Starting at $95.00
  • Usually ships in 2-3 weeks



  • Flow Rate Settings: 0.25 GPM to 5.0 GPM
  • Port Size: 3/4" NPT
  • Primary Construction Material: Polypropylene
  • Maximum Operating Pressure: 100 PSIG @ 70°F; 50 PSIG @ 180°F; 40 PSIG @ +212°F
  • Operating Temperature: 0° to 212°F
  • Set Point Accuracy: ± 20%
  • Set Point Differential: ± 20% Maximum
  • Switch: SPST, N.O. Pilot Duty 20 VA, 120-240 VAC or VDC
  • J-Box with 5A Relay Available


The Gems FS-500 series flow switches offer low cost flow monitoring with a variety of switch actuation points and low pressure drop. All wetted parts of the FS-500 series are polypropylene or stainless steel, making this switch ideal for a wide range of chemical and temperature requirements. The materials are also NSF or FDA approved for potable water treatment applications including chlorinators, purifiers and heaters. The FS-500 is ideal for equipment cooling including welders, lasers, etc. A J-box version with a 5 amp relay is also available for direct control of higher electrical loads, such as chlorinator pumps

The FS-500 series has a 3/4" NPT process connection and flow settings ranging from 0.25 to 5.0 gpm. The simple and reliable design is suitable for operating temperatures from 0 to 212°F and line pressures up to 100 psig at 70°F. The FS-500 series utilizes a SPST switch.

Applications for the Gems FS-500 Series flow switch:

  • Protect Bearings or Gears: oil separators, fuel systems, pumps, compressors, presses
  • Electronics or Machinery: heat exchangers, semiconductor manufacturing equipment, induction furnaces, radio transmitters
  • Process Systems: water filtration and reverse osmosis, chlorinators, de-icers, sterilizers, evaporators


This product can be used in the following applications: