666/668 (C) Single Actuator Chamber Mounted Switch

Models 666C and 668C are single actuator controls.  They  are short welded chambers with excellent low specific gravity and high pressure capabilities.  Each control is available with a wide variety of switches.  The controls use a short welded chamber which totally encloses the solid graphite displacer.  Connections are 1” NPT.

These controls may be used for interface applications on special order.  Consult the factory and specify specific gravity of both liquids.

Available temperature and pressure ratings for these controls is 150 to 1000 psig at 500º F. Special materials of construction are available.

Specific gravity and temperature affect the calibration of these controls.  These values must be specified when ordering.

Standard specific gravity setting is specified on Table A on the reverse side.   If the specific gravity of the liquid increases, the switching differential will decrease and take place at a lower point on the displacer.  If the specific gravity of the liquid decreases, the switching differential will increase and take place at a higher point on the displacer.  Consult the factory if the specific gravity of the liquid will vary more than 0.1 from the standard specific gravity shown.  Maximum specific gravity  for these controls is 1.7.


  • Factory Calibrated to each applications Specific Gravity
  • Hydrostatically Tested at 1.5 times the maximum design pressure
  • Available in CS, 304SS, 316SS
  • UL & CSA Approved

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