1. Introduction
The Tenmars TM-402 is a versatile air velocity meter designed for precise measurement of air speed, temperature, and air flow. It is part of the TM-41X series, known for its accuracy and ease of use. Equipped with a 30mm vane, it is ideal for spot measurements at air outlets and for reliably checking air conditions. This manual provides detailed instructions for the setup, operation, and maintenance of your TM-402 meter.
2. Key Features
- 30mm 6-plastic vane for accurate readings.
- Sensitive light air response starting from 0.4 m/s.
- Air flow calculation function.
- Max/Min/Avg measurement modes and data hold function.
- Memory capacity for up to 99 records.
- Memory recall function for reviewing stored data.
- Backlight function for improved visibility in low-light conditions.
- Measures air velocity, air flow, and temperature.
3. Specifications
General Specifications
- Display: 42mm(W) x 33mm(L) Monochrome LCD with backlight
- Battery: 9V (NEDA 1604, IEC 6F22 or JIS 006P)
- Battery Life: Approximately 100 hours of continuous use
- Shutoff Rate Power: 3uA
- Operate Maximum Power: 25mA
- Instrument Dimensions: 130(L) x 56(W) x 38(H) mm
- Instrument Weight: Approximately 160g
- Probe Dimensions: 195(L) x 47(W) x 30(H) mm
- Cable Length: 95cm
- Probe Weight: Approximately 100g
Figure 1: Dimensions of the TM-402 meter.
Electrical Specifications
| Unit | Range | Resolution | Accuracy |
|---|---|---|---|
| m/s | 0.4~20 | 0.1 | ±2%+0.2 |
| Km/hr (Kph) | 1.5~72 | 0.1 | ±2%+0.8 |
| mph | 0.9~44 | 0.1 | ±2%+0.4 |
| Knots (kts) | 0.8~38 | 0.1 | ±2%+0.4 |
| ft/min (fpm) | 79~4000 | 1 | ±2%+40 |
| Beaufort | 1~8 | 1 | -- |
| Unit | Range | Resolution | Accuracy |
|---|---|---|---|
| CMM | 0~9999 | 1 | -- |
| CFM | 0~9999 | 1 | -- |
| Unit | Range | Resolution | Accuracy |
|---|---|---|---|
| °C | -20~60 | 0.1 | ±1℃ |
| °F | -4~140 | 0.1 | ±1.8℉ |
4. Setup
4.1 Battery Installation
- Locate the battery compartment cover on the back of the main unit.
- Slide or unclip the cover to open the compartment.
- Insert a new 9V battery (NEDA 1604, IEC 6F22, or JIS 006P) ensuring correct polarity.
- Replace the battery compartment cover until it clicks securely into place.
Figure 2: Battery compartment on the back of the meter.
4.2 Probe Connection
- Connect the cable from the vane probe to the designated sensor input port on the top of the main meter unit.
- Ensure the connection is firm to prevent intermittent readings.
Figure 3: Tenmars TM-402 meter with the vane probe connected.
5. Operating Instructions
Figure 4: Front panel and button layout of the TM-402 meter.
5.1 Power On/Off
- Press the SET button to turn the meter ON.
- Press and hold the SET button for a few seconds to turn the meter OFF.
5.2 Taking Measurements
- Ensure the probe is securely connected to the main unit.
- Hold the vane probe in the airflow you wish to measure, ensuring the airflow passes through the vane blades.
- The current air velocity and temperature will be displayed on the LCD screen.
Figure 5: Example of the TM-402 being used to measure airflow.
5.3 Unit Selection
- Press the UNIT button to cycle through available measurement units for air velocity (m/s, Km/hr, mph, Knots, ft/min, Beaufort) and temperature (°C, °F).
5.4 Data Hold
- Press the HOLD button to freeze the current reading on the display.
- Press HOLD again to release and resume live measurements.
5.5 Max/Min/Avg Measurements
- Press the MAX/MIN button to display the maximum, minimum, or average recorded values since the meter was powered on or the function was reset.
- Cycle through MAX, MIN, and AVG by pressing the button repeatedly.
5.6 Data Recording and Recall
- To record a reading, press the REC button. The meter can store up to 99 records.
- To recall stored data, press the ESC/REC button. Follow on-screen prompts to navigate through stored records.
5.7 Backlight Function
- The backlight function illuminates the LCD for better viewing in dark environments. Refer to the device's specific button for backlight activation, often integrated with another button or automatic.
6. Maintenance
- Cleaning: Wipe the meter and probe with a soft, dry cloth. Do not use abrasive cleaners or solvents.
- Battery Replacement: Replace the 9V battery when the low battery indicator appears on the display to ensure accurate readings and proper operation.
- Storage: When not in use for extended periods, remove the battery to prevent leakage. Store the device in a cool, dry place, away from direct sunlight and extreme temperatures.
- Vane Care: Handle the vane probe carefully. Avoid dropping it or exposing it to excessive force, as this can damage the delicate blades and affect measurement accuracy.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Meter does not power on. | Dead or incorrectly installed battery. | Check battery polarity or replace with a new 9V battery. |
| Inaccurate readings. | Damaged vane, obstructed airflow, or low battery. | Inspect vane for damage, ensure clear airflow, replace battery if low. |
| Display is dim or unreadable. | Low battery or backlight off. | Replace battery. Activate backlight function. |
| Probe not responding. | Loose connection or damaged cable/vane. | Ensure probe cable is firmly connected. Inspect cable and vane for visible damage. |
8. User Tips
- For the most accurate air velocity readings, ensure the vane is positioned directly in the path of the airflow and is not obstructed.
- When measuring air flow (CMM/CFM), accurately input the duct or vent area into the meter's settings if required, as this directly impacts the calculation.
- Utilize the Max/Min/Avg functions to capture fluctuations in airflow or temperature over time, which can be useful for diagnostics.
- The backlight feature is particularly useful in dimly lit areas like HVAC ducts or crawl spaces.
9. Warranty and Support
The Tenmars TM-402 Air Velocity Meter comes with a 1-year warranty from the date of purchase, covering manufacturing defects. For technical support, warranty claims, or any inquiries, please contact our support team:
- Email: 1962233699@qq.com
- WhatsApp: +8613807408738
Please provide your model number (TM-402) and a detailed description of the issue when contacting support.
