Kestrel 4200 User manual

NK
Instruction Manual
Kestrel®4200
Pocket Air Flow Tracker
Kestrel® 4200 Pocket Air Flow Tracker
FRONT
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MANUAL MEMORY BUTTON
Press to manually store current
conditions to memory.
MEASUREMENT BUTTONS
Press to scroll between screens:
Date/Time, Measurements,
User Defined Screens
POWER/SETUP BUTTON
Hold to turn power on or off. Press
to enter and exit Main Setup Menu.
BACKLIGHT BUTTON
Press to activate
backlight for 1 minute.
COMMAND BUTTON
In Chart Screens, press
to view data points.
In Setup Menus, press
to make selection.
MODE BUTTONS
Press to change mode of
measurements: Current,
Min/Max/Avg, Chart.
BACK
3
Kestrel® 4200 Pocket Air Flow Tracker
TEMPERATURE SENSOR
Hermetically sealed
precision thermistor
coiled to isolate from
case temperature.
HUMIDITY SENSOR
Capacitive sensor with
secondary thermistor to
improve accuracy and
response.
IMPELLER
Sapphire jewel bearings
on a user-replaceable
impeller.
IMPELLER COVER
Swivel cover protects
impeller when not in use.
DATA UPLOAD OPTICAL COUPLER
Software and serial port
interface sold separately.
BATTERY DOOR
Sealed with o-ring to keep
product watertight.
SERIAL NUMBER
2 AAA BATTERIES
PRESSURE SENSOR
Monolithic silicon
piezoresistive sensor.
Do NOT insert any
objects into this hole.
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Congratulations on the purchase of your Kestrel 4200 Pocket Air Flow Tracker! The Kestrel 4200 is our
newest and most comprehensive HVAC-specific meter. It not only measures EVERY environmental
condition easily, accurately, and right in the palm of your hand, but now also automatically calculates
Volume Air Flow (CFM) and Humidity Ratio (grains).
While the Kestrel 4200 is user-friendly and simple to use, reading the instruction manual is
recommended in order to use the Kestrel 4200 to its fullest potential.
NK, manufacturer of Kestrel Pocket Air Flow Trackers, is available to answer questions and provide
support. Contact NK by phone: [phone], fax: [phone], email: [email protected], or
web: www.kestrelinstruments.com
Getting Started
Pouch and Lanyards 5
Battery Installation 5
On/Off 5
Date and Time Set Up 5
Screen Navigation
Measurements and Modes 6
Charts 7
Special Functions
User Screens 7
Air Flow, Air Velocity & Wind Chill Averaging 7-8
Backlight 8
Air Flow Readings 8-9
Manual Data Storage 9
Accurate Humidity Readings 9-10
Barometer/Altimeter Adjustments 10-12
Main Setup Menu 12-16
Application Examples 17-18
Memory Capabilities 18
Glossary 19-20
Factory Default Settings 21
PC Upload 21
Customer Service
Warranty 22
Calibration, Certification & Service 22-23
Lifetime Customer Care Warranty 23

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Pouch and Lanyards
Wrist and neck lanyards and a small pouch have been provided. To install the
lanyard, feed the thin end of the lanyard around the metal post on the battery door
(as shown in diagram). Feed the thick end of the lanyard through the loop on the
thin end. Using tweezers can help.
Battery Installation
Use only AAA batteries. Install batteries as indicated on the battery door.After installing the batteries,
the Kestrel 4200 will automatically start in the Date and Time Setting mode. (See Date and Time Setup
below.) Custom settings and chart data will be saved during a battery change; only the date/time
and MMA values will be lost.
Turning the Kestrel 4200 ON and OFF
To turn the Kestrel ON, press the button. To turn the Kestrel OFF, hold the button for two
seconds. Or, press the button, then press the button with the word OFF highlighted. (Note: your
unit will continue to automatically store data when the power is turned off.)
Date and Time Setup
The first time that you turn on your Kestrel 4200, as well as after a battery change,
you will need to set the date and time. The Introduction Screen will appear for 3
seconds, followed by the Date/Time Setup Screen. Press the and buttons to
scroll through the settings. Press the and buttons to scroll through the setting
options. After entering the date and time, press the button to exit the Date/Time
Setup. Then press the button again to exit the Main Setup Menu.
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The Kestrel 4200 is set up to display 12 Measurements (some are calculations)
in 3 Modes.
The Measurements are listed to the left with their corresponding screen icon.
In addition to these Measurements and Modes, there are also 3 User Screens,
which simultaneously show 3 current measurements (see pages 8 and 15
for more information); and the Date & Time Screen, which gives the current
date and time. Use the and buttons to scroll through the various
Measurements, followed by the 3 User Screens and the Date/Time Screen.
The Modes are displayed below. Use the and buttons to scroll through
the various Modes. From any mode, you may still scroll to a different
Measurement by pressing the and buttons.
Current - displays the instantaneous reading
Min/Max/Avg - displays the Minimum/Maximum/Average readings from
stored data. If there is no stored data, the values will be displayed as --.-.
Chart - displays a graphical representation of up to 1600 stored data
points for each measurement.If there is no stored data, the axis will appear,
but the chart will be blank. (See the following page for information on
Chart Navigation.)
Air Flow
Air Velocity
Temperature
Wind Chill
Humidity
HUM
RATIO
Humidity Ratio
Heat Index
Dew Point
Wet Bulb
Barometric Pressure
Altitude
Density Altitude
DP
HI
D
WB
Current Min/Max/Avg Chart
Modes use
Navigation of Charts
The Kestrel 4200 is capable of storing up to 1600 data points for
each measurement. To review the data, press the button while
viewing a chart. A cursor will appear on the most recent data point.
Press the and buttons to scroll through the data points. The
date and time at which the data was stored will be displayed at
the bottom of the screen, and the data value will be displayed at the top of the screen. Hold down
the or button to scroll quickly through the data points.
Press the or button to review the data for the other measurements. Please note that the cursor
will remain at the same date and time. If new data is stored while viewing chart data, the entire chart
will shift left with the new data point charted on the right. The cursor will not shift with the chart.
Press the button to return to the Chart Mode.
User Screens
The Kestrel 4200 has three User Screens which can be customized to display three
current measurements simultaneously. (See page 15 for setup instructions.)
Max/Avg for Air Flow,Air Velocity & Wind Chill
The Max/Avg values for the Air Flow, Velocity and Wind Chill values are measured independently
from the stored and charted data. This allows the user to start and stop the averaging period in the
most appropriate manner for their application. Averaging on all velocity-related values (Air Flow, Air
Velocity and Wind Chill) will be started and stopped together.
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While viewing the Min/Max/Avg screen for any of these measurements, hold the unit into the wind,
and press the button when the screen displays “--average” to begin collecting data for all
measurements, and again when the screen displays “--stop” to stop collecting data and hold the
values on the display. Press the button when the screen displays “--clear” to clear the data. This
routine will work simultaneously for all measurements, regardless of which one is displayed while
the routine is run. The Min/Max/Avg for these velocity values will not affect any other Min/Max/Avg
or stored data.
Backlight
The Kestrel 4200 has a high-visibility green backlight, which makes the display easily read in low-
light conditions.
Press the button to activate the backlight. The light will remain activated for one minute. Press the
button within one minute to deactivate the light manually.
Air Flow
The Kestrel 4200 will display the volume air flow, based on the instantaneous air velocity and cross-
sectional area of the opening through which the air is passing. If your particular industry uses a
standard of practice for air flow measurements, be sure to adhere to those standards when using this
product.
To set the dimensions of the duct or opening,press the button while viewing the AIR FLOW screen.
The DIMENSIONAL SETTING screen will appear with the word SHAPE highlighted.
The shape of the opening can be selected by pressing the or button. The options are round or
rectangular openings. Press the button to highlight the dimensional settings. For round openings,
simply set the correct diameter of the opening. Use the and buttons to increase and decrease
the value. Holding these buttons will increase and decrease the value quickly. For rectangular
openings, set both the length and the width of the opening.
Value
Chart
Cursor
Date & Time
Measurements use

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While viewing the Min/Max/Avg screen for any of these measurements, hold the unit into the air
flow, and press the button when the screen displays “--average” to begin collecting data for all
When the dimensional settings are correct, press the button to exit the DIMENSIONAL SETTING
screen and return to AIR FLOW screen. The displayed air flow value will be the result of multiplying
the instantaneous air velocity by the area of the programmed opening.
Note that you may change the units for setting opening dimensions under the Main Setup Menu
(see page 14 for instructions). Choices are inches, feet, centimeters and meters.
The Kestrel 4200 also features an averaging function that allows you to traverse a duct and the
unit automatically averages the CFM. This method may yield more accurate results, especially in
ducts with variable flow or with registers on them.To do so, from the current Air Flow screen, simply
press the button to enter the Max/Average screen. Press the button to begin averaging, and
traverse the duct. When finished, press the button again to stop the averaging. Press to clear
the data. See pages 17 - 18 for more information.
Manual Data Storage
In addition to automatic readings, the Kestrel 4200 can also take readings manually. Simply press
the button to store all the presently measured values in memory with date and time. Readings
taken manually will appear chronologically within the automatically store data in the chart. Manual
Data Storage may be disabled - see page 13 for Manual Data Storage settings.
Relative Humidity
The Kestrel 4200 is capable of measuring RH to a high accuracy: ± 3% RH. To ensure the Kestrel
4200’s ability to operate within these specifications, follow these recommendations:
• Avoid taking measurements in direct sunlight, which will heat the air inside the humidity sensor
enclosure and cause inaccurate readings.
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• If your circumstances force you to expose the Kestrel to a large temperature swing prior to
taking a relative humidity reading (such as when taking a Kestrel stored inside at 70° F outside
to a temperature of 40° F), you will need to take additional steps to ensure that the Kestrel’s
external temperature sensor is in thermal equilibrium.
- Ideally, provide an airflow of at least 1 M/S (2.2 MPH), over the temperature sensor, moving from
the back of the unit towards the front. (In other words, point the Kestrel into the airflow.) If there
is no airflow, simply wave the Kestrel back and forth so air passes over the sensors. With airflow
over the temperature sensors and humidity chambers, readings within specifications will be
provided within two to three minutes, even after a large temperature shift.
- If no airflow can be provided, you must allow sufficient time for the RH value to stabilize. This
can take as long as 20 minutes- the greater the temperature change, the greater the time. You
can use the logging capability of the Kestrel 4200 to confirm that the unit has stabilized to a
correct reading: Set the memory options to a relatively short logging interval (20 seconds
works well, see page 14 for instructions), select the graphical display of RH, and you can see
when the value is no longer changing significantly. At that point, the RH value is stable and
can be relied upon to be within the accuracy specifications.
Barometric Pressure and Altitude Adjustment
The Kestrel 4200 measures station pressure - the actual air pressure in the measurement location -
and uses this value to calculate barometric pressure and altitude. Station pressure changes in response
to two things - changes in altitude and changes in the atmosphere. Because the Kestrel 4200 is
constantly changing location and altitude, it is important to enter adjustments or “references” when
accurate pressure and altitude readings are needed.
Barometric pressure is station pressure corrected to sea level. In order to make the correction, the
Kestrel 4200 needs an accurate reference altitude. Altitude is the height above sea level. In order to
correctly calculate altitude, the Kestrel 4200 needs an accurate barometric pressure reference, also
known as an “altimeter setting”. You only need to know ONE of these values (current barometric
pressure or current altitude) in order to set your Kestrel up to show accurate readings.
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Starting with the known barometric pressure for your location
You can obtain your current barometric pressure by checking an internet weather
site for a nearby location, or contacting a local airport. Set this value as your
reference pressure on the ALTITUDE screen to determine your correct altitude:
Press the button to enter the reference setting mode. Press the button to
increase the reference pressure or the button to decrease the reference pressure.
You will notice that the altitude will change with changes in the reference pressure. Press the
button to exit the adjustment mode. Set your Kestrel down on a table and allow the altitude
reading to stabilize. (Note: very small changes in pressure generate noticeable changes in altitude.
In order to provide meaningful readings for activities where altitude changes quickly, the Kestrel
4000 features rapid altitude response. This is why the altitude readings tend to fluctuate by a few
feet.) After obtaining a current altitude from the ALTITUDE screen, move to the BARO screen and
enter this value as your reference altitude by following the same procedure. Both readings will
now be accurate.
Starting with a known altitude for your location
You can obtain your altitude from a topographical map or local landmark. Google
Earth is an excellent free program that provides the exact altitude for any given
address: earth.google.com/. Set this value as your reference altitude on the BARO
screen to determine your barometric pressure: Press the button to enter the
reference setting mode. Press the button to increase the reference altitude or the button to
decrease the reference altitude. You will notice that the barometric pressure will change with
changes in the reference altitude. Press the button to exit the adjustment mode. Again, allow the
Kestrel to stabilize, then enter the value from the BARO screen as your reference pressure on the
ALTITUDE screen by following the same procedure. Both readings are now accurate.
When reviewing stored data, remember that changes in pressure AND changes in location/altitude
will affect the stored values. When tracking pressure changes relative to weather, set the reference
altitude on the BARO screen and keep the Kestrel in one location. Your graph history will now show
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trends in barometric pressure. Your altitude as shown on the ALTITUDE screen will change as the
pressure changes, but you can ignore this screen for this purpose.
In general, changes in barometric pressure associated with weather changes are small over the
course of one day, but they will affect the accuracy of the altimeter over time.This is why aircraft reset
their altimeters at every airfield by entering the field’s “altimeter setting” or reference pressure.
Accordingly, if accurate altitude readings are your primary interest, you should reset the reference
pressure on your Kestrel regularly. If you encounter an elevation landmark, you can adjust the
reference pressure until the altitude matches the landmark elevation. This will correct the altitude for
any pressure changes due to the weather. (Or, you can obtain an updated reference pressure from the
sources described above.)
Some final notes - If you wish to know the actual or station pressure for your location, simply set the
reference altitude on the BARO screen to“0”. In this case, the Kestrel will not make any adjustment and
will display the measured value. And, the above discussion applies to ALL pressure altimeters,
including one you may have in a watch or other device, but not to GPS altimeters which use satellite
triangulation to determine altitude. Note that with present GPS technology, pressure altimeters
remain more accurate for measuring altitude change. This is why airplanes still rely on pressure
altimeters, not GPS. Finally, the DENSITY ALTITUDE screen is calculated from the absolute values of
station pressure, relative humidity and temperature, and is not affected by the reference values
entered in the BARO and ALTITUDE screens.
You can customize your Kestrel 4200 in multiple ways. Press the button to access the Main Setup
Menu. Press the button to select the highlighted setting. The Main Setup Menu contains: OFF,
Memory Options, Measurements, Graph Scale, Units, User Screens, System, Date & Time, Language and
Restore.

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Off - Press the or the button to turn the display off. Even when the Kestrel’s display is turned
off, the unit will continue to automatically store data at the defined Store Rate. Wind speed will NOT
be stored when the unit is off. To continuously measure wind speed, turn the auto shutdown off,
and see page 8 for more information on how this data is stored. The battery life will be decreased
if data is stored frequently. The only way to completely shut off the unit is to remove the batteries.
Custom settings and data will be stored when the batteries are removed.
Memory Options - These settings control the data storage properties.
Setting Description Operation
Clear Log All stored data is cleared. This will also clear Min/Max/Avg data. Press or to clear
(Go/Done) the log.
Reset MMA All Min/Max/Avg data is cleared. Chart data will remain intact. Press or to clear
(Go/Done) the MMA.
Auto Store When On, data is automatically stored at preset Store Rate. When Off, Press or to toggle
(On/Off ) data is only stored when manually captured with the button. between On and Off.
Store Rate* The frequency at which data sets are automatically stored. Press or to increase or
(2 sec - 12 hr) (Battery life may be shortened if data is stored frequently.) decreaseStore Rate frequency.
Overwrite This setting only applies when the data log is full. When On, oldest Press or to toggle
(On/Off ) data point is discarded to allow memory for the new data point. between On and Off.
When Off, new data points are not saved.
Man Store When On, data is stored when the button is pressed. Press or to toggle
(On/Off ) When off, the button is disabled. between On and Off.
* When unit is off, data is NOT stored for 2 sec and 5 sec Store Rates.
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Measurements - Measurement screens can be hidden from the normal measurement navigation. For
example, if wind chill is not of interest, it can be hidden. Press the or button to toggle between ON
and OFF for each individual measurement. Press the or button to highlight the desired
measurement. Press the button to return to the Main Setup Menu.
Graph Scale - These settings control the chart limits of your meter. Depending on the conditions, the
lower and upper limits of the chart scale may need to be adjusted in order to get the best view of the
data. Highlight the desired measurement by pressing the or button. Select the highlighted
measurement by pressing the button. Press the or button to increase or decrease the value of
the limits. Press the or button to change between the upper and lower limits. Press the button
to exit and return to the measurement selection screen. Press the button to return to the Main
Setup Menu.
Units - The units of measure can be adjusted to best suit the application. The following units are
available:
Air Velocity Air Flow Dimensions
m/s meters per second cfm cubic feet per minute ft feet
km/h kilometers per hour m3/h cubic meters per hour cm centimeters
kt knots m3/m cubic meters per minute m meters
mph miles per hour m3/s cubic meters per second in inches
fpm feet per minute L/s liters per second
Bft Beaufort
Humidity Ratio Temperature, Pressure Altitude,
gpp grains per pound Dewpoint, Wet inHg inches mercury Density Alt.
g/kg grains per kilogram Bulb Temp, Wind hPa hectopascals m meters
Chill & Heat Index psi pound per square inch ft feet
°C Celsius mb millibar
°F Fahrenheit
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Highlight the desired measurement by pressing the or button. Press the or button to scroll
through the available units. Press the button to return to the Main Setup Menu.
User Screens - The three User Screens can be reconfigured to display the most appropriate
information for the application. Only current measurements can be selected for the User Screens -
Min/Max/Avg and Charts are not available.
Highlight the desired User Screen by pressing the or button. Press the button to select the
highlighted User Screen. Press the and buttons to change lines, and the or button to scroll
through the available measurements for each highlighted line. Press the button to return to the
User Screen Setup Menu. Repeat above process for the other User Screens or press the button to
return to the Main Setup Menu.
System - The display Contrast and Auto Shutdown can be reconfigured as required. The relative
humidity and pressure sensors can also be recalibrated. Press the and buttons to highlight the
appropriate selection, and the or button to adjust or select.
The Contrast can be adjusted for better visibility depending on the ambient lighting conditions.
Press the or button to increase or decrease the contrast from 0 to 20 (0 is lightest, 20 is darkest).
The display can be set to automatically turn off in order to conserve the battery life. Auto Shutdown
will only occur after the preset time has elapsed without any button presses. Press the or button
to scroll through the Auto Shutdown options (15 minutes, 60 minutes, Off).
Baro Cal - The pressure sensor can be calibrated if necessary. It is extremely important to know the
precise altitude and mean sea level barometric pressure at the time of calibrating the sensor. First,
set the reference altitude on the BARO measurement screen to the known altitude (see Pressure
Adjustment on page 9). Then adjust the calibrating setting on the Baro Cal screen to the known
mean sea level barometric pressure. Recalibration of this sensor is not typically required, and it is not
recommendedthat you recalibrate without speaking to an NK technician.
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Humidity Cal - The humidity sensor can be calibrated by “teaching” it the correct humidity. Some
special equipment is required for this calibration, including two hermetically sealed containers and
saturated salt solutions. NK offers a calibration kit, and instructions are available on www.nkhome.com.
Recalibration of this sensor is not typically required, and it is not recommended that you recalibrate without
speakingto an NK technician.
Date & Time - The date and time, as well as date and time formats, can be adjusted. The Time Formats
available are: 12 hour and 24 hour. The Date formats available are day/month/year and month/day/
year. (See page 5 for instructions on how to set the date and time.) Press the button to return to
the Main Setup Menu.
Language - Displayed text can be set in one of five languages: English, French, German, Italian or
Spanish. To choose a language, use the and buttons to highlight the desired language. Press the
button to select the language and return to the Main Setup Menu. Otherwise, press the button
to return to the Main Setup Menu without changing languages.
Restore - Default settings for units of measure, date and time formats, and system settings can be
restored. (See page 21 for a list of the default settings. ) Press the or button to highlight the
desired default setting: Metric, Imperial or Defaults. Press the or button to reset the factory setting.
Press the to return to the Main Setup Menu.

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The below definitions have been greatly simplified in order to keep this section brief. We strongly
recommend that anyone who wishes to make use of these measurements refer to one of the
many excellent weather references available for a more in-depth definition. On the internet, visit
www.usatoday.com or www.noaa.gov.Or,locate the USA Today publication,TheWeather Book.Please
note that any words in a definition printed in italics are themselves defined in this glossary.
Air Flow: The volume of air passing through an area for a given period of time. This is commonly
calculated by multiplying the air velocity by the cross sectional area through which the air is
passing.
Altimeter Setting: An aviation term for the local barometric pressure. Same as reference pressure.
Altitude: The distance above sea level. The Kestrel 4200 calculates altitude based on the measured
station pressure and the input barometric pressure - or “reference pressure”.
Barometric Pressure: The air pressure of your location reduced to sea level. Pressure will change as
weather systems move into your location. Falling pressure indicates the arrival of a low pressure
system and expected precipitation or storm conditions. Steady or rising pressure indicates clear
weather. A correct altitude must be input for the Kestrel 4200 to display barometric pressure
correctly.
Density Altitude: The altitude at which you would be, given the current air density. Often used by
pilots in order to determine how an aircraft will perform. Also of interest to individuals who tune
high performance internal combustion engines, such as race care engines.
Dewpoint: The temperature to which air must be cooled in order for condensation to occur. The
difference between dewpoint and temperature is referred to as the “temperature/dew point spread”.
A low dewpoint spread indicates high relative humidity, while a large dewpoint spread indicates dry
conditions.
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This section provides examples of applications where a Kestrel 4200 might be used, and the appropriate
memory settings.
HVAC - Environmental Monitoring
Auto Store On Store Rate 5 min
Overwrite On Man Store Off
These settings will record conditions every five minutes, for a total storage of almost 7 days. You can
monitor the conditions in a laboratory or manufacturing plant, both day and night, to determine if
the climate control is working properly. Or you can examine the effect on the environment when
employees enter and exit the building.
HVAC/R - System FunctionVerification
Auto Store Off Store Rate —
Overwrite Off Man Store On
These settings will require you to press the Manual Store Button in order to store any data at a duct,
hood, vent, or other system location. The meter will not store any data automatically. Be sure to
record the location an date/time of storage for reference when reviewing the data. After storing the
conditions at each location, simply review the data and balance the system.
Air Duct Measurements
There are two useful techniques for measuring air flow in a duct or at the face of a duct opening.
First, the unit can be used in the Max/Avg Mode (see page 9). Hold the unit in one corner or side of
the duct. Press the button to begin the averaging interval. Slowly traverse the duct. Press the
button at the end of the traverse of the duct. The maximum and average air flow measurements will
be displayed.
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Second, the unit can be used to store the air flow at multiple points in a duct. Hold the unit in one
position in or on the duct. Press the button to manually store the measurements (see page 9).
Repeat this process in multiple positions in or on the duct. When complete, review the stored
measurements in the chart data (see page 7), and average them if desired.
Store Rate Total Memory
2 sec 53 min, 20 sec
5 sec 2 hr, 13 min, 20 sec
10 sec 4 hr, 26 min, 40 sec
20 sec 8 hr, 53 min, 20 sec
30 sec 13 hr, 20 min
1 min 1 day, 2 hr, 40 min
2 min 2 days, 5 hr, 20 min
5 min 5 days, 13 hr, 20 min
Store Rate Total Memory
10 min 11 days, 2 hr, 40 min
20 min 22 days, 5 hr, 20 min
30 min 33 days, 8 hr
1 hr 66 days, 16 hr
2 hr 133 days, 8 hr
5 hr 333 days, 8 hr
12 hr 800 days
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Heat Index: A practical measure of how hot the current combination of relative humidity and temperature
feels to a human body. Higher relative humidity makes it seem hotter because our ability to cool
ourselves by evaporating perspiration is reduced.
Humidity Ratio: the ratio between the actual mass of water vapor present in moist air - to the mass
of the dry air.
Reference Pressure: The local barometric pressure. Input to the altitude screen to provide correct
altitude readings. Also known as the altimeter setting.
Relative Humidity: The amount of water vapor actually in the air divided by the maximum amount
of water vapor the air could hold at that temperature, expressed as a percentage.
Station Pressure: The air pressure of your location, NOT reduced to the sea level equivalent.
Temperature: The ambient air temperature.
Wet Bulb Temperature: The lowest temperature to which a thermometer can be cooled by evaporating
water into the air at constant pressure. This measurement is a holdover from the use of an instrument
called a sling psychrometer. To measure wet bulb temperature with a sling psychrometer, a
thermometer with a wet cloth covering over the bulb is spun rapidly through the air. If the relative
humidity is high, there will be little evaporative cooling and the wet bulb temperature will be quite
close to the ambient temperature. Some exercise physiology guides use wet bulb temperature, rather
than heat index, as a measure of the safety of exercise in hot and humid conditions.
Wind Chill: The cooling effect of combining wind and temperature. The wind chill gives a more
accurate reading of how cold it really feels to the human body. The Kestrel wind chill is based on the
National Weather Service standards as of November 1, 2001.

Instruction Manual for Kestrel 4200 version: 4.18
Please register your Kestrel at www.KestrelInstruments.com
Kestrel® Pocket Air Flow Trackers
are designed and manufactured in the USA by:
NIELSEN-KELLERMAN
610.447.1555
www.kestrelinstruments.com
[email protected]
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Calibrations, Certifications and Service
Every NK product is tested and calibrated before it leaves our factory. We guarantee that it will
perform within specifications when you receive it. Each Kestrel comes with a Certificate of Conformity,
with the stated specifications for that product on the back. If you feel an NK product is not meeting
specs when you receive it, call us and we'll make sure you are operating it correctly. If it still appears
that it may be out of spec, return it to us within 30 days of purchase and we will test and recalibrate
all values at no charge. Beyond 30 days, we offer reasonably-priced tests, calibration services and
N.I.S.T. certified calibrations as well as Kestrel tune-ups.
All of our measurements are traceable to the National Institute of Standards and Technology,
ensuring the highest level of accuracy. Our primary Calibration Standards are sent for calibration in
accordance with N.I.S.T. requirements and based on a regular schedule. Only approved laboratories
and N.I.S.T themselves are used for these calibration services. Incoming and outgoing data is
supplied with the certificate of calibration.
We also offer full factory service on every product we manufacture for as long as we make the
product (and as long after as component availability permits). If we can't repair a product, we will
offer you a brand-new replacement under our Customer Care Program (even for accidental damage
and misuse). Visit www.kestrelinstruments.com for more information and pricing for these services.
We request that you contact NK if you feel your product is not working properly. We can often
solve product issues by phone or e-mail, saving you the time and expense of returning the unit. If
we require the product to be returned, we will issue a Return Authorization to expedite the
handling of your claim.
Lifetime Customer Care Warranty
NK wants you to be an NK customer for life, so we take care of you even beyond the terms of the
above warranty with our Customer Care Program. Trade-in any Kestrel Pocket Air Flow Tracker, no
matter the age or condition, and receive a generous discount on the replacement product (same
model only). Our Customer Care Program applies only as long as we manufacture the product, and
does not cover product upgrades.
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Kestrel Pocket Air Flow Trackers Warranty
NK does not believe in "disposable electronics." We know that Kestrel Meters don't typically lead
pampered lives, and we design them for years of performance in tough conditions. Every Kestrel is
designed and manufactured at NK’s facility in Boothwyn, PA. We guarantee every Kestrel Pocket Air
Flow Tracker to be free of defects in materials and workmanship for a period of TWO YEARS from
your date of purchase. We will repair or replace any defective product or part when notified within
the warranty period, and will return the product via domestic ground shipping at no charge.
Additionally, each Kestrel has a 30-day money back guarantee.
The following issues do not result from a manufacturing defect and are not covered under this
warranty: damage due to improper use or neglect (including corrosion), impact damage, modifications
or attempted repairs by someone other than an authorized NK repair agent, impeller failure not
caused by a manufacturing defect, normal wear from use of the product, failed batteries, and re-
calibration beyond 30 days from your date of purchase.
Your warranty period will be measured from your date of purchase. The best way to ensure full
warranty coverage is to REGISTER your NK product promptly on our website: www.kestrelweather.com.
We keep your registration information strictly confidential and do not sell it, share it, or use it for
anything but product-related information bulletins (which you may decline receiving). If you do not
register and cannot provide proof of purchase, your warranty period will be measured from our
date of manufacture, determined by serial number.
We request that you contact NK if you feel your product is not working properly. We can often solve
product issues by phone or e-mail, saving you the time and expense of returning the unit. If we
require the product to be returned, we will issue a Return Authorization to expedite the handling of
your warranty claim.
The Kestrel 4200 is covered by the following patents: 5,783,753, 5,939,645, 6,257,074, and 7,059,170.
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Stored data may be uploaded to a PC with the optional Kestrel PC Interface, NK part number 0804.
SETTING FACTORY DEFAULT
Automatic Data Store On
Data Store Rate 1 hour
Data Overwrite On
Manual Data Store On
User Screen 1 wind speed, temperature, humidity
User Screen 2 humidity, dewpoint, wet bulb
User Screen 3 pressure, altitude, density altitude
Display Contrast 1 0
Automatic Shutdown 15 minutes
Language English
UNIT METRIC IMPERIAL
Wind Functions m/s mph
Temperature Functions °C °F
Barometric Pressure hPa inHg
Altitude Functions m ft
Time Format 24 hour 12 hour
Date Format day/month/year month/day/year