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Factory Recalibration / Certification
The Kestrel should be recalibrated if the RH sensor has shown drift in its RH measurement. The Kestrel RH
sensor is specified to develop less than 2% drift over 24 months. You may return your Kestrel to NK for
Factory Recalibration of the relative humidity and related measurements. Recalibration is available with and
without certification of NIST traceability and calibration stickers. Note that NK can recalibrate and certify any
of the values measured by your Kestrel. Please contact NK for more information about Factory Recalibration
and certification.
Field Recalibration
As an alternative to Factory Recalibration, this kit allows you to perform dozens of humidity recalibrations in
the field to ensure that your Kestrel is always performing within specifications. This manual explains in detail
all of the steps for recalibrating your Kestrel’s humidity Sensor. This process will take approximately 50 hours,
including setup and calibration.
Ensure that you are performing the calibration in a climate controlled environment such as a home or office
and make sure your calibration location is not near any windows or air conditioning or heating vents. Even
temperature changes as slight as 2 deg F while calibrating can negatively impact accuracy so if you are
not sure that your calibration environment is stable enough, or to ensure an accurate calibration, place the
entire Cal Kit inside an insulated cooler or if a cooler is not available, wrapped in a thick blanket. Further
temperature control can be gained by placing additional containers of room temperature water inside the
cooler or blanket, (gallon jugs work fine).
Please read ALL of these instructions before
beginning the recalibration of your Kestrel!