APG FS-400 Series Stainless Steel Vertical Float Switch

APG FS-400 Series Stainless Steel Vertical Float Switches are durable float switches with CSA and NSF certifications and a wide range of applications. Their compact size — less than 3.5” from top of threads to end of stem — all stainless steel wetted materials, and user-reversible switch orientation, make them an easy choice for OEM, water and wastewater, and chemical applications. Compact, durable, easy to use.

With all stainless steel wetted materials, operating temperatures up to 500° F, and a 100 W switch, the series FS-400 float switch fits a wide range of applications in two standard configurations.

From the top of the mounting threads, to the bottom of the stem, the FS-400 is less than 3.5″ long, and the float is just over 2″ wide.

Temperature Ranges

The FS-400-S has an operating temperature range of -40° to 368° F (-40° to 187° C), and the FS-400-HT extends that range to -40° to 500° F (-40° to 260° C)!


FS-400-S switches carry CSA Explosion Proof certifications, while FS-400-HT models are certified for General Use. All FS-400 switches are NSF 169 certified.

User Reversible Operation

FS-400 float switches come standard with Normally Open operation. The e-clip at the bottom of the stem is easily removed to change to orientation of the float, changing the switch operation to Normally Closed.

APG FS-400 Series Features

  • Compact size • Reliability/long switch life
  • Shock resistive construction
  • Can be used in a wide range of liquids
  • Operating temperatures up to 500° F (260° C)
  • Switch rated for 100 W • NSF 169 certified
  • CSA Explosion Proof (Standard Temp) and General Use (High Temp)


  • C I, D 1 Hazardous Locations
  • Food / Beverage
  • Chemical
  • Water / Wastewater

APG FS-400 Series Specification

Switch Points 1 NO/NC
Customer Reversible
Specific Gravity Minimum 0.6
Pressure Rating 200 psi / 13.8 bar (Standard)
500 psi / 34.5 bar (High Temperature)
Normally Open Actuation 0.220″ ± 0.015″
5.59 mm ± 0.38 mm
Normally Closed Actuation 0.160″ ± 0.015″
4.06 mm ± 0.38 mm
Hysteresis 0.070″ ± 0.010″
1.78 mm ± 0.25 mm
Switch Rating 100 W (resistive load only)
Max Current (AC, 50/60 Hz) 0.416 A @ 240 VAC
0.833 A @ 120 VAC
1 A @ ≤ 100 VSC
Max Current (DC) 0.833 A @ 120 VDC
1 A @ ≤ 100 VDC
Mount & Stem Materials 316L SS
Float Materials 316L SS
Length 3.44 in. – top of threads to bottom of stem
Width 2.06 in. – float diameter

Ref: apgsensors.com

Download Data Sheet: Stainless Steel Vertical Float Switch FS-400

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