User’s Guide
Model 445815
Introduction
Humidity Alert II
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 (for 60
seconds) and an audible buzzer (for 60 seconds)
A
L
E
R
T
RELATIVE HUMIDITY
MAX
A
L
E
R
T
CC
Temperature
MAX
DEW Point
MAX
Humidity Indicator with Dew Point and Programmable Hi/Lo %RH Alarms
RH ALARM
MAX/MIN
RESET
Calibration
Humidity Mold Alert
445815
Congratulations on your purchase of Extech’s Humidity Alert II
Remote Probe Hygro-Thermometer. Humidity alarms warn when
the %RH exceeds a pre-set HI or LO limit. The remote probe
conveniently mounts on the meter or extends for measurements
in ducts or remote locations. It also features Humidity and
Temperature 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 meter’s sensor into a salt reference bottle or 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.
Meter Description
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Temperature-Humidity Sensor
%RH Display
Dew Point Display
Temperature Display
%RH LED alarm
Max/Min push button
Reset push button
Sensor cable storage
Tilt Stand
Humidity calibration adjust
Temperature units switch (ºF/ºC)
Temperature calibration adjust
Wall hanger
Battery compartment
Audible Alarm ON/Off switch
1
A
L
E
R
T
RELATIVE HUMIDITY
MAX
A
L
E
R
T
2
3
Temperature
MAX
DEW Point
MAX
4
5
Humidity Mold Alert
RH ALARM
MAX/MIN
RESET
6
7
Specifications
Range
o
Temperature -10 to 60 C
o
14 to 140 F
Humidity
Dew Point
Battery
Weight
Dimensions
10% to 99%
o
445815
15 11
Al. On
O
13
C
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
O
Al. Off
F
8
9
14
10
12
-36 to 60 C
+/-2 C. @ 20 C
o
o
o
-32.8 to 140 F
+/-3.6 F @ 68 F
(2) 1.5V 'AAA' cell
6 oz (169g)
Display: 4.3x3.9x0.8” (109x99x20mm)
Probe: 0.57” (14.4mm) Dia.: 1.67”(42.4mm) L
Cable length 18” (457mm)
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.
Note: If subjected to an electrostatic discharge the meter may
malfunction and require the user to perform a reset.
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
EXTECH [ EXTECH INSTRUMENTS CORPORATION. ]
