General MM7 User Manual

INTRODUCTION
Thank you for purchasing General Tools & Instruments' MM7
Pin-Type LCD Moisture Meter with Tricolor Bar Graph. Please
read this user's manual carefully and thoroughly before using
the instrument.
The MM7 is designed for use in woodworking, water damage
restoration, building construction and home renovation.
Examples include:
• Checking for moisture and mold on or below the surface of
carpets and subflooring
• Measuring the moisture content of wood, drywall or cement
board before painting, wallpapering, sealing or treating
• Locating water leaks above ceilings, below floors or behind
walls
• Selecting dry lumber
The MM7 bases its measurements on the relationship between
the moisture content of a material and its electrical conductivity.
The wetter a material, the higher its conductivity.
The two replaceable steel pins at the top of the MM7 serve as
the electrodes of a conductance meter optimized for measuring
moisture content. The meter displays measurements in the unit
%WME (Wood Moisture Equivalent).
For hard materials like wood, the meter's readings largely reflect
surface moisture content because: 1) Moisture close to a surface
has a greater effect on a reading than moisture deep below it;
and 2) The pins of the MM7 are only 0.3 in. (8mm) long and
PIN-TYPE LCD MOISTURE METER
WITH TRICOLOR BAR GRAPH
USER'S MANUAL
therefore cannot be driven deep into a hard material. For softer
materials like soil, paper or powders, readings are more likely to
reflect the average moisture level of the material between its
surface and the penetration depth of the pins (normally far less
than 0.3 in.).
The MODE button on the front panel provides a convenient way
to switch between testing wood and building materials. When
the MM7 is powered on, it automatically enters wood
measurement mode.
Below the LCD is a analog bar graph comprising three banks of
different-colored LEDs. The LEDs light up in sync with changes
in the digital readout.
As the test pins are moved around a sample, or moved among
samples, the color of the right-most "lit" LED (green, orange or
red) may change. Any such change indicates a sizable difference
in the moisture content of different areas of the same sample, or
of different samples of wood or building material.
See the Specifications table on page 3 for the different moisture
ranges of wood and building materials indicated by the three
LED bar graph bands.
To extend battery life in both operating modes, the MM7
automatically 1) dims the brightness of its backlit LCD by
one-half after 15 seconds and 2) powers itself off after 1 minute
of inactivity.
The instrument is powered by a "9V"battery (included in the
package).
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