Product Manual
User 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.
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
Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in
parts and workmanship for one year from date of shipment (a six month limited warranty
applies on sensors and cables). If it should become necessary to return the instrument for
service during or beyond the warranty period, contact the Customer Service Department at
(781) 890-7440 ext. 210 for authorization or visit our website at www.extech.com (click on
Contact Extech and go to Service Department to request an RA number). A Return
Authorization (RA) number must be issued before any product is returned to Extech. The
sender is responsible for shipping charges, freight, insurance and proper packaging to prevent
damage in transit. This warranty does not apply to defects resulting from action of the user
such as misuse, improper wiring, operation outside of specification, improper maintenance or
repair, or unauthorized modification. Extech specifically disclaims any implied warranties or
merchantability or fitness for a specific purpose and will not be liable for any direct, indirect,
incidental or consequential damages. Extech's total liability is limited to repair or replacement
of the product. The warranty set forth above is inclusive and no other warranty, whether written
or oral, is expressed or implied.
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)
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 122
o
F (-18 to 50
o
C) 0.1
o
F/C ± 1.8
o
F (± 1
o
C)
Relative Humidity 10 to 95% 1% ± 5% RH
Dew Point 32 to 122
o
F (0 to 50
o
C) 0.1
o
F/C ± 3.6
o
F (2
o
C)
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 122
o
F (-15 to 50
o
C) / < 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 )
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.
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.
CFM (ft
3
/min) = Air Velocity (ft/min) x Area (ft
2
)
CMM (m
3
/min) = Air Velocity (m/sec) x Area (m
2
) x 60
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.
Copyright © 2008 Extech Instruments Corporation.
All rights reserved including the right of reproduction in whole or in part in any form.
V3.0 03/08
Support Hotline (781) 890-7440
Tech support: Ext. 200; Email: support@extech.com
Repair/Returns: Ext. 210; Email: repair@extech.com
Website: www.extech.com