1. Introduction
The AEGTEST AGT-2309 is a compact and portable carbon monoxide (CO) detector designed for continuous monitoring of CO concentrations. It features a high-precision electrochemical sensor for fast and accurate detection, providing essential safety in various environments such as homes, during travel, camping, or driving. This manual provides instructions for proper setup, operation, and maintenance of your device.
2. Important Safety Information
Please read all instructions carefully before using the AGT-2309 detector. Failure to follow these instructions may result in inaccurate readings or device malfunction, potentially leading to serious injury or death. Carbon monoxide is a colorless, odorless gas and can be fatal. This device is intended to detect carbon monoxide gas from any source of combustion. It is not designed to detect smoke, fire, or other gases.
- Ensure the device is preheated in an air environment free of CO for accurate readings.
- External factors such as strong ventilation or air currents may dilute CO concentrations, affecting detection accuracy.
- Do not block the ventilation holes on the device.
- Regularly test the device to ensure proper functionality.
3. Package Contents
Upon unpacking, verify that all items listed below are present and in good condition:
- 1 x AEGTEST AGT-2309 Carbon Monoxide Detector
- 1 x Type-C Charging Cable
- 1 x Lanyard
- 1 x User Manual

Figure 3.1: AGT-2309 detector, lanyard, and Type-C charging cable.
4. Product Overview
The AGT-2309 features a clear display and intuitive controls for ease of use. It incorporates an advanced DDS electrochemical sensor for reliable CO detection.

Figure 4.1: Internal components highlighting the DDS sensor for precision detection.

Figure 4.2: The detector's display showing 0 PPM, indicating no detected carbon monoxide.
5. Setup
5.1 Charging the Device
The AGT-2309 is equipped with a rechargeable Lithium-Ion battery. Before first use, or when the battery indicator is low, charge the device using the provided Type-C cable.
- Connect the Type-C cable to the charging port on the detector.
- Connect the other end of the cable to a standard USB power adapter (not included).
- Charging typically takes 2-3 hours. The battery indicator on the display will show charging status.
A full charge provides up to 15 days (360 hours) of standby time.

Figure 5.1: Type-C charging and extended standby time illustration.
5.2 Attaching the Lanyard and Using the Stand
The detector comes with a lanyard for portability and a built-in stand for versatile placement.
- Lanyard: Thread the provided lanyard through the designated loop on the device for easy carrying or hanging.
- Stand: Extend the integrated stand on the back of the device to place it upright on a flat surface.

Figure 5.2: The AGT-2309 with its stand extended and lanyard attached, illustrating its portability and placement options.
6. Operating Instructions
6.1 Power On/Off
To power on or off the device, press and hold the power button for 3-4 seconds until the progress bar on the screen reaches the end. Release the button to complete the process.
6.2 Understanding the Display and Alerts
The device features a clear display showing CO levels in PPM (parts per million) and battery status. It provides both visual and audible alerts.
- Standby Mode: A green breathing light flashes, indicating normal operation and no detected CO.
- Alarm Mode: When CO levels reach the alarm threshold:
- The breathing light turns red.
- A flame icon appears on the screen.
- An audible alarm sounds at 90 dB, increasing in frequency with rising CO levels.

Figure 6.1: Visual and audible alerts in action, showing a high CO reading and alarm indicators.
6.3 Customizing Alarm Thresholds
The AGT-2309 allows for customizable alarm thresholds within its detection range of 0-1000 PPM. Use the arrow buttons to adjust the desired alarm level (e.g., 24, 50, 100, 200, 500 PPM) and the OK button to confirm your selection.

Figure 6.2: Display showing the range of customizable alarm thresholds.
6.4 Testing Functionality
It is recommended to periodically test the detector's functionality. Ensure the device is preheated in CO-free air before testing.
- Cigarette Smoke Test: Place the ventilation holes of the product close to cigarette smoke, ensuring proximity to avoid gas diffusion. The detector should register CO.
- Sealed Container Test: Burn paper or material completely in a sealed container to create a low-oxygen environment. Immediately after burning, place the ventilation holes of the product close to the container to detect CO.
7. Maintenance
- Cleaning: Wipe the device with a soft, dry cloth. Do not use abrasive cleaners or solvents.
- Battery Care: Recharge the device when the battery indicator is low to maintain optimal performance and extend battery life.
- Storage: Store the detector in a cool, dry place away from direct sunlight and extreme temperatures when not in use for extended periods.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not power on. | Low battery or incorrect power-on procedure. | Charge the device fully. Ensure the power button is held for 3-4 seconds. |
| No CO reading or alarm during test. | Insufficient CO concentration, sensor not preheated, or ventilation issues. | Ensure adequate CO source for testing. Allow device to preheat in CO-free air. Minimize air currents during testing. |
| Alarm sounds frequently without apparent CO source. | False alarm due to other gases or sensor sensitivity. | Move the device to a fresh air environment. If the alarm persists, contact support. |
9. Specifications
| Feature | Detail |
|---|---|
| Sensor Type | Electrochemical (DDS sensor) |
| Detection Range | 0-1000 ppm |
| Response Time | T ≤ 30 seconds (0.3S for high-precision sensor) |
| Alarm Modes | Audible (90 dB, increasing frequency), Visual (Red breathing light, flame icon) |
| Operating Conditions | -4°F to 122°F (-20°C to 50°C), <90% RH (non-condensing) |
| Standby Time | Up to 15 days (360 hours) |
| Charging Time | 2-3 hours (Type-C) |
| Battery Type | 1 Lithium Ion battery (included) |
| Dimensions | 4.8 x 4.13 x 1.65 inches (Package) |
| Weight | 5.6 ounces |
10. Warranty and Support
The AEGTEST AGT-2309 carbon monoxide detector has undergone rigorous quality inspection and factory calibration, with relevant reports issued by nationally certified laboratories. This ensures the product meets high standards for reliability and performance.
For any questions, technical assistance, or support needs, please refer to the contact information provided with your purchase or visit the official AEGTEST website.