clean post-filtered water. They are made primarily of Noryl® , with all other wetted materials also FDA or NSF compliant. FS-3 switches are instrument quality, yet affordably priced for pure water equipment… from U.V. Lamp switching to Filter Life Monitoring. Also well suited to some chemical applications and a variety of cooling applications: lasers and heat exchangers where clean recirculated water is used.


  • Electronic Equipment: Laser Heads, Welders, Power Supplies, High Speed Spindles, X-Ray Tubes, Semiconductor Equipment
  • Bearings or Gears: Presses, Rotating Equipment, Conveyors, Machine Tools, Robotics
  • Processing & Dispensing Equipment: Water Purifications and Filtering, X-Ray Film Processing, Beverage Dispensing, Chemical Additives, Gas Sampling, Distilling


When the magnetic field of permanent magnet inside the shuttle or piston is moved into the proximity of the reed switch inside the stationary stem, the reed switch contacts “snap” together and closes the electrical circuit. When the magnetic field is moved away from the reed switch, the reed switch contacts move apart and the circuit is opened.

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Flow Rate Settings
Liquids 0.05 GPM to 1.00 GPM
Gases 25 CFH to 12 CFM
Port Size
1/4" Male NPT
Primary Construction Material
Setting Type