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10540 Rockley Road
Houston, TX 77099

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C621 & C621H Stainless Steel Conductivity Probes TEXT SIZE: A A A    PRINT THIS PAGE   EMAIL THIS PAGE

The Model C621 & C621 H conductivity electrode provides rugged construction and long term stability through the use of specially treated 316 stainless steel. This probe is engineered to minimize errors due to polarization effects, and respond rapidly to changing temperatures. The C621 series is compatible with most conductivity transmitters that are designed for a standard two electrode cell (not a 4-cell type).

Standard Features

  • In-Line Installation
  • Temperature Compensation
  • Treated 316 Stainless Steel Body
  • Cell Constant Validated At The Factory
  • C621: IP 65 Detachable Plastic Cable Connector
  • C621H: NEMA 4 Aluminum Threaded Terminal Box
  • Temperature Sensors: 10K NTC, PT100 and PT1000


  • Temprature Range C621: 0 to 140°C
  • Temprature Range C621H: 0 to 205°C
  • Maximum Pressure C621: 150 psig at 135°C
  • Maximum Pressure C621H: 250 psig at 205°C
  • Wetted Materials: 316 Stainless Steel and PEEK
  • O-Rings: Viton1
  • Cell Constants: K=1.0, K=0.1 and K=0.01
  • Process Fitting: 1/2 and 3/4 Inch in either NPT or BSP Male Fittings

To ensure compatibility with your test sample, please choose a cell constant and temperature element prior to ordering.

Cell Constant of K=1.0 Drinking water, service water, beer, milk and juice.
Conductivity Ranges: 10 to 2000 µS/cm at 25°C.
Cell Constant of K=0.1 High purity water such as condensate and boiler feed water in power plants.
Conductivity Ranges: 0.5 to 200 µS/cm at 25°C.
Cell Constant of K=0.01 Specific resistivity or conductivity for monitoring ion
exchangers, reverse osmosis systems, ultrapure water
for the medical and electronics industry.
Conductivity Ranges: 0.055 to 20 µS/cm at 25°C.


1 A registered trademark of E.I. du Pont Nemours and Company