1. Introduction
The Extech 445703 is a Big Digit Hygro-Thermometer designed for indoor use. It provides simultaneous display of humidity and temperature, featuring large, easy-to-read digits. This device is suitable for monitoring environmental conditions in various indoor settings such as homes, offices, greenhouses, and baby rooms. It includes a Min/Max function to track extreme readings and comes complete with necessary accessories for immediate use.
2. Features
- Large LCD with 1-inch digits for clear visibility.
- Simultaneous display of relative humidity and ambient temperature.
- Measures humidity from 10% to 99% RH.
- Measures temperature from 14°F to 140°F (-10°C to 60°C).
- Accuracy: ±5% RH and ±1.8°F (±1°C).
- Minimum/Maximum (Min/Max) function with reset capability.
- Data Hold function to freeze current readings.
- Includes a built-in stand and a wall mounting bracket for versatile placement.
3. Package Contents
Verify that all items are present and in good condition:
- Extech 445703 Big Digit Hygro-Thermometer
- Integrated Stand
- Wall Mounting Bracket
- One (1) AAA Battery
4. Setup
4.1. Battery Installation
- Locate the battery compartment cover on the back of the unit.
- Slide the cover open.
- Insert one (1) AAA battery, observing the correct polarity (+ and -) as indicated inside the compartment.
- Replace the battery compartment cover securely.
4.2. Placement
- Desktop Use: Extend the integrated stand from the back of the unit to place it on a flat surface.
- Wall Mounting: Use the provided wall mounting bracket and appropriate hardware (not included) to secure the unit to a wall. Ensure the chosen location allows for accurate environmental readings, away from direct sunlight, heat sources, or drafts.
5. Operating Instructions
5.1. Display Overview
The large LCD simultaneously shows the current temperature (top display) and relative humidity (bottom display). The unit automatically begins measuring upon battery installation.
- Temperature Display: Shows the current ambient temperature in either Fahrenheit (°F) or Celsius (°C).
- Humidity Display: Shows the current relative humidity in percentage (%).
5.2. Temperature Unit Selection
To switch between Fahrenheit (°F) and Celsius (°C), locate the small switch or button, typically on the back or side of the unit. Press or slide it to select the desired temperature unit.
5.3. Minimum/Maximum (Min/Max) Function
The Min/Max function allows you to view the highest and lowest temperature and humidity readings recorded since the last reset.
- Press the MAX/MIN button once to display the maximum recorded temperature and humidity. The "MAX" indicator will appear on the display.
- Press the MAX/MIN button a second time to display the minimum recorded temperature and humidity. The "MIN" indicator will appear on the display.
- Press the MAX/MIN button a third time to return to the current temperature and humidity display.
5.4. Resetting Min/Max Readings
To clear the recorded Min/Max values and start a new recording cycle:
- While viewing either the MAX or MIN readings, press and hold the RESET button for approximately 3 seconds. The display will briefly show all segments, then return to current readings, indicating the Min/Max memory has been cleared.
6. Maintenance
6.1. Battery Replacement
When the battery power is low, a low battery indicator will appear on the display. Replace the AAA battery as described in the "Battery Installation" section (4.1).
6.2. Cleaning
Clean the meter's casing with a soft, damp cloth. Do not use abrasive cleaners or solvents. Ensure no moisture enters the sensor area or battery compartment.
7. Troubleshooting
- No Display or Faint Display: Check battery polarity. Replace the AAA battery if it is low or depleted.
- Inaccurate Readings: Ensure the meter is placed in a stable environment, away from direct heat, cold, or strong air currents. Allow sufficient time (at least 30 minutes) for the meter to stabilize to the ambient conditions.
- Display Frozen: If the display appears frozen, the Data Hold function might be active. Press the appropriate button (if available, usually labeled "HOLD") to release it. If no such button, remove and reinsert the battery to reset the unit.
8. Specifications
| Parameter | Value |
|---|---|
| Humidity Range | 10 to 99% RH |
| Temperature Range | 14 to 140°F (-10 to 60°C) |
| Humidity Accuracy | ±5% RH |
| Temperature Accuracy | ±1.8°F (±1°C) |
| Display | Large Digit LCD |
| Power Source | 1 x AAA Battery |
| Product Dimensions | 3.9" W x 4.3" H |
| Item Weight | 0.704 ounces (0.02 kg) |
| Mounting Options | Stand, Wall Mount |
9. Warranty and Support
The Extech 445703 Big Digit Indoor Humidity & Temperature Meter comes with a 1-Year Warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use.
For technical support, warranty claims, or service inquiries, please contact Extech customer service directly. Refer to the official Extech website or product packaging for the most current contact information.
