General Tools General Tools MMD5NP Manual

PINLESS

LCD MOISTURE METER

USER’S MANUAL

MMD5NP

99 Washington Street
Melrose, MA 02176

Phone [phone]
Toll Free 1-800-517-8431

Visit us at www.TestEquipmentDepot.com

Please read this manual carefully and thoroughly before using this product.

TABLE OF CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 2 –4

Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

What’s in the Blister Pack . . . . . . . . . . . . . . . . . . 4

Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . 5

Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . 6

Install Battery . . . . . . . . . . . . . . . . . . . . . . . . . 6

Operating Instructions . . . . . . . . . . . . . . . . . . 6 –7

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Warranty Information . . . . . . . . . . . . . . . . . . . . . . 9

Return for Repair Policy . . . . . . . . . . . . . . . . . . . 10

INTRODUCTION

Thank you for purchasing General Tools & Instruments’
MMD5NP Pinless LCD Moisture Meter. Please read this user’s
manual carefully and thoroughly before using the meter.

The MMD5NP is a non-invasive (pinless) instrument that can
detect moisture up to 3/4 in. (19mm) below the surface of
wood or building material (bricks, wallboard, etc.). The meter
infers the level of moisture from the material’s capacitance,
which the meter reads by measuring its effect on an electric
field it generates every time it is powered on.

The meter exploits two physical phenomena to make its
measurements:

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1. The linear relationship between a solid material’s moisture
level and its dielectric constant—and therefore its
capacitance.

2. The so-called fringe-field effect—the slight spreading of the
electric field produced by current flow between two electrodes
when both electrodes are on the same side of a material.

Behind the back cover of the MMD5NP are two metal plates.
When the meter is powered on, the plates are given small and
opposite charges. The potential difference causes current to
flow, creating a three-dimensional electric field.

When the back of the meter is placed against one side of a
material with moisture on or slightly below its surface, the
increased capacitance of the material distorts the electric
field to an extent that can be sensed (as a change in flux over
the sensing area) and measured. Displayed readings reflect
the average moisture level of the material between its surface
and the electric field’s maximum penetration of 3/4 in.
Moisture closer to the surface has a greater effect on the
reading than moisture at the maximum penetration depth.

The MMD5NP has been calibrated at the factory for use with
wood and building material. Because the capacitance of
wood and the capacitance of building material are affected
differently by moisture, the meter measures their moisture
content on different scales.
A button on the front of the MMD5NP provides a convenient
way to switch between the two materials. Display icons
indicate which material is being tested, as well as whether
the current reading is considered low, medium or high for the
material. Any reading can be held by pushing another front­panel button; this feature makes it possible to make a
measurement in a dark place and display it after bringing the
meter into a lighted area. The meter also is equipped with a

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buzzer whose tone rises with increasing wetness; this feature
makes it easy to detect areas of peak moisture.

The LCD displays measurements of wood’s or a building
material's moisture content as % readings with no accuracy
specification. Despite that shortcoming, relative readings are
useful for quickly comparing the moisture levels of materials,
or the wetness of different areas of the same material. For
example, you can use the meter to locate the source of a
water leak above a ceiling by comparing readings at various
points on it. If the ceiling is level, the point that produces the
highest reading is below the source of the leak.

The MMD5NP is powered by a 9V battery included in the
blister pack.

KEY FEATURES

• Non-invasive/non-destructive measurement technique

• Jumbo display • Wide measurement range

• Intuitive display icons: Low/medium/high moisture content;

wood/building material mode

• Measurement hold function • Audible peak reading alert

• Auto-calibrating • Auto power off

• Low and very low battery warnings

WHAT’S IN THE BLISTER PACK

The MMD5NP comes in a plastic blister pack along with a 9V
battery and this user’s manual.

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