Extech MO220 Operating Manual

User Guide

Moisture Meter

Model MO220

Introduction

Congratulations on your purchase of the Extech MO220 Moisture Meter. This instrument is a conductivity moisture meter specifically designed for the wood industry.

The instrument has eight calibration scales, enabling the user to take accurate moisture measurements in 150 wood species. Moisture measurements can be taken using the integral pin electrodes, or using the heavy duty moisture probe.

When used with the temperature probe, the moisture measurements are automatically corrected with respect to temperature. This meter is shipped fully tested and calibrated and, with proper use, will provide years of reliable service.

Model MO220 V1.1 10/07

Specifications

Display Dual measurement scale LCD with bargraph metering Measurement principle Electrical resistance Range Wood: 6 to 44%, Building materials: 0.2 to 2.0% Electrode length 0.3” (8mm) Electrode pins Integrated, replaceable Auto Power OFF After approx. 15 minutes Power supply Two (2) ‘AAA’ 1’5V batteries Meter housing Impact-proof plastic Operating Temperature 32 to 104 Operating Humidity 85% Relative Humidity maximum Dimensions 5.1 x 1.6 x 1.0” (130 x 40 x 25mm) Weight 3.5 oz. (100g)

F (0 to 40oC)

Description

Meter Description

1. Measurement pins

2. Low battery icon

3. LCD measurement reading

4. Wood group designators

5. Units of measure

6. External moisture sensor input

7. Remote temperature probe jack

8. Temperature units button

9. Wood group letter selector button

10. Power ON-OFF button

Note that the battery compartment is

located on the rear of the instrument.

2 3

6 7

Model MO220 V1.1 10/07

Operation

Basic Measurement Instructions

Manual Temperature Correction (for use without the Temperature Probe)

Automatic Temperature Correction ATC (for use with the Temperature Probe)

Auto Power OFF

CAUTION: The electrode measurement pins are extremely sharp. Use

care when handling this instrument. Cover the pins with the protective cap when the instrument is not in use.

1. Remove the cap to expose the needle electrodes OR connect the heavy duty moisture probe socket on the right hand side of this instrument

2. Switch the meter ON by pressing the

3. Select the appropriate wood calibration scale A, B, C, E, F, G, H or J (see the Wood Calibration Tables later in this guide) using the

4. Push the needle pins or the heavy duty moisture probe pins into the wood and observe the reading.

5. Press and hold

The instrument is calibrated for wood at 68°F (20°C). In general, wood that is warmer than 68°F (20°C) will give higher readings and wood colder than 68°F (20°C) will give lower readings. An approximate manual correction of 0.5% moisture content per 9°F (5°C) may be subtracted from wood that is above 68°F (20°C). For wood that is below 68°F (20°C), a manual correction of 0.5% moisture content per 9°F (5°C) may be added to the measured value.

1. Switch the instrument on and select the appropriate wood calibration scale as detailed earlier.

2. Using a hammer and nail of a nominal 3 mm diameter, make a hole in the wood to be tested.

3. Remove the nail and push the Temperature Probe into the hole until the tip is at the required depth.

4. Connect the Temperature Probe into the instrument via the Temp socket.

5. Measure the wood as described earlier to obtain the automatically temperature corrected (ATC) moisture value.

6. To read the current temperature of the wood press the T button, the LCD will display the temperature.

7. Press the T button again to change the C/F unit of measure.

8. Press the

The meter can automatically turn itself off after several minutes. This is to conserve on battery energy. The user can select the period of time the meter must remain idle before turning itself off (1 through 9 minutes). The user can also elect to disable the automatic power off feature (select 00).

1. With the meter ON, simultaneously press the power and the right arrow

2. While continuing to hold the power button, use the right arrow button to select

3. Release both buttons when the desired value is on the LCD.

the power button to shut the meter off.

button to display moisture value again.

buttons. The current time period will appear.

the desired time period. Select ‘00’ to disable this feature.

button.

Model MO220 V1.1 10/07

Manual Accuracy Check

 There are two (2) sets of calibration poles located inside the meter’s protective cover.

One set is for the 18% calibration and the other is for the 26% calibration, as marked inside the cover.

 When checking the calibration, the A scale should be selected and the temperature

probe must be disconnected.

 Touch the two measurement pins to the 18% calibration nodes and view the

measurement on the meter display. Do the same for the 26% calibration.

 When correctly calibrated, the instrument will register %H2O values in the range of

17.7 to 18.3 (18% calibration) and in the range of 25.5 to 26.5 (26% calibration).

 If the tolerance exceeds ±1 the instrument must be recalibrated.

Care and Maintenance

When the instrument is not in use, keep it in its pouch together with its accessories. Store the kit in a stable, dust-free environment out of direct sunlight. Remove the batteries from the instrument if it is to be stored for periods of more than one month, or when the low battery power symbol appears on the display. Check the condition of accessories used with the instrument on a regular basis and replace them if they become worn or damaged.

Battery replacement

When the low battery icon appears on the display, replace the battery as soon as practical.

1. Remove the rear battery compartment screw.

2. Remove the battery compartment door

3. Replace the two (2) ‘AAA’ 1’5V batteries

4. Replace the compartment door and secure the screw before using the meter.

Model MO220 V1.1 10/07

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