Extech Instruments 45158 User manual
User's Manual
Model 45158
Mini Hygro Thermo-Anemometer
Introduction
Congratulations on your purchase of Extech’s
Model 45158 Anemometer. The dual display
indicates Air Velocity and Humidity, Dew Point,
Ambient Temperature, or Temperature with
wind-chill factor. With careful use, this meter
will provide years of reliable service.
Specifications
Range Specifications
Measurement Range Resolution Accuracy (% of reading)
MPH (Miles per hour) 1.1 to 62.5 MPH 0.2 MPH ± (3% + 0.4 mph)
km/hr (kilometers per hour) 1.8 to 100.6 km/h 0.7 km/h ± (3% + 1.4 km/hr)
Knots (nautical miles per hour) 1.0 to 54.3 knots 0.3 knots ± (3% + 0.6 knots)
m/sec (meters per second) 0.50 to 28.00 m/s 0.01 m/s ± (3% + 0.2 m/s)
ft/min (feet per minute) 100 to 5500 ft/min 20ft/min ± (3% + 40 ft/min)
Beaufort force 1 to 17 BF 1 BF ± 1
Temperature 0 to 122oF (-18 to 50oC) 0.1oF/C ± 1.8oF (± 1oC)
Relative Humidity 10 to 95% 1% ± 5% RH
Dew Point 32 to 122oF (0 to 50oC) 0.1oF/C ± 3.6oF (2oC)
General Specifications
Display Dual LCD with low battery and multifunction indicators
Sensors Sapphire bearing, non-corrosive vane for air velocity; Precision
thermistor for temperature measurements
Average Mode Choice of 5 or 10 reading averaging (2 second factory default)
Max and Data Hold Displays Max recalls the highest reading; Data Hold freezes the display
Sample time 1 reading per second for air velocity and temperature
(1 reading per 15 seconds for humidity with 2 second updates)
Water-resistant To 3’ (1m)
Operating conditions 5 to 122oF (-15 to 50oC) / < 80% RH
Power supply Lithium battery (CR-2032 or equivalent) / 400 hour battery life
Dimensions / Weight Instrument: 5.25 x 2.75 x 0.75” (133 x 70 x 19mm)
Vane: 1” ( 24mm ) diameter / 3 oz. ( 95 g )
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com
99 Washington Street
Melrose, MA 02176
Phone 781-665-1400
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
Back to the 45158 Product Info Page
Model 45158 - Version 1.8 - May 2003
2
Meter Description
1 Vane impeller
2 Impeller set screw (on rear of meter)
3 Relative Humidity sensor
4 Temperature sensor
5 LCD display
6 ON/OFF, HOLD key
7 UNITS, MODE key
8 Battery compartment (on rear)
9 Tripod mounting hole
10 Lanyard (neckstrap)
Operation
Turning the meter ON and OFF
•Press the ON/OFF/HOLD button to turn the meter ON
•Press and hold the ON/OFF/HOLD buttons for approx. 3 seconds to turn it OFF
•The meter’s Auto Power OFF feature turns the meter OFF after 10 minutes of inactivity
Change the lower display parameter
•With the meter ON, press and hold down the ON/OFF/HOLD button
•While continuing to hold the ON/OFF/HOLD button, press the UNITS/MODE button
repeatedly to step through Temperature (oF/oC), Humidity (RH%), Dew Point (TD), &
Temperature with wind-chill factor (WCI). Note that the center display is Air Velocity.
Change the Air Velocity unit of measure
•Turn the meter OFF. Press and hold down both buttons until the display turns on and
begins blinking then release both buttons
•Press the UNITS/MODE button repeatedly to step through the units (see specs for list)
•After 5 seconds the meter switches back to normal operation mode automatically
Select temperature units (oC or oF)
•Turn the meter OFF first. Press and hold down both buttons until the display turns on
and begins blinking then release the buttons
•Press both buttons momentarily to change temperature units
•After 5 seconds the meter switches back to normal operation mode automatically
Taking Measurements
Position the meter so that the airflow enters the meter vane from the rear of the meter
(opposite side of front panel logo). A tripod mount is located on the bottom of the meter.
