445703 v2.4 11/19
Big Digit Hygro-Thermometer
Model 445703 - User Manual
INTRODUCTION
Congratulations on your purchase of Extech’s Big Digit Hygro-Thermometer. This professional meter, with proper care,
will provide years of safe reliable service.
OPERATION
1. Open the battery compartment by pushing the cover on the rear of the instrument downward as indicated by the arrow.
Remove the battery safety strip and the protective cover on the LCD display. The instrument is now ready for use.
2. The temperature units can be selected via the switch located on the rear of the instrument.
3. The upper display indicates the temperature in degrees C or F. The lower display indicates relative humidity in %.
4. Displaying the minimum and maximum values.
a. Press the MAX/MIN button. The highest value measured since the Reset button was last pressed appears on the
display.
b. Press the MAX/MIN button again to display the lowest value measured since the Reset button was last pressed.
c. Press the MAX/MIN button again to return to normal display operation.
5. Resetting (clearing) the MAX/MIN memory.
6. Press and hold the RESET button for 1 second while in the MAX/MIN display mode to clear the memory and start
recording new max/min values.
7. The unit can be wall-mounted or placed on a flat surface using the foldout footing.
8. The low battery flag will appear on the display when the battery voltage is low. Replace the battery when this occurs.
SPECIFICATIONS
Temperature
-10 to 60°C
±1.0°C within -10°C to 50°C
14 to 140°F
±1.8°F within 14°F to 122°F
Humidity
10% to 99%
±5% RH within 25% to 85% RH and 0 to 50°C or 32 to 122°F
Battery
One (1) 1.5V 'AAA' cell
Size / Weight
109 x 99 x 20mm (4.3 x 3.9 x 0.78”) /169g (6 oz.)
BATTERY REPLACEMENT
Open the battery compartment by sliding the battery cover on the rear of the instrument downward as indicated by the
arrow. Replace the 1.5V ‘AAA’ battery and replace the cover.
You, as the end user, are legally bound (Battery ordinance) to return all used batteries and accumulators; disposal in the
household garbage is prohibited!
You can hand over your used batteries / accumulators at collection points in your community or wherever batteries / accumulators are sold!
Disposal
: Follow the valid legal stipulations in respect of the disposal of the device at the end of its lifecycle
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
