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 20 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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45158-EU-EN V3.3 1/13
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)
Knots (nautical miles
per hour)
m/sec (meters per
second)
ft/min (feet per
minute)
Beaufort force 1 to 17 BF 1 BF ± 1
Temperature -18 to 50oC (0 to 122oF) 0.1oF/C ± 1.8oF (± 1oC)
Relative Humidity 10 to 95% 1% ± 5% RH
Dew Point 0 to 50oC (32 to 122 oF) 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;
Average Mode Choice of 5 or 10 reading averaging (2 second factory
Max and Data Hold
Displays
Sample time 1 reading per second for air velocity and temperature
Water-resistant To 1m(3’)
Operating conditions -15 to 50oC (5 to 122oF) / < 80% RH
Power supply Lithium battery (CR-2032 or equivalent) / 400 hour battery
Dimensions / Weight Instrument: 133 x 70 x 19mm( 5.25 x 2.75 x 0.75”)
1.8 to 100.6 km/h 0.7 km/h ± (3% + 1.4 km/hr)
1.0 to 54.3 knots 0.3 knots ± (3% + 0.6 knots)
0.5 to 28.0 m/s 0.1 m/s ± (3% + 0.2 m/s)
100 to 5500 ft/min 20ft/min ± (3% + 40 ft/min)
Precision thermistor for temperature measurements
default)
Max recalls the highest reading; Data Hold freezes the
display
(1 reading per 15 seconds for humidity with 2 second
updates)
life
Vane: 24mm (1”) diameter /95 g (3 oz)
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.
All EU users are legally bound by the Battery Ordinance
to return all used batteries to community collection points
or wherever batteries / accumulators are sold.
Disposal in household trash or refuse is prohibited.
Disposal:
Follow the valid legal stipulations in respect of
the disposal of the device at the end of its lifecycle
Other Battery Safety Reminders
Never dispose of batteries in a fire. Batteries may explode or
leak.
Never mix battery types. Always install new batteries of the
same type.
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.
3
CFM (ft
/min) = Air Velocity (ft/min) x Area (ft2)
3
CMM (m
/min) = Air Velocity (m/sec) x Area (m2) x 60