APG Stainless Steel Vertical Float Switch FS-400

APG Stainless Steel Vertical Float Switch FS-400

Series FS-400 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.

APG Stainless Steel Vertical Float Switch FS-400 | Compact Size

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.


  • 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



Switch Points1 NO/NC
 Customer Reversible
Specific GravityMinimum 0.6
Pressure Rating200 psi / 13.8 bar (Standard)
 500 psi / 34.5 bar (High Temperature)
Normally Open Actuation0.220" ± 0.015"
 5.59 mm ± 0.38 mm
Normally Closed Actuation0.160" ± 0.015"
 4.06 mm ± 0.38 mm
Hysteresis0.070" ± 0.010"
 1.78 mm ± 0.25 mm


Switch Rating100 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 Materials316L SS
Float Materials316L SS
Length3.44 in. - top of threads to bottom of stem
Width2.06 in. - float diameter

Ref: apgsensors.com

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