Starting at $779.00

This probe currently has an exceptionally long lead time. If you would like to consider an alternative option, please call Instrumart to discuss your application.

Warning: Damage caused by freezing isn't covered by warranty; we recommend 2-day shipping to reduce risk.
  • Usually ships in 50 weeks



  • Wetted Materials: Tefzel, Viton, glass, ceramic
  • pH Glass Types: Hemi bulb and High pH glass
  • Insertion Depth: 2.8 in. to 5.5 in. (6.1 cm to 14 cm)
  • Sensor Design: Threaded connection for in-line or submersion mounting
  • Electrical Connection: Integral cable or VP connector
  • Temperature Compensation: 3K or Pt 100
  • Process Connection: 1 inch MNPT threads in two places
  • Triple junction reference


The Rosemount Analytical models 389 and 389VP are insertion style pH/ORP sensors with integral preamp. These sensors are compatible with nearly all Rosemount Analytical pH/ORP analyzers. Both models are combination sensors (pH, reference, and temperature within sensor body) and measure pH or ORP (Oxidation/Reduction Potential) of aqueous solutions in pipelines, open tanks, or ponds. Models 389 and 389VP are suitable for virtually all applications and are compatible with Rosemount Analytical and other manufacturers' instruments.

The Rosemount Analytical models 389 and 389VP are housed in a molded Tefzel body with Viton o-rings, making each sensor virtually indestructible and chemically resistant. The simplified construction, designed with user convenience in mind does not require electrolyte replenishment or any high maintenance troubleshooting procedures. The 389 features an integral cable design while the 389VP is offered with a watertight Variopol VP multiple pin sensor-to-cable connector which eliminates re-wiring and cable twisting when replacing sensors. Installation is easily achieved through the wide variety of mounting configurations. Both Models feature 1 inch (MNPT) front and rear facing connections for insertion, submersion, or flow-through pH and ORP applications.

Both the 389 and 389VP are provided with a triple junction reference which protects the reference element from harsh elements and helps prolong the sensor life. Both the 389 and 389VP require a preamplifier to convert the high impedance pH signal into a stable, noise-free signal. The 389 offers the choice of an integral sensor preamplifier. Both models can use a remote preamplifier, integral to the analyzer/ transmitter or in a remote junction box. All preamplifiers have a transmission capability of up to three miles.


This product can be used in the following applications: