Level Sensors & Switches

LS-3 Single-Point Level Switch

Part Number: 65656
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The durable construction of these reed switch designs ensures long, trouble-free service. Because the effects of shock, wear and vibration are minimized, these hermetically sealed level switches provide precise repeatability with no more than 1% deviation. The level switch actuation points remain constant over the life of the unit. Ideal for shallow tanks or restricted spaces, or for any low-cost, high volume use. LS-3 Series are available in FDA/NSF compliant materials upon request, consult Gems for details. NEW LS-3 MICRO: Gems' newest addition to the LS-3 series family is the LS-3 Micro. It is the smallest LS-3 series switch available. These units are ideal for potable water, medical devices and other compact appliances such as printers. Gems LS-3 Micro float enables use in lighter-than-water fluids. These switches are also made with FDA compliant material, which expands the scope in which these floats can be used.

  • Engineered Plastics
  • Ideal for Shallow Tanks
  • Low Cost/High Volume Use


  • Engineered Plastics
  • Ideal for Shallow Tanks
  • Low Cost/High Volume Use 
Sensor Type
Float Type
Primary Material Of Construction
Wetted Materials
Stem Material
Float Material
Float Diameter
Actuation Level
Min. Liquid SG
Maximum Pressure
50 psi
Minimum Temperature
Maximum Temperature
Mounting Size
1/8" NPT Male
Mounting Style
Electrical Termination
24" Long, 22 AWG, PVC Leads
Switch Type
SPST (50 VA)
Switch Operation
Normally Open (Reversible)

Reed Switch Protection

Format .pdf
Size 56 KB

Gems Sensors Instructions, Level Switches

Format .pdf
Size 553 KB

LS-3 Product Guide

Format .pdf
Size 1 MB

Gems Sensors Catalog, LS-3

Format .pdf
Size 785 KB
  • Food & Bev Equipment
  • Food & Beverage - Automated Water Dispense
  • Food & Beverage - Beverage dispensing
  • Food & Beverage - Ice makers
  • Food & Beverage - Other
  • Food & Beverage - Specialty dispensing
  • General Industry
  • General Industry - Appliance
  • General Industry - Car Wash Equipment
  • General Industry - Environmental
  • General Industry - Fountains
  • General Industry - Laser Equipment
  • General Industry - Other
  • General Industry - Plastics & Packaging
  • General Industry - Purifiers
  • HVAC/R - Air Conditioning Systems
  • HVAC/R - Chillers
  • HVAC/R - Evaporators
  • HVAC/R - General HVAC
  • HVAC/R - Heating/Condensate Systems
  • HVAC/R - Humidifers
  • HVAC/R - Other
  • HVAC/R Equipment
  • Medical - Imaging
  • Medical - Immunochemistry
  • Medical - IVD
  • Medical - Lab
  • Medical - Laboratory & Testing
  • Medical - Life Sciences
  • Medical - Medical Lasers
  • Medical - Other
  • Medical - Radiology
  • Medical - Renal Care / Dialysis
  • Medical Equipment
  • Printers
  • Semicon Equipment
  • Semiconductor - Gas Cabinets
  • Semiconductor - Other
  • Semiconductor - Semiconductor Equipment
  • Waster Water Applications
  • Water & Waste Water - Other
  • Water & Waste Water - Point of Use
What is the LS-3 Micro?

It is a subminiature point level switch designed to provide high performance in space-limited applications such as medical diagnostic devices, food & beverage machines, etc. These switches are compatible with water, medical reagents and corrosive chemicals.

What is the operating principle for the LS-3 Micro?

It operates on a direct, simple principle. A float encircling a stationary stem is equipped with permanent magnets. As the float rises or lowers with the liquid level, the magnetic field generated from within the float, actuates a hermetically sealed magnetic reed switch mounted within the stem.

Why does the LS-3 Micro have a special fluted stem design?

The special fluted stem design, coupled with lighter magnets and bumps on the float, reduces the likeliness of sticking and improves the buoyancy, reliability and performance of the sensor.

What is the accuracy of a reed switch?

The design of the reed switch provides consistent accuracy of +/- 1/16".

What is the life expectancy of a reed switch?

A reed switch is extremely rugged and designed to operate reliably for many years, under ideal conditions, up to about 2 million cycles. To achieve maximum service life, reed switches benefit from protected electrical supply.

Does the LS-3 Micro have FDA approval?

No, but the materials of construction are consistent with FDA approvals for potable water.

What is the electrical rating for the LS-3 Micro?

20 Watt, 140 VAC/200VDC, 500mA, switch current.

Can the LS-3Micro float be reversed to get the opposite operation?

No, the float cannot be reversed. We have special part numbers for normally open and normally closed in each mounting style.

What mountings are available for LS-3 Micro?

We currently offer 1/8"NPT thread and 3/8"-16 UNC thread. Contact Gems if another mounting is required for qualified high volume OEM applications.

What is the best position to mount the LS-3 Micro?

The sensor can be mounted tank top or tank bottom mounted vertically, with lead wires up or down.

Are longer lead wires available for the LS-3 Micro?

Yes, we can do longer lead wires. A minimum purchase would be required. Contact Gems with your requirements.