Protmex PT6508
Protmex PT6508 Digital Temperature Humidity Meter
User Manual
Product Overview
The Protmex PT6508 is a professional dual-display digital temperature and humidity meter designed for accurate environmental measurements. It features high-precision digital sensors, a clear LCD backlight display, and multiple temperature modes including ambient, dew point, and wet bulb temperature. This device is suitable for a wide range of applications, from HVAC and industrial use to agriculture, meteorology, and general home monitoring.

Figure 1: Protmex PT6508 Digital Temperature Humidity Meter and accessories.

Figure 2: Wide range of applications for the PT6508 meter.
Setup
Before first use, ensure the batteries are correctly installed.
- Locate the battery compartment on the back of the device.
- Using a small screwdriver (often included), open the battery compartment cover.
- Insert four (4) AAA batteries, ensuring correct polarity (+/-) as indicated inside the compartment.
- Replace the battery compartment cover and secure it with the screw.
- Press the green power button to turn on the device.
The device is now ready for operation.
Operating Instructions
Familiarize yourself with the buttons and display functions of your PT6508 meter.

Figure 3: Key components and buttons of the PT6508.
- Power On/Off: Press the green power button to turn the device on or off.
- Display Modes: The device displays relative humidity (%RH) and temperature. Press the DP/WB button to cycle through different temperature modes:
- Ambient Temperature: Standard air temperature.
- Dew Point Temperature (DP): The temperature at which air becomes saturated with water vapor, leading to condensation.
- Wet Bulb Temperature (WB): The lowest temperature that can be reached by evaporating water into the air.
- Unit Switching (°C/°F): Press the °C/°F button to switch the temperature unit between Celsius and Fahrenheit.
- Data Hold (H): Press and hold the H button to freeze the current reading on the display. Press again to release.
- Min/Max Hold (MIN/MAX): Press the MIN/MAX button to view the minimum or maximum recorded values since the device was powered on or the function was reset.
- Data Storage (MEM) and Recall (READ):
The PT6508 can store up to 99 sets of data.

Figure 4: Data recording and recall functionality.
- To save a reading, press the MEM button. The display will show a memory location number.
- To recall stored data, press the READ button. Use the DP/WB (up arrow) and °C/°F (down arrow) buttons to navigate through the stored data sets.
- To clear all stored data, press and hold the MEM button until the memory indicator clears.
- Backlight: Press the light bulb icon button to turn the display backlight on or off, improving visibility in low-light conditions.
- Automatic Power-Off: To conserve battery life, the device will automatically shut off after 30 minutes of inactivity.
Maintenance
- Cleaning: Wipe the device with a soft, dry cloth. Do not use abrasive cleaners or solvents. Keep the sensor area clean and free from dust or debris.
- Battery Replacement: When the low battery indicator appears on the display, replace all four AAA batteries promptly to ensure accurate readings and continuous operation.
- Storage: Store the meter in a cool, dry place away from direct sunlight and extreme temperatures. If storing for extended periods, remove the batteries to prevent leakage.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No display or dim display | Low or dead batteries; Incorrect battery installation. | Replace batteries; Check battery polarity. |
| Inaccurate readings | Sensor obstructed or dirty; Extreme environmental conditions; Device not stabilized. | Clean sensor area; Allow device to acclimate to environment for a few minutes; Ensure proper ventilation around sensor. |
| Cannot store data | Memory full. | Clear existing data by holding the MEM button. |
Specifications

Figure 5: Physical dimensions of the PT6508 meter.
| Feature | Detail |
|---|---|
| Model Number | PT6508 Temperature Hygrometer |
| Temperature Range | -4~140°F (-20~60°C) |
| Humidity Range | 0~100%RH |
| Refresh Rate | 0.4 seconds |
| Data Storage | Up to 99 data sets |
| Power Source | 4 x AAA batteries (included) |
| Automatic Shut-off | After 30 minutes of inactivity |
| Product Dimensions | 7.24 x 2.36 x 1.14 inches (18.4 x 6.0 x 2.9 cm) |
| Item Weight | 6.56 ounces (0.41 lbs) |
Warranty and Support
Protmex provides a 12-month quality guarantee for this product. If you encounter any issues or have questions, the Protmex support team is available to respond to your requests within 24 hours.
For further assistance or to explore other Protmex products, please visit the Protmex Store.
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