1. Introduction
The Extech MO257 is a pinless moisture meter designed for non-invasive measurement of moisture content in various building materials, including wood, wallboard, sheetrock, cardboard, concrete, plaster, and mortar. Its pinless design allows for measurements without causing surface damage. The device features a measurement depth ranging from 0.78 inches (20mm) to 1.6 inches (40mm) below the surface, user-settable alarm levels with audible and visual indicators, and a triple backlit LCD for clear readings.
2. Key Features
- Non-invasive measurement of moisture levels in wood, wallboard, sheetrock, cardboard, concrete, plaster, and mortar.
- Measurement depth from 0.78 inches (20mm) to 1.6 inches (40mm) below the surface.
- Two user-settable alarm levels with an audible beeper and visual (flashing "RISK" or "WET") indicators.
- Triple backlit LCD for enhanced visibility in various lighting conditions.
- Moisture Icons provide a visual reference for low, medium, and high levels of moisture.
- Audible Alert Tone increases in frequency as moisture level rises.
- Data Hold Function to freeze readings on the display for convenient recording.
3. Safety Information
Please read and understand all safety instructions before operating the Extech MO257 moisture meter. Failure to follow these instructions may result in injury or damage to the device.
- Do not attempt to open or modify the meter. There are no user-serviceable parts inside.
- Keep the device away from water and excessive humidity to prevent damage.
- Avoid dropping the meter or subjecting it to strong impacts.
- Store the meter in a dry, cool environment when not in use.
- Dispose of batteries according to local regulations. Do not mix old and new batteries.
4. Product Components
The Extech MO257 Pinless Moisture Meter consists of the main unit and its integrated sensor. Familiarize yourself with the following parts:
- Pinless Sensor Ball: Located at the top of the meter, this spherical sensor is used to detect moisture without penetrating the surface.
- LCD Display: A triple backlit screen that shows moisture readings, alarm indicators, and other operational information.
- Power Button: Used to turn the device on and off.
- Function Buttons: Buttons for setting alarms, adjusting parameters, and activating data hold.
- Battery Compartment: Located on the rear of the device, housing the AA batteries.
5. Setup
5.1. Battery Installation
- Locate the battery compartment cover on the back of the meter.
- Slide the cover downwards to open the compartment.
- Insert three (3) AA batteries, ensuring correct polarity as indicated inside the compartment.
- Replace the battery compartment cover by sliding it upwards until it clicks into place.
5.2. Initial Power On
Press the power button to turn on the meter. The LCD will illuminate, and the device will perform a brief self-test before displaying the ready-to-measure screen.
6. Operating Instructions
6.1. Taking a Measurement
To measure moisture content:
- Ensure the meter is powered on.
- Place the pinless sensor ball flat against the surface of the material you wish to measure. Ensure full contact for accurate readings.
- The moisture reading will be displayed on the LCD. The meter will automatically adjust for different material densities within its measurement range.
- Observe the moisture icons (low, medium, high) and listen for the audible alert tone, which will increase in frequency with higher moisture levels.
6.2. Using the Data Hold Function
Press the "HOLD" button (if available, or refer to specific button on device) to freeze the current reading on the display. Press it again to release the hold and resume live measurements.
6.3. Setting Alarm Levels
The MO257 allows you to set two user-defined alarm levels. Consult the full manual for detailed instructions on navigating the menu to set these thresholds. When the measured moisture exceeds a set alarm level, the meter will provide an audible beep and flash "RISK" or "WET" indicators on the display.
7. Maintenance
7.1. Cleaning
Wipe the meter with a dry, soft cloth. Do not use abrasive cleaners or solvents. Ensure the sensor ball is clean and free of debris for accurate readings.
7.2. Battery Replacement
When the battery indicator appears on the display, replace the batteries as described in Section 5.1. Prompt battery replacement ensures optimal performance and accuracy.
7.3. Storage
If storing the meter for an extended period, remove the batteries to prevent leakage. Store the device in its pouch case in a cool, dry place, away from direct sunlight and extreme temperatures.
8. Troubleshooting
This section addresses common issues you might encounter with your Extech MO257 moisture meter.
| Problem | Possible Cause | Solution |
|---|---|---|
| Meter does not power on. | Dead or incorrectly installed batteries. | Check battery polarity; replace batteries if necessary. |
| Inaccurate or inconsistent readings. | Poor contact with surface; dirty sensor; environmental interference; material outside measurement range. | Ensure full contact with the surface; clean the sensor ball; move away from strong electromagnetic fields; verify material is within specified measurement capabilities. |
| Display is dim or flickering. | Low battery power. | Replace batteries. |
| Audible alarm not working. | Alarm feature disabled or volume too low (if adjustable); moisture level below alarm threshold. | Check alarm settings; ensure moisture level exceeds set threshold. |
If the problem persists after attempting these solutions, please contact Extech customer support for further assistance.
9. Specifications
| Parameter | Value |
|---|---|
| Model Number | MO257 |
| Measurement Type | Pinless, Non-invasive |
| Measurement Depth | 0.78 to 1.6 inches (20 to 40 mm) |
| Power Source | 3 AA batteries (included) |
| Voltage | 4.5 Volts (DC) |
| Product Dimensions | 2.5 x 1.1 x 9.2 inches |
| Item Weight | 10.58 ounces (0.3 Kilograms) |
| Manufacturer | Extech |
| Mounting Type | Surface Mount |
10. Warranty and Support
Extech Instruments products are designed for reliability and performance. For information regarding warranty coverage, technical support, or service, please refer to the official Extech website or contact their customer service department. Keep your purchase receipt as proof of purchase for warranty claims.
For the most up-to-date support information, visit the Extech Store on Amazon or the official Extech Instruments website.
