User’s Guide
Model 445814 Humidity Alert
Humidity Indicator with Dew Point and Programmable Hi/Lo %RH Alarms
Introduction
Congratulations on your purchase of Extech’s Humidity Alert Hygro-Thermometer.
Humidity alarms warn when the %RH exceeds a pre-set HI or LO limit. It also
features Humidity and Temperature calibration adjustments. The unit can be wall-
mounted or placed on a flat surface using the fold-out stand. This professional
meter, with proper care, will provide years of safe reliable service.
Meter Description
1. Temperature-Humidity Sensor
2. %RH Display
3. Dew Point Display
4. Temperature Display
5. %RH LED alarm
6. Max/Min push button
7. Reset push button
8. Audible Alarm ON/Off switch
9. Tilt Stand
10. Humidity calibration adjust
11. Temperature units switch (ºF/ºC)
12. Temperature calibration adjust
13. Wall hanger
14. Battery compartment
Cautions
This device is not a toy and must not reach children’s hands. It contains
hazardous objects as well as small parts that the children could swallow. In
case a child swallows any of them, please contact a physician immediately
Do not leave batteries and packing material lying around unattended; they
can be dangerous for children if they use them as toys
In case the device is going to be unused for an extended period of time,
remove the batteries to prevent them from training
Expired or damaged batteries can cause cauterization on contact with the
skin. Always, therefore, use suitable hand gloves in such cases
See that the batteries are not short-circuited. Do not throw batteries into the
fire.
Copyright © 2005 Extech Instruments Corporation. All rights reserved including
the right of reproduction in whole or in part in any form.
www.extech.com
V3.1 10/05
Operation
Preparation for use
Open the battery compartment by pushing the cover on the rear of the
instrument downward as indicated by the arrow. Remove the battery insulating
strip and the protective film cover on the LCD display.
Temperature Units
Select ºF or ºC units using the rear selection switch.
Audible alarm
Select or using the rear selection switch to turn the audible alarm on or
off.
Maximum / Minimum display
1. Press the MAX/MIN button. The highest value measured since the Reset
button was last pressed appears on the display.
2. Press the MAX/MIN button again to display the lowest value measured since
the Reset button was last pressed.
3. Press the MAX/MIN button again to return to normal display operation.
Resetting (clearing) the MAX/MIN memory
1. Press the MAX/MIN button to enter the MAX/MIN mode.
2. Press and hold the RESET button for 1 second to clear the memory and
start recording new max/min values.
Setting the %RH Alarm Limits.
1. Simultaneously Press and HOLD the MAX/MIN and RESET button until “HI”
and the stored HI %RH limit appears flashing.
2. Press the RESET button to set the Hi %RH limit. Hold the button in for rapid
adjustment.
3. Press the Max/Min button. “LO” and the stored LO %RH limit will appear
flashing
4. Press the RESET button to set the LO %RH limit.
5. Press the Max/Min button to turn on or off the alarm. The alarm icon will
appear in the display when the alarm is active.
6. Press and hold the RESET button to save the settings and exit the mode.
Alert
If %RH exceeds the HI limit or goes below the LO limit the alert will be
activated. The alert consist of two flashing ‘ALERT” icons in the upper display,
a flashing red light (for 60 seconds) and an audible buzzer (for 60 seconds)
Calibration
RH Calibration
1. Insert meter’s sensor into a humidity chamber. The reference should be >70%
RH.
2. Check the reading after 1 hour.
3. Adjust the RH calibration pot in ½ turn increments, waiting for the display to
update after each adjustment, until the reading is within the accuracy
specification.
Temperature Calibration
1. Place the sensor in a stabilized environment of approximately 21°C.
2. Check the reading after 1 hour.
3. Adjust the temperature calibration pot in ½ turn increments, waiting for the
display to update after each adjustment, until the reading is within the
accuracy specification.
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 ‘AA’ batteries
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,
gratuitously, at the collection points for our branches 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
Specifications
Range Accuracy
Temperature -10 to 60
o
C
14 to 140
o
F
+ 1.0
o
C within -10
o
C to 50
o
C
+ 1.8
o
F within 14
o
F to 122
o
F
Humidity 10% to 99%
+
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