St-5 Flow Switch



  • Mounting Position: Vertical only
  • Magnet Configuration: Free floating
  • Pressure, Minimum: 75 PSI
  • Pressure, Maximum: 3600 PSI
  • Flow Rate, Minimum: 1.0 GPM
  • Flow Rate, Maximum: 8.0 GPM
  • Inlet: 3/8″ FPT
  • Outlet: 3/8″ FPT
  • Cord/Lead Length: 47 inches


  • Lead #1 to Line/Power
  • Lead #2 to Load
  • Yellow with green tracer to Ground

Reed Switch Adjustment: depending on the system flow, it is normal for the magnet position to vary. This variance may require adjustment of the reed switch upon initial installation, especially at lower flow rates. If the switch fails to close upon initial flow, simply loosen the adjustment screw and position the switch so it properly opens/closes according to flow conditions.

SKU: 1565 Category:


The ST-5 is a “normally open” flow switch, designed to be mounted in a high-pressure water line. Inside the housing is a floating magnet which is aligned parallel with a reed switch. When the water flow is initiated, usually by pulling the spray gun trigger, the water flow forces the magnet to move forward. Once in the correct position, the magnet pulls the thin reeds together, closing the circuit and allowing electrical continuity. When water flow ceases, usually when the trigger is released, gravity returns the magnet to its original position. the reeds then pull apart and open the circuit, stopping electrical continuity.

Advantages of flow switches:

  • Mounts further downstream in the pumping system than traditional vacuum switches, thereby minimizing potential leak points that can cause vacuum switches to close.
  • Vacuum switches use rubber diaphragms that often rupture and cause vacuum leaks to the pump
  • Flow switches operate at a variety of pressures
  • Flow switches eliminate the need to restrict water flow to the pump, thereby prolonging pump life
  • the reed switch is encased in a protective glass capsule with a sealed nitrogen atmosphere that eliminates exposure to corrosive cleaning chemicals

Additional information

Weight1.02 lbs
Dimensions4.5 × 5.75 × 1.75 in


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