APG Pneumatic Level Switch NLS

APG Pneumatic Level Switch NLS

APG's story begins with a Utah State University graduate using his engineering skills to make a difference in the lives of farmers. Cordell Lundahl designed an ultrasonic sensor and control system that could guide farm machinery around the uncut edge of a field. A farmer, riding in a second machine, could effectively make two cuts with one pass leaving more time for all the other unending farm chores. Fast-forward 40 years, and APG now offers a full line of level sensors and switches, pressure transducers, and data management tools to help everyone from farmers to chemists, and waste managers to food and beverage producers control their processes and inventories.

Pneumatic Level Switch NLS

The Series NLS pneumatic liquid level switch is designed for use in high viscosity liquids. It is modified to overcome the high viscosity by making the tip of the detecting pipe larger than usual. The NLS is the ideal sensor for applications where electrical power is not available or hazardous conditions exist. Using a diaphragm, the switch is actuated by compression of a captive air column in the detecting pipe beneath the diaphragm. Unique level switch for viscous materials. Viscous and sticky liquids can stop a float switch in its tracks. The NLS is the answer.

Long Life

With few moving parts, only a flexing diaphragm, the NLS pneumatic point level sensor lasts long and is very reliable.

Low Power Operation

The NLS requires no power to operate it sensing elements, and provides a dry contact output.

Field Adjustable

Install a ½ in. pipe of your choosing in the bottom of the sensor housing, protruding past the switch point in the tank. The switch point is easily adjusted by your choice in pipe length.


  • Low cost - requires only a standard 1/2 in pipe
  • Simple installation
  • Rugged and reliable
  • Long switch life



Operation1 SPDT switch
Detection Range8 to 200 in.


Output Contact Rating250 V, 10 A AC, 115 V, 0.5 A DC (resistive)


Housing CoverADC12 or SS41
HousingADC12 or Phenolic
ChamberADC12, SCS13, or Phenolic
DiaphragmNeoprene® or Viton®
Cable EntryPF ¾ or Gasket 6Ø


Wiring2 conductor lead wire


Operating Temperature-4 to 158° F
Enclosure ProtectionIP42/NEMA 4

Download Data Sheet: Pneumatic Level Switch NLS

Ref: apgsensors.com

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