1. Introduction
Thank you for choosing the Ketotek Digital CO2 Meter. This device is designed to monitor indoor air quality by detecting Carbon Dioxide (CO2), TVOC, and HCHO levels, along with displaying ambient temperature and humidity. It features a wide-angle LCD with backlight and a high-precision Swiss Sensirion SCD40 sensor for accurate readings. Please read this manual thoroughly before use to ensure proper operation and to maximize the device's lifespan.
Figure 1: Front view of the Ketotek Digital CO2 Meter
2. Key Features
- Simultaneous display of Time, Alarm Clock, Carbon Dioxide Concentration, Temperature, and Humidity.
- Intuitive Carbon Dioxide icon display for quick status checks.
- 24-hour histogram for mean CO2 concentration history.
- Adjustable three-gear backlight function (High, Medium, Low, Off).
- Low battery indicator for timely power management.
- Selectable 12/24 hour time display.
- Switchable °C /°F temperature unit display.
- Configurable CO2 concentration alarm function to alert users of high levels.
- Supports both Manual Baseline Calibration and Automatic Baseline Calibration for CO2 concentration.
- Records maximum and minimum values for temperature, humidity, and CO2 concentration.
- Equipped with a high-precision Swiss Sensirion SCD40 CO2 sensor for reliable measurements.
3. Setup and Initial Operation
3.1 Package Contents
- 1 x CO2 Detector
- 1 x Charging Cable (DC 5.0V 600mA)
- 1 x User Manual
- 1 x Storage Box
3.2 Powering On the Device
- Insert the batteries (if applicable). Upon battery insertion, all symbols on the display will briefly light up, accompanied by a signal tone. The LCD will show a full display for 2 seconds with beeping, then enter normal display mode.
- Connect the device to a DC 5.0V 600mA power supply using the provided charging cable.
- Once DC power is connected, the screen will initiate a 60-second countdown. This indicates the carbon dioxide detection sensor is preheating. During this preheating phase, CO2-related functions are temporarily disabled, and the screen may show "-----".
- After the preheating countdown, the device will begin displaying CO2, temperature, and humidity readings.
Note: If the DC power supply is not plugged in, all functions related to carbon dioxide will be disabled, and the screen will show "-----". Ensure continuous DC power for CO2 monitoring.
Figure 2: The CO2 meter can be used in various indoor environments such as offices, homes, and classrooms.
4. Operating Instructions
4.1 Display Overview
The wide-angle LCD screen provides a rich display of various air quality parameters and environmental data.
Figure 3: Detailed view of the LCD display and its indicators.
- CO2 Concentration: Main numerical display in PPM.
- CO2 Concentration Alarm: Bell icon indicates alarm status.
- Air Quality Level: Indicated by color-coded segments (Excellent, Good, Medium, Poor) and corresponding text.
- CO2 24h History: Bar graph showing CO2 levels over the last 24 hours.
- Temperature Value: Displays current temperature in °C or °F.
- Humidity Value: Displays current relative humidity.
- Clock: Shows current time in 12h or 24h format.
4.2 Backlight Adjustment
The device features an adjustable backlight. Simply touch the panel to cycle through brightness levels.
Figure 4: Backlight settings: High Bright, Medium Bright, Low Bright, and OFF.
- High Bright: Maximum illumination.
- Medium Bright: Moderate illumination.
- Low Bright: Minimum illumination.
- OFF: Backlight is turned off.
4.3 Temperature Unit Conversion (°C/°F)
Refer to the device's buttons (SET, MEM, ALARM CO2, +, -) to switch between Celsius and Fahrenheit temperature units. Specific button press combinations are usually detailed in the quick start guide or on-screen prompts.
4.4 CO2 Alarm Function
The device can be configured to trigger an alarm when CO2 concentration exceeds a preset threshold. Consult the device's menu or specific button combinations (often involving 'ALARM CO2' or 'SET' buttons) to set or adjust the alarm level.
5. Maintenance and Calibration
5.1 Automatic Baseline Calibration
The CO2 detector is designed to self-calibrate every 7 days to maintain accuracy. This process typically occurs automatically in the background and does not require user intervention.
5.2 Manual Baseline Calibration
You can manually calibrate the CO2 sensor if you suspect inaccurate readings or after prolonged use in a stable environment. It is recommended to perform manual calibration in a fresh air environment (e.g., outdoors) where CO2 levels are known to be around 400 PPM.
Figure 5: Manual Calibration Process.
- In normal display mode, press and hold the "+" button for 2 seconds to enter manual baseline calibration preparation mode.
- The display will show "CAL" (Figure 5, step 2).
- Press the "SET" button to confirm entry into the calibration process (Figure 5, step 3).
- Alternatively, you can press "+" again or wait for 30 seconds without pressing any button to exit the calibration preparation mode.
- The manual baseline calibration process takes approximately 20 minutes. During this operation, you can press the "+" button to exit the calibration in advance.
6. Troubleshooting
7. Specifications
Figure 6: Product Dimensions.
Figure 7: The device is equipped with a high-precision CO2 sensor.
8. Warranty and Support
8.1 Warranty Information
This product comes with a 6-month warranty from the date of purchase.
- If the item is found defective within 3 months of purchase, a replacement will be sent without extra charge, or a refund will be issued upon receipt of the defective item.
- If the item is defective after 3 months but within the 6-month warranty period, you may still return it for a replacement. However, you will be responsible for the extra shipping fee.
8.2 Customer Support
For any inquiries or support needs, please contact our customer service. All emails will be answered within 1 business day. If you do not receive a reply, please re-send your email, and we will respond as soon as possible.
9. User Tips
- For the most accurate readings, place the CO2 meter in a central location within the room, away from direct drafts, windows, or air vents.
- Avoid placing the device near heat sources (e.g., radiators, direct sunlight) or in areas with high humidity, as this can affect sensor performance.
- Regularly check the display for the low battery indicator and ensure the device is connected to power for continuous CO2 monitoring.
- If you notice consistently unusual readings, consider performing a manual baseline calibration in a fresh outdoor environment.
