MO57-en-GB_V1.0 7/17
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USER MANUAL
Pinless Moisture Meter
Model MO57
Introduction
Thank you for selecting the Extech MO57 Pinless Moisture Meter. The MO57 employs a non-
destructive spherical sensor that safely glides over surfaces to measure the relative moisture in
wood and other building materials (wallboard, sheet rock, cardboard, plaster, concrete, and mortar)
at any angle to a depth of 10.2cm (4”).
To indicate moisture level the MO57 provides a digital reading, audible tones, and ‘moisture droplet’
icons. Audible tones (eight levels of intensity) and droplet icons (1, 2, or 3) increase in proportion to
increased moisture. Additional features include Auto Power OFF and Display Lock (hold).
This meter ships fully tested and calibrated and, with proper use, will provide years of reliable
service. Please visit our website (www.extech.com) to check for the latest version of this User Guide,
Product Updates, and Customer Support.
Measurement Considerations
To measure moisture, the sensor emits and senses low-power electro-magnetic signals. The
displayed reading in percent is an average of the moisture content measured over the measurement
surface area and the maximum depth of penetration (10.2cm [4.0”]). Moisture that is closer to the
surface has a greater effect on the displayed average than the moisture nearer to the maximum
depth of penetration.
Placing the sensor on a surface whose thickness is less than the maximum depth of penetration may
result in unreliable moisture readings; in these cases, you can stack material on top of the measured
surface to increase the thickness.
The MO57 also produces audible tones and ‘moisture droplet’ display icons to indicate moisture
level. The audible tone rate and number of droplets increase as the moisture level increases. When
measuring, keep hand stationary on the meter while holding and moving the meter, as hand
movement can affect the readings.
Meter Description
1.
LCD Display
2.
Power button
3.
Display Lock/Beeper button
4.
Material Select button
5.
Sensor
Note: Battery compartment on rear of meter
Display Description
1.
Droplet icons (1 for low moisture, 2 for medium, and 3 for high)
2.
Wood mode
3.
Building Material mode
4.
Beeper active icon
5.
Moisture reading
6.
Percent moisture unit (relative)
7.
Display Lock mode
8.
Battery status icon
Button Descriptions
Symbol
Button name
Description
Power ON-OFF
Long press to switch the meter ON or OFF
/
Material Select (wood/building
materials)
Short press to toggle material groups
/
Display Lock / Beeper control
Short press locks/unlocks reading on the display
Long press toggles the Beeper ON/OFF
Operation
Powering the Meter
1.
Long press the power button to turn the meter ON/OFF.
2.
The meter emits audible tones and performs a self-calibration upon start-up. Keep the
measurement sensor at least 8 to 10 cm (3 to 4”) from hands and objects during calibration.
The calibration reading must not exceed 0.5. If so, re-calibrate ensuring that hands or other
objects are clear of the sensor. Note: Calibrate the meter whenever moving from one
measurement area to another.
3.
If the battery symbol appears or if the meter does not switch ON, replace the battery.
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