407119A Datasheet, PDF (6/12 Pages) Extech Instruments Corporation. – Heavy Duty Hot Wire CFM Thermo-Anemometer

Air Velocity Measurements
1. Follow the Initialization and Zeroing procedures above before continuing.
2. Open the antenna to the desired length.
3. Slide the air velocity sensor cover down.
4. Press the POWER button to turn the meter on.
5. Place the sensor in the air
current to be measured.
Have the air flow meet the
sensor head in the
direction of the white dot
(as shown in diagram).
6. View the air velocity and temperature readings on the LCD Display. The large main
LCD display shows the Air Velocity reading. The lower LCD sub-display shows the
temperature reading (left) and the unit of measure (right).
7. To turn the meter off, press and hold the POWER button until the meter switches off.
Air Flow (Volume) Measurements (CMM / CFM)
NOTE: Temperature is not displayed while the meter is in the Air Flow mode.
1. Follow the steps in the Initialization and Zeroing section before continuing.
2. Select the air flow mode using the Function button. The LCD will display CMM (cubic
meters per minute) or CFM (cubic feet per minute) when Air Flow is selected.
3. Press the UNIT button momentarily to select the desired air flow units: CMM or CFM.
The LCD display will reflect the selection.
4. Calculate the area of the duct or vent under test (refer to the Useful Conversions and
Equations section in the back of this manual for assistance). Be sure to compute the
area of the vent or duct in square feet or meters. If you have the area in inches, convert
inches to feet before programming the meter with the area value.
5. Press the AREA SET button to begin entering the area in m² or ft². The left digit will
begin flashing. Follow the steps below to enter the area of the duct or vent in question:
Use the ► button to select a digit to change (digit will flash)
Use the ▲ button increase the value of the flashing digit
Use the ▼ button to decrease the value of the flashing digit
6. Press the REC/Enter button and then the AREA SET button to save the new area
value
7. After the area has been entered, the new area value will be shown on the lower left of
the LCD display in ft² or m². If the unit of measure is CFM, the area will be shown in
square feet. If the unit of measure is CMM, the area will be shown in meters squared.
8. Press the ESC button to abort the programming at any time.
9. Place the probe in the area under test. The main LCD digits will indicate the air flow in
CFM or CMM. If the CFM or CMM reading exceeds 99999, use the displayed X10
multiplier to calculate the reading.
10. To turn the meter off, press and hold the POWER button until the meter switches off.
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Model 407119A Version 5.0 October 2005