• SMART enabled
  • Available in hemi bulb, flat bulb, HF resistant, and Hi pH glass
  • Special features for processes with low conductivity, hydrofluoric acid, high pH, and reference poisoning elements
  • Watertight VP8 multiple-pin connector available which eliminates cable twisting.
  • Double or triple junction reference cell
  • Various mounting options
  • Sealed PPS body provides maximum protection
Non-in-stock probes will have a black resin color, no other difference in manufacture.


The Rosemount Analytical 3900 and 3900VP General purpose pH/ORP sensor models are provided with a double junction reference, which protects the reference element from poisoning ions – such as ammonia, chlorine, cyanides, and sulfides – in the process. The double junction reference aids in the sensor's resistance to harsh environments and helps prolong sensor life. Both models are made with porous Teflon® junction positioned near the pH/ORP-sensitive membrane.

The AccuGLASS pH glass formulations exceed industry standards. The AccuGlass pH glass is a result of many years of glass research resulting in a formulation which has been found to increase the life of the sensor. Unlike other pH glasses presently on the market, this glass resists cracking especially at higher temperatures and reduces sodium ion error commonly found in high pH applications. Overall, the AccuGlass formulation enhances the sensor performance to measure pH more accurately and have a longer sensor life than ever before.

Model 3900VP is offered with a watertight sensor-to-cable connector which eliminates re-wiring and cable twisting when replacing sensors. The Variopol VP multiple pin connector is an integral part of each sensor model and uses a mating VP cable. Once the cable is installed and wired to the analyzer, sensors are easily replaced without replacing the cable and without rewiring the analyzer. Also the cable can be disconnected from the sensor before removal from the process which eliminates cable twisting.

Models 3900 and 3900VP are housed in a molded PPS body, making each sensor virtually indestructible and chemically resistant. Complete encapsulation eliminates leakage or high humidity problems traditionally found in other pH/ORP designs. The simplified construction, designed with user convenience in mind does not require electrolyte (KCl) replenishment or any high maintenance troubleshooting procedures.

Installation is easily achieved through the wide variety of mounting configurations. Both Models feature 1'' and 3⁄4'' inch (MNPT) front facing connections for insertion, submersion, or flow-through pH and ORP applications.

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 3900 and 3900VP are suitable for virtually all applications and are compatible with Rosemount Analytical and other manufacturers' instruments.


In Stock

Part Number Style Preamplifier Measurement Type Price Available
Sensor with VP8 connector
SMART Preamplifier (Standard Preamp if used with ORP)
General Purpose Low Resistivity pH Glass (0-14pH)
$635.00 4 in stock

Interested in Other Part Numbers?

Other part numbers are available to order but are not currently in stock. Current availability for non-stock parts is "Usually ships in 6-8 weeks". Click here to select options