FS4-3T Series – General Purpose Liquid Flow Switches

November 01, 2019




For starting or stopping electrically operated equipment such as signal lights, alarms, motors, automatic burners, metering devices and others.

Out of stock



  • In-line configuration eliminates need for a pipe tee
  • ¾” & 1″ NPT process connection – BSPT also available
  • Hardened stainless steel bearings minimize friction
  • Sealed Monel bellows
  • Paddles available for low, medium or high flow
  • Maximum operating pressure: 150 psi (10.5 kg/cm2)
  • Sensitivity adjusting screw makes flow adjustment easy
  • Maximum temperature: 300°F (149°C)
  • Minimum temperature: (fluid or ambient) 32°F (0°C)
  • Switch: SPDT 125 VA at 120 or 240vac, 50 or 60 cycles snap switch


McDonnell & Miller FS4-3T