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Vaisala MM70 Handheld Moisture in Oil Meter

The Vaisala MM70 hand-held moisture in oil meter is a portable instrument for the preventive maintenance of oil-filled systems.  The MM70 measures moisture in oil in terms of the water activity (aw)  and temperature (T). Water activity (aw) considers degradation of oil condition and therefore acts as an indication of the risk of water formation. Water Activity is independent of oil type, age and temperature.

The Vaisala MM70 portable moisture in oil meter incorporates the Vaisala HUMICAP® Sensor. HUMICAP® offers excellent chemical tolerance to provide an accurate and reliable measurement of moisture in oil.  The MM70 has an embedded model for expressing moisture as ppm in mineral transformer oil. The customer can enter up to three other oil models into the meter’s memory.


The Vaisala MM70 Moisture in oil meter also offers a temperature measurement.  Additionally the indicator (MI70) will accept 2x probes to run simultaneously, including a range of dedicated dewpoint probes (from the DM70 range) , carbon dioxide probes (from the GM70 range ) and RH&T probes (from the HM70 range ).  The MI70 indicator includes a datalogging facility (2700 datapoints memory) and can be supplied with Windows® Software MI70LINK with USB interface for graphing of collected information.


Vaisala MM70 Handheld Moisture in Oil and Temperature Meter specifications…

  • Measurement range aw (water activity)  and ppm measurements
  • Shows measurement trends graphically (on the unit and via MI70LINK software)
  • Vaisala HUMICAP® Sensor technology for stability and reduced uncertainty of measurement
  • Compatible with Vaisala’s fixed oil moisture instruments
  • Multiprobe operation; dewpoint, RH&T and CO2 probes can also be connected
  • No reference oil needed for recalibration
  • Data can be logged, and transferred to a PC via MI70 Link software
  • Rugged and reliable – even in extreme conditions
  • NIST traceable (certificate included)


Fluidic are a recognised partner of Vaisala CEN (Industrial division) for Scotland and the North of England.  Our instrumentation engineers are product trained and able to help with instrument selection within the full range of Vaisala Moisture in Oil instrumentation.  Please call either office for more information (Glasgow 0141 641 5920,  Warrington 01925 572401).



  • Download Vaisala MM70 Portable Moisture in Oil meter Datasheet
  • Download Vaisala MM70 Portable Moisture in Oil meter User Guide
  • Download Monitoring Transformer’s Oil Moisture Level
  • Download Water Activity Level - Moisture in Oil Instrumentation
  • Download The Vaisala HUMICAP Sensor
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