1. Introduction
The Testo 625 Digital Hygrometer is a compact instrument designed for precise measurement of air temperature and relative humidity. It also calculates dew point and wet bulb temperature, providing comprehensive data for assessing air quality in various environments, such as storage rooms or offices. Its robust design and long battery life make it suitable for both quick checks and long-term data collection.
2. Package Contents
Verify that all items are present upon unpacking:
- Testo 625 instrument
- Carrying case
- Calibration protocol
- 3 x AA batteries
3. Product Overview
The Testo 625 features a clear display and intuitive controls for easy operation. The integrated probe measures humidity and temperature directly.
Figure 1: Front view of the Testo 625 Digital Hygrometer, showing the display and control buttons.
Figure 2: Dimensions of the Testo 625 Digital Hygrometer, approximately 8.19 inches in height and 2.36 inches in width.
Figure 3: The Testo 625 Digital Hygrometer being used by a person in an indoor environment, demonstrating its portability.
4. Setup
4.1 Battery Installation
- Locate the battery compartment on the rear of the instrument.
- Open the compartment cover.
- Insert the three AA batteries, ensuring correct polarity.
- Close the battery compartment cover securely.
4.2 Powering On/Off
Press the Power button (usually marked with a circle and a vertical line) to turn the device on or off.
5. Operating Instructions
5.1 Basic Measurement
Upon powering on, the Testo 625 will immediately begin measuring air temperature and relative humidity. These values are displayed on the screen.
5.2 Displaying Dew Point and Wet Bulb Temperature
The instrument automatically calculates dew point and wet bulb temperature. Refer to the user interface for specific button presses (e.g., MODE/END or MENU/ENTER) to cycle through display modes and view these calculated values.
5.3 Alarm Function
The Testo 625 includes an audible alarm to indicate when user-defined limit values for humidity or temperature are exceeded. Consult the device's menu options to set or adjust these limits.
6. App Connectivity
The Testo 625 is compatible with the Testo Smart App, which enhances its functionality. The app allows you to:
- View and document measurement results.
- Configure instrument settings.
- Store measured values.
- Use your smartphone as a second display for real-time readings.
Download the Testo Smart App from your device's app store and follow the in-app instructions for pairing with your Testo 625.
7. Specifications
| Parameter | Value |
|---|---|
| Temperature Measuring Range | -20 to +140 °F / -20 to +60 °C |
| Temperature Accuracy | ±0.9 °F / ±0.5 °C |
| Temperature Resolution | 0.1 °F / 0.1 °C |
| Humidity Measuring Range | 0 to 100 %rH |
| Humidity Accuracy | ±2.5 %rH (5 to 95 %rH) |
| Humidity Resolution | 0.1 %rH |
| Weight | 7 oz. / 199 g |
| Dimensions (Instrument) | 8.19 x 2.36 x 1.10 in. / 208 x 60 x 28 mm |
| Operating Temperature (Instrument) | -4 to +122 °F / -20 to +50 °C |
| Operating Temperature (Probe) | -4 to +158 °F / -20 to +70 °C |
| Housing Material | ABS + PC / TPE |
| Protection Class | IP40, IP20 |
| Battery Type | 3x AA (Alkaline) |
| Battery Life | 100 hours |
| Storage Temperature | -4 to +122 °F / -20 to +50 °C |
8. Maintenance
8.1 Cleaning
Clean the instrument housing with a damp cloth. Do not use abrasive cleaners or solvents. Ensure no moisture enters the sensor area.
8.2 Battery Replacement
When the battery indicator appears on the display, replace the batteries as described in Section 4.1. Use only AA alkaline batteries.
8.3 Calibration
The Testo 625 comes with a calibration protocol. Regular calibration is recommended to ensure continued accuracy. Refer to Testo's official guidelines or contact their service department for calibration procedures.
9. Troubleshooting
9.1 Device Not Powering On
- Check if the batteries are inserted correctly with the proper polarity.
- Ensure the batteries are not depleted. Replace them if necessary.
9.2 Inaccurate Readings
- Allow the instrument to stabilize in the measurement environment for a few minutes.
- Ensure the sensor is clean and free from obstructions.
- Consider if calibration is due.
9.3 App Connection Issues
- Ensure Bluetooth is enabled on your smartphone/tablet.
- Make sure the Testo 625 is within range of your device.
- Restart both the instrument and the Testo Smart App.
10. Warranty and Support
For detailed warranty information, please refer to the documentation included with your product or visit the official Testo website. For technical support, service, or spare parts, please contact Testo customer service directly. Contact information can typically be found on the Testo website or in the product packaging.
