MO53-en-GB_V1.0 7/17
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USER MANUAL
Pinless Moisture Meter
Model MO53
Introduction
Thank you for selecting the Extech MO53 Pinless Moisture Meter. The MO53 sensor performs non-
invasive, relative moisture measurements on wood and building materials such as wallboard, sheet
rock, cardboard, plaster, concrete, and mortar. The MO53 also offers auto power off (APO), display
lock (hold), and self-calibration features.
The MO53 is ideal for building restoration projects and applications where moisture detection on
floors and under carpets is critical. The MO53 is also a handy tool for analyzing the effects of water
leakage behind walls and in ceilings.
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
Manual, Product Updates, and Customer Support.
Measurement Considerations
To measure moisture, the MO53 sensor emits and senses low-power electro-magnetic signals. The
displayed reading in percent is an average of the moisture content measured over the entire sensor’s
surface area (40x40mm [1.6x1.6”]) and the maximum depth of penetration (20mm [0.8”]). 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 MO53 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.
Meter Description
1.
LCD Display
2.
Power button
3.
Display Lock/Beeper button
4.
Material Select button
5.
Sensor (back of meter, directly behind LCD)
Note: Battery compartment on rear of meter
Display Description
1.
Moisture Drop icons (one for low moisture, two for medium, and three for high)
2.
Wood mode
3.
Building Material mode
4.
Beeper active icon
5.
Moisture reading
6.
Digital reading in % (relative)
7.
Display Lock mode
8.
Battery status
Button Description
Symbol
Name
Description
Power ON-OFF button
Long press to switch the meter ON or OFF
/
Material Select button
Short press to select wood or building materials
/
Display Lock / Beeper control
Short press locks reading on the display
Long press toggles the Beeper ON/OFF
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