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Jerguson® Side-Mount Level Switches

Jerguson® products are also available under the Magne-Sonics® brand as required based on approved vendor specifications.

Jerguson offers a wide array of mechanical switch and transmitter products to provide reliable level measurement for your application. Our caged level switch products feature a unique, tri-magnet mechanism that offers high current, snap-action switching without the use of cams or springs. 

Jerguson® JMRS Horizontal Mount Magnetic Reed Switch


  • Magnetic Actuation

  • All 316SS Wetted Parts

  • SPST3A Contacts

  • No O-Ring or Packing Seals

  • Hermetically Sealed Switch Mechanism

  • Hi or Lo Level Operation


The Jerguson JMRS series float operated magnetic reed switch is designed to provide reliable low cost switching.  Utilizing a magnetically actuated reed switch to provide a contact, switching occurs when the float moves a magnet into close proximity of the reed switch.  The float magnet and reed switch mechanism are isolated from one another by a non-magnetic stainless steel barrier.  The all stainless steel construction and hermetically sealed reed switch provides long life at a very low cost, without diagrams or other seals that can leak.

JMRS Horizontal Mount Magnetic Reed Swit

Jerguson® JMLS Horizontal Mount Magnetic Level Switch


  • Magnetic Snap-Actuation

  • All 316SS Wetted Parts

  • SPDT or DPDT Contacts

  • Integral Conduit Box

  • Magnetic Latching

  • CSA Certified, Class I, Division 1, Group C & D, NEMA 4X

  • Single Seal Per ISA 12.27.07-2011


Operation is achieved using the time proven principle of repelling magnetic forces.  One permanent magnet, the primary magnet, forms part of a float assembly which rises and falls with changing liquid level.  The secondary magnet is positioned within the enclosure so that the adjacent poles of the two magnets repel each other through a non-magnetic, stainless steel barrier.  A change in liquid level moves the float through its permissible range of travel causing the float magnet to pivot and repel the switch magnet.  The resulting snap action of the repelling magnets actuates the switch.

JMLS Horizontal Mount Magnetic Level Swi
Side-Mount Horizontal Float Operated Mag

Jerguson® Side-Mount Horizontal Float Operated Magnetic Level Switch


  • Tri-Magnet Switching for Unparalleled Reliability

  • Vibration Resistant

  • 316 Stainless Steel Trim

  • ASME B31.1 & B31.3 Design


The switch mechanism is based on a unique three-dimensional magnet design where the snap action is accomplished by the utilization of magnetic repulsion and attraction. The primary magnet mounted on the float rod causes the secondary magnet to rotate as it passes up and down. The tertiary switch magnet is repelled by the secondary and snaps to the opposite side. This causes the cradle to pivot, moving the push rods, which operate the switch contacts. The result is positive snap action, interlock switching…no springs…no spring problems!

The Float Chamber


The flanged chamber construction of this series of horizontal controls makes them a very serviceable level control solution for petrochemical, power generation and OEM applications.

The unique three-magnet system provides reliable switching for applications such as level alarm, safety shutdown and pump control in product storage tanks, gas scrubbers, process vessels, and high pressure steam generators.
Single switch only available. Chambers are designed to ASME B31.1, Power Piping Code, and ASME B31.3, Chemical Plant and Petroleum Refinery Piping Code.

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