L-40N Liquid Level Switches


Side and Top Mount

Corrosion Resistant Plastic with Optional Metal Pivot Pin

  • Noryl Polyphenylene Oxide (PPO) is suitable for acid and base solutions, pure water, process water, sea water, filtered sewage, contaminated groundwater. Noryl is not suitable for use in hydrocarbons, petroleum, alcohol and related chemicals.
  • The wetted surface of Model L-40 is entirely of Noryl (PPO) except for a small float support Pivot Pin.
  • Float support pivot pin is supplied in a variety of materials i.e. 316 Stainless Steel, Hastelloy C-276, Titanium, Tantalum and Teflon to meet special chemical and operations environments.
  • 10 times less sensitive from deposit and build-up of contaminants than sliding float models.


  • Each unit can be supplied with a special made to order 1-1/4″ x 1/4″ x 1/2″ reducer bushing for through wall mounting.
  • Output wire can be twisted pair 22 gauge or two conductor PVC heavy wall instrument cable.
  • STANDARD – SPST reed switch for 120/240 VAC 50 Watt power or DC dry circuit for computer/PLC interface.

Wetted Surfaces

10% Glass reinforced Noryl (PPO) and 316 stainless steel pivot pin.

Nominal Working Pressure/Temperature

Tested to Failure at 800 psig at room temperature

Temperature °F (°C) 0° (-18°) 50° (10°) 100° (38°) 200° (93°)
Pressure (psig) 200 200 175 140


Working Fluid Spec. Gravity

Top Mount 0.8

Side Mount 0.7

Liquid Level Switch

Nominal ON/OFF Differential

≈ 3/8” (0.375”)

Electrical Switch Characteristics – STANDARD

  • SPNO
  • AC voltage (max. switching) 300VAC
  • DC voltage (max. switching) 350VDC
  • Current (max. switching) 0.5amp
  • Current (max. carrying) 2.5amp
  • Contact Rating (VA, W) 50
  • Capacitance (typical) 0.3pf
  • Insulation resistance 1010 ohms
  • Operation temperature
  • -40°F to 240°F
  • (-40°C to 115°C)

SPNC or SPDT, 3 Watt, 100VAC/VDC optional.

Float Pivot Pin available in:

316 Stainless, Hastelloy C-276 as standard; Titanium, Tantalum, Teflon as special order.

Corrosion Resistance

See compatibility table (see here).

Dry Circuit Operating

Switch can interface with microprocessor based controllers and related dry circuits.

Inductive Loads

Switch contacts have been tested with inductive relay and 30 amp motor contactor drive coils at 120 VAC and 240 VAC to 500,000 operations without failure. Maximum allowable volt amp (VA) rating of relay operating coil — 8.0 VA or less.

Installation Dimensions

NOTE: Model L-40 employs magnetic coupling between float arm and switch body. Magnetic particles can accumulate on and around magnetic housing which may affect proper operation. Please conduct appropriate fluid magnetic particle evaluation and operational tests prior to and during installation and use.

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