Max Hold
•Max Hold represents the highest measurement taken since the meter was turned on
•Press the UNITS/MODE button to display the Max reading (MAX icon appears)
•Press the UNITS/MODE button repeatedly to step through to the normal operating mode
Average mode
•5 or 10 reading averages can be displayed in the Average Mode.
•Press UNITS/MODE 3 times for 5 reading averaging or 4 times for 10 readings
•To exit this mode, press the UNITS/MODE button until the icons on the left disappear
Data Hold
•Data Hold freezes the most recent displayed reading
•Press and hold the ON/OFF/HOLD button to activate Data Hold
•As long as the ON/OFF/HOLD button is held the reading will remain on the LCD
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Support Hotline (781) 890-7440
Website: www.extech.com
CFM Measurements
Measure the area of the duct using the diagrams below for rectangular and circular ducts
(If the duct measurements are made in inches, divide the inches by 144 to get the area in
square feet). Plug the area value (in square feet) in the cubic equations below. Note that
the air velocity must be plugged into the cubic equations also.
Height r
Width
Cubic Equations: CFM (ft3/min) = Air Velocity (ft/min) x Area (ft2)
CMM (m3/min) = Air Velocity (m/sec) x Area (m2) x 60
Maintenance
Battery Replacement
The 45158 has a low battery indicator (battery symbol). Important: Turn the meter off
before opening the battery compartment. Using a coin, turn the battery compartment cover
CLOCKWISE to remove it. Once opened, observe the position of the battery, placing the
new one in the same position. Secure the battery compartment cover and dispose of the
lithium battery in accordance with local, state, or national disposal codes.
Impeller Replacement
•Remove the set screw next to the impeller assembly (on the rear of the meter).
•Twist the impeller assembly counter-clockwise to the OPEN position and remove it.
•Install impeller by inserting & twisting the new impeller assembly clockwise
•Tighten the set screw.
Calibration and Repair Services
Extech offers complete repair and calibration services for all of the products we sell. For
periodic calibration, NIST certification or repair of any Extech product, call customer
service for details on services available. Extech recommends that calibration be performed
on an annual basis to insure calibration integrity.
For rectangular
ducts, multiply the
Height x Width
For circular ducts measure
the radius (r), square the
radius and multiply the
radius by π(3.14)
A = πr2(or A = 3.14 x r x r)
Model 45158 - Version 1.8 - May 2003
4
Unit of Measure Conversion Tables
Units Conversion Table
m/s ft/min Knots km/h MPH
1 m/s = 1196.87 1.944 3.6 2.24
1 ft/min = 0.00508 10.00987 0.01829 0.01138
1 knot = 0.5144 101.27 11.8519 1.1523
1 km/h = 0.2778 54.69 0.54 10.6222
1 MPH = 0.4464 87.89 0.8679 1.6071 1
Beaufort Conversion Table
Beaufort Km / Hour MPH Knots Meter/Sec
0 <1 <1 <1 0-0.2
1 1-5 1-3 1-3 0.3-1.5
2 6-11 4-7 4-6 1.6-3.3
3 12-19 8-12 7-10 3.4-5.4
4 20-28 13-18 11-16 5.5-7.9
5 29-38 19-24 17-21 8.0-10.7
6 39-49 25-31 22-27 10.8-13.8
7 50-61 32-38 28-33 13.9-17.1
8 62-74 39-46 34-40 17.2-20.7
9 75-88 47-54 41-47 20.8-24.4
10 89-102 55-63 48-55 24.5-28.4
11 103-117 64-72 56-63 28.5-32.6
12 to 17 above 117 above 72 above 63 above 32.6
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com
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