The rugged Fisher  L2  liquid level controller uses a displacer type sensor to detect liquid level or the interface of two liquids of different specific gravities. This controller is ideal for controlling level on gas separators and scrubbers. The reliability of the  L2 design makes it well suited for liquid level applications in natural gas production, compression, and processing. The device delivers a pneumatic output signal to a control/dump valve. The sensor uses a threaded 2 NPT or an NPS 2 CL150 through 1500 slip-on flange connection to the vessel.


  • More Reliable Control – Two-stage proportional relay with integral action provides more dependable liquid level control.

  • Snap-Acting or Throttling Control-One standard controller available as either throttling or snap-acting.

  • Vibration Resistant Sensor Dynamics- O-ring friction and process pressure sensitivity are minimal. 

  • Performance stays constant with process pressure changes and controller remains vibration resistant.

  • NACE Service Ready-Standard construction uses materials that comply with the requirements of NACE MR0175-2002.

  • Field-Configurable Vertical or Horizontal Displacer- Displacer may be adjusted in the field for vertical or horizontal operation without additional parts.

  • Field-Reversible Output- The controller can be adjusted in the field for direct or reverse action without additional parts. The controller also has adjustable gain sensitivity.  

  • CL1500 Pressure Rating- Sensor assembly is designed and specified for ASME B16.34 CL1500 service when using a Polyvinylchloride (PVC) displacer. For PED (97/23/EC) maximum pressure is limited to 200 bar (2900 psig).

  • Vent-Away Case- The ability to pipe away exhaust permits using natural gas as the operating medium. 

  • Easy Maintenance-Both the controller and the sensor can be easily disassembled to inspect the process seals and for maintenance.