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FMS-1: Water Flow/Pressure Switch

FMS-1: Water Flow/Pressure Switch
Where to buy: Find a distributor in your region.

This is a pressure-based water flow "switch." The switch is a simple relay control to turn a device on or off if water is flowing or not. The FMS-1 is an included part with the FM-1, but is also sold separately.


  • Can operate a device based on water flow (simple switch: on or off)
  • Convenient telephone jack style connector (modular jack)
  • Durable design
  • Patented design
  • CE marked
  • Included with the FM-1 Filter Monitor (discontinued), but also sold separately.  (We continue to make the FM-2, which includes the FMS-2 Flow Sensor.)  We continue to make the FMS-1 and it can be purchased separately.


  • Tube connection diameter: 1/4" quick-connect fittings
  • Cable length: 93 cm (36.6 in)
  • Dimenions: 19 mm dia. x 64 mm long
  • Cable connector: modular (phone jack style)
  • Minimum activating flow rate: 0.3 liters/minute (0.08 gallons/minute)
  • Maximum pressure: 150 psi
  • Inner material (touches water): polycarbonate
  • Collet material: produced in acetal copolymer with stainless steel teeth
  • Note: Since this switch is pressure-based, when the water is not flowing, there can only be a maximum amount of pressure to allow the contacts to open.
  • Electrical characteristics available upon request (with purchase).