Tongdy CO2 Monitor with Relay

Tongdy CO2 Monitor with Relay - CO2 Meter
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The Tongdy CO2 Monitor lets you simply and easily monitor and control indoor air quality. Use it to visually monitor air quality with its easy-to-read colored LEDs that quickly change from green to yellow to red as indoor air quality changes. When air quality gets too poor, its built-in relay can be used to turn on ventilation to bring in fresh, outdoor air.

  • Real-time Carbon Dioxide Level Control & Monitor
  • Six Colored LEDs to Easily Check Indoor IAQ
  • Built-in Relay to Control Ventilation

With its one-button on/off/auto ease of use and industry-standard 24V power requirements, the Tongdy CO2 Monitor with Relay is perfect for homes, offices, meeting rooms, classrooms, or anywhere monitoring and controlling indoor air quality is important for occupant's comfort.


This device will NOT meet requirements for CO2 monitoring in the NBIC, NFPA, or IFC regulations.  The accuracy of the sensor in the TIM10 is not designed for safety situations. Refer to our CO2 Safety Products page for devices that meet your needs.

Call us at (877) 678-4259 toll-free or email us to speak with our technical sales team about purchasing the correct device. 


  • Non-Dispersive Infrared (NDