General Purpose Liquid Flow Switch, Series FS250

McDonnell & Miller : Flow Switches :

McDonnell & Miller announces new General-Purpose, Liquid Flow Switches, the Series FS250 – FS251 (NEMA1 version), and FS254 (NEMA4 version). These flow switches incorporate key changes to address customer expressed needs of greater reliability and lower flow sensing capabilities in a general purpose flow switch.

Features and Benefits

  • Common switching mechanism for both the FS251 and FS254
  • Measured flow-rate sensing of 5.8 gpm in 1” pipe (2.2 fps) in horizontal pipe installations, which is 18% lower than measured flow of comparable general purpose flow switches from major competitors. (Refer to submittal MM-627 for flow rates.)
  • 1-inch NPTM brass pipe connection
  • 1”, 2”, 3” and 6” Stainless steel paddles standard
  • Section IV boiler ratings of 250º F and 160 psig
  • No lead construction
  • Housing materials:
  • – FS251 – stamped sheet steel base with glass reinforced
  • polycarbonate cover
  • – FS254 – Cast aluminum base and cover


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