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  • Rugged, Versatile Design
  • Long Lasting Rebuildable Reference
  • Quick Connect Cable or Integral Cable
  • 0-14 pH range
  • Operating temp:
  • Model 3400HT; 41 to 311°F (5 to 155°C)
    • Model 3400HTVP; 293°F (145°C)
  • Ball valve process connection
  • VP8 Connector Cable in multiple lengths


The Rosemount Analytical Model 3400HT pH/ORP Sensor is designed for use at high temperatures and is fabricated with a Ryton® body. The sensor assembly is housed in a titanium tube and requires a process connector (PN 23166-00 or 23166-01, ordered separately) for installation. The sensor can be used in a ball valve (ordered separately) for hot tap (retractable) applications. The sensor includes a hemi glass pH electrode bulb, a Teflon® reference junction, and a Pt100 RTD for temperature compensation. Three wiring configurations are available: Variopol connector (3400HTVP), 9.5 inch lead for sensor head junction box mounting (-61), and 15 foot integral cable for connecting directly to an analyzer or transmitter(-62). Junction box kits with preamplifiers (ordered separately) are required if the sensor cannot be installed within 15 feet of the analyzer/transmitter. When used with integral preamp SMART option is standard (option 70). VP8 cable is required for SMART communication.

Rosemount Analytical PERpH-X™ High Performance pH / ORP sensors incorporate several design innovations that prolong the life of the pH sensor in difficult hot processes. High temperatures, fouling, coating and poisoning conditions cause increased deterioration of the glass pH sensing membrane, increased depletion of the reference electrolyte, and increased thermal stress on all sensor components. Use the Model 3400HT/3400HTVP to lower your total cost of ownership and avoid frequent sensor replacement.

The PERpH-X™ HT sensors contain an enhanced double junction reference that is excellent for extreme applications. The outer gel based reference retains viscosity to resist the pumping actions of temperature and pressure. A custom refill kit including a gel filled syringe is available as an accessory. Preventative maintenance of the outer reference can extend the ultimate life of the pH/ORP sensor considerably by preventing concentration changes in the inner reference. Reference flow into the process stream is controlled using a porous Teflon® junction that can be replaced in the event of fouling or plugging. The specially designed junction is chemically resistant and has a large surface area to maintain a steady reference signal in dirty or oily applications.


Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.


Mounting Bracket


Please consider these optional accessories.


This product can be used in the following applications: