Kestrel 4200 Instructions Manual page 5

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 Function Verification
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.
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, The Weather 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.
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
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
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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.
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button to manually store the measurements (see page 9).
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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