Model MO280 - Pin-Free Moisture Meter
Introduction
User Guide
Congratulations on your purchase of the Extech MO280 Moisture Meter. This device non-invasively measures and displays moisture content (%) in
wood, building products, and other materials. The MO280 can also detect moisture behind ceramic tiles or behind and under various floor or wall
coverings, on fabric/cloth and on paper products. This professional meter, with proper care, will provide years of safe reliable service.
Theory of Operation
The square sensor on the rear of the instrument sends and receives a low power electromagnetic signal through the material under test. The LCD
shows the average moisture content (in %) of the material under test to a max. depth of ¾” (20mm). Moisture that is closer to the surface of the
material under test has a greater effect on the average than moisture deeper in the material. The MO280 is an auto-calibration device; no user
calibration is needed.
How to use the MO280
1.
2.
3.
4.
5.
6.
Slide the rear power switch to the ON position
IMPORTANT:
Hold the meter up so that the rear sensor is not covered by your hand or any
surface or object. If the meter emits chirping tones, the sensor is entirely or partially covered
Momentarily press the MEASURE button to activate the sensor (the LCD display will switch on)
Press and hold the UP or DOWN button to select a material group 0 to 9 (see table below). When
the desired group is displayed, release the button. The meter will briefly chirp
Firmly press the meter to a smooth flat surface with the sensor side of the meter (back) touching
the material under test and wait for the display to stabilize; Note the value on the LCD.
The meter’s audible tones will sound as the reading changes. A blinking reading with an urgent
chirping sound indicates that the measurement is out of the range of the instrument’s capability.
Try another range by selecting another material group (see material group & range tables below)
Press and hold the HOLD button to freeze a displayed reading
If the meter goes into sleep mode, press the MEASURE button to wake it up. If the meter does not
wake or if the low battery icon appears on the LCD, replace the 9V battery located in the rear
battery compartment
Turn the rear power switch to OFF when meter is not in use. This will optimize the battery life
WARRANTY
EXTECH INSTRUMENTS CORPORATION
warrants this
instrument to be free of defects in parts and workmanship for
one year
from date of shipment (a six month limited warranty
applies to sensors and cables). If it should become necessary
to return the instrument for service during or beyond the
warranty period, contact the Customer Service Department at
(781) 890-7440 ext. 210 for authorization or visit our website
www.extech.com for contact information. A Return Authorization
(RA) number must be issued before any product is returned to
Extech. The sender is responsible for shipping charges, freight,
insurance and proper packaging to prevent damage in transit.
This warranty does not apply to defects resulting from action of
the user such as misuse, improper wiring, operation outside of
specification, improper maintenance or repair, or unauthorized
modification. Extech specifically disclaims any implied
warranties or merchantability or fitness for a specific purpose
and will not be liable for any direct, indirect, incidental or
consequential damages. Extech's total liability is limited to
repair or replacement of the product. The warranty set forth
above is inclusive and no other warranty, whether written or
oral, is expressed or implied.
7.
8.
9.
Measurement Considerations
The thickness of the sample under test must be at least 3/4” (20mm). If the sample is thinner, use a stack of samples to measure. Also, the
measurement area of the sample should be larger than the MO280 sensor area which is 1.6 x 1.6” (40 x 40mm).
Technical information
Wood and Other Material Group Numbers
No.
4
5
6
5
4
5
4
4
6
6
4
3
5
4
3
4
7
5
5
5
4
7
5
5
3
5
4
6
Name
Abachi
Abura
Afrormosia
Agba
Alder
Ash
Aspen
Basswood
Beech
Birch
Cedar, Eastern
Cedar, Western
Cherry
Chestnut
Cottonwood
Cypress
Dogwood
Douglas Fir
Elm
Gum, Red
Hemlock
Hickory
Koa
Lauan, White
Lauan, Red
Larch
Limba
Locust, Black
No.
4
5
5
6
6
6
7
7
4
4
5
4
4
5
4
8
5
4
5
5
6
4
3
3
9
3
9
5
Name
Mahogany
Maple, Bigleaf
Maple, Red
Maple, Sugar
Meranti
Oak Red
Oak, White
Pecan
Pine Eastern White
Ponderosa
Red
Southern Yellow
Poplar
Ramin
Redwood
Rosewood
Sassafras
Spruce
Sycamore
Teak
Walnut, Black
Willow
Cloth
Cotton
Dry wall
Fabric
Paper
Plywood
Measurement ranges at 73 F (23 C)
Group No.
0
1
2
3
4
5
6
7
8
9
Range
23.4 to 79.9%
33.4 to 89.9%
43.4 to 99.9%
6.8 to 63.3%
6.7 to 63.2%
5.4 to 61.9%
3.4 to 59.9%
1.6 to 58.1%
0.4 to 56.9%
0.0 to 56.5%
o
o
Description
2
4
5
3
1
General Specifications
•
•
•
•
•
Max. Measurement depth: ¾” (20mm)
Sensor area 1.6” x 1.6” (40 x 40mm)
Battery type: 9V (rear compartment)
Display: LCD with sleep mode
Operating conditions:
32
º
F to 122
º
F (0
º
C to 50
º
C)
0 to 60%RH (non-condensing)
Meter Dimensions:
2.75 (W) x 5.25 (H) x 1.0 (D)”
(70 x 133 x 25.4mm)
Weight: 5.6 oz (160g) with battery
1. Moisture reading
2. Low battery icon
3. Material group number 0-9
4. Data Hold icon
5. Keypad
Note:
Sensor, battery
compartment, and ON/OFF
switch on reverse side of
meter
•
•
Support line (781) 890-7440
Tech Support: Ext. 200; E-mail: support@extech.com
Repair/Returns: Ext. 210; E-mail: repair@extech.com
Copyright
©
2007 Extech Instruments Corporation
All rights reserved including the right of reproduction in whole or in part in any form.
MO280 V1.1 07/07
EXTECH [ EXTECH INSTRUMENTS CORPORATION. ]
