User's Guide
Vane Anemometer
Model 451112
• Measures Air Velocity & Temperature
• Degrees C/F switchable
• 6 selectable units of measure
• Data Hold function
Introduction
Congratulations on your purchase of Extech’s Vane Anemometer. This meter is shipped fully
tested and calibrated and, with proper use, will provide years of reliable service.
Specifications
General Specifications
Display
0.7" (18mm) 3-1/2 digit (1999 count) LCD
Measurement m/s (meters per second), km/h (kilometers per hour), ft/min
(feet per minute), knots (nautical miles per hour), Temp. °C/°F
Data hold Freezes present value on display when selected
Sensor Structure Air velocity sensor: Conventional twisted vane arm with
Ambient 32 °F to 122 °F (0 °C to 50 °C); <80%
Power Supply 9V battery (Heavy duty type)
Power Current Approx. 9 mA DC
Weight 12 oz. (325 g) (including battery)
Dimensions Main instrument: 6.6 x 3.2 x1.2" (180 x 72 x 32 mm)
Range Specifications
Measure
m/s 0.4 – 30.0 m/s 0.1 m/s ± (2% + 0.2 m/s)
km/h 1.4 – 108.0 km/ 0.1 km/h ± (2% + 0.6km/hr)
ft/min 80 – 5910 ft/min * 10 ft/min ± (2% + 40 ft/min)
knots 0.8 – 58.3 knots 0.1 knots ± (2% + 0.4 knots)
Temp. 0 to 60oC / 32 to 140oF 0.1oC / 0.1oF 0.8oC / 1.5oF
* Multiply displayed ft/min readings by a factor of 10
balanced, low-friction ball-bearing design
Temperature sensor: Thermister
Sensor Head: Round, 2.8" (72 mm) Dia.
Sensor Cable: 39" (1m) length
Range Resolution Accuracy
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451112 V3.3 1/08
Front Panel Description
1. LCD Display
2. °C/ °F /Airflow selection
3. ON/OFF/Data Hold Switch
4. Airflow unit selection
5. Sensor head
3
5
1
2
4
Operation
1. Move the "OFF/ON/HOLD" switch to the ON position to apply meter power.
2. Select temperature or airflow via the "°C/°F /airflow" switch. The display will
indicate temperature or airflow.
3. Select the air velocity units using the "Airflow Units" switch, airflow will display in
"m/s", "km/h", "ft/min", or "knots" as selected. Note that displayed ft/min readings
must by multiplied by 10.
4. When measuring, the air should be striking the vane on
the side of the vane without the yellow dot (see
diagram).
5. Data Hold: During measurements, moving the
"OFF/ON/HOLD" switch to the "Hold" position will freeze
the displayed value. Move the switch back to "ON" to
cancel the HOLD function.
Battery Replacement
When the display indicates "BAT" (low battery), replace the battery. To replace the battery:
a. Remove rear screw (bottom, center), slide the Battery Cover off, and remove
battery.
b. Replace with 9V battery (heavy duty type) and reinstall the cover and rear screw.
c. Make sure the battery cover is secured after changing the battery.
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451112 V3.3 1/08
Calibration and Repair Services
Extech offers repair and calibration services for the products we sell. Extech also
provides NIST certification for most products. Call the Customer Care Department for
information on calibration services available for this product. Extech recommends that
annual calibrations be performed to verify meter performance and accuracy.
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 to 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 www.extech.com for contact
information. 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.
All rights reserved including the right of reproduction in whole or in part in any form.
Technical Support: Extension 200; E-mail: support@extech.com
Repair & Returns: Extension 210; E-mail: repair@extech.com
Product specifications subject to change without notice
For the latest version of this User Guide, Software updates, and other
up-to-the-minute product information, visit our website: www.extech.com
Extech Instruments Corporation, 285 Bear Hill Road, Waltham, MA 02451
Copyright © 2007 Extech Instruments Corporation
Support line (781) 890-7440
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451112 V3.3 1/08
Useful Equations and Conversions
Area equation for rectangular or square ducts
Height (H)
Width (W)
Area (A) = Width (W) x Height (H)
Area equation for circular ducts
Radius
Cubic equations
CFM (ft3/min) = Air Velocity (ft/min) x Area (ft2)
3
CMM (m
/min) = Air Velocity (m/sec) x Area (m2) x 60
NOTE: Measurements made in inches
must be converted to feet or meters
Unit of Measure Conversion Table
m/s ft/min knots km/h MPH
Area (A) =
Where
6 = 3.14 and r
before using the above formulae.
6 x r
2
2
= radius x
1 m/s 1 196.87 1.944 3.6 2.24
1 ft/min 0.00508 1 0.00987 0.01829 0.01138
1 knot 0.5144 101.27 1 1.8519 1.1523
1 km/h 0.2778 54.69 0.54 1 0.6222
1 MPH 0.4464 87.89 0.8679 1.6071 1
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451112 V3.3 1/08
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