User’s Guide
Hunidity Alert
Model 445814
Introduction
Humidity Alert
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
will appear in the display when the alarm is
alarm icon
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 and an
audible buzzer (for 60 seconds)
A
L
E
R
T
Temperature
MAX
MAX
A
L
E
R
T
DEW Point
MAX
CC
Humidity Indicator with Dew Point and Programmable Hi/Lo %RH Alarms
Calibration
Humidity
Alarm
445814
MAX/MIN
RESET
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.
RH Calibration
1. Insert the meter 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 meter 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.
Meter Description
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Temperature-Humidity Sensor
%RH Display
Dew Point Display
Temperature Display
%RH LED alarm
4
Max/Min push button
5
Reset push button
Audible Alarm ON/Off switch
Tilt Stand
Humidity calibration adjust
Temperature units switch (ºF/ºC)
Temperature calibration adjust
Wall hanger
9
Battery compartment
1
Hunidity Alert
A
L
E
R
T
Temperature
MAX
MAX
A
L
E
R
T
DEW Point
MAX
2
3
6
7
445814
MAX/MIN
Humidity
Alarm
RESET
Specifications
Range
o
Temperature -10 to 60 C
o
14 to 140 F
Humidity
10% to 99%
Dew Point
Battery
Weight
Dimensions
o
8 11
Al. On
O
13
C
Al. Off
O
F
14
12
10
Battery Replacement
The low battery flag will appear on the display when the battery
voltage is low. Replace the battery when this occurs.
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’ batteries and replace the cover.
-36 to 60 C
o
-32.8 to 140 F
(2) 1.5V 'AAA' cell
6 oz (169g)
Display: 4.3x3.9x0.8” (109x99x20mm)
Accuracy
o
o
o
+ 1.0 C within -10 C to 50 C
o
o
o
+ 1.8 F within 14 F to 122 F
+ 4% RH within 25% to 85% RH
o
o
and 0 to 50 C or 32 to 122 F
o
o
+/-2 C. @ 20 C
o
o
+/-3.6 F @ 68 F
Note: If subjected to an electrostatic discharge the meter may
malfunction and require the user to perform a reset.
Copyright © 2009 Extech Instruments Corporation. All rights reserved
including the right of reproduction in whole or in part in any form.
www.extech.com
V3.2 5/09
EXTECH [ EXTECH INSTRUMENTS CORPORATION. ]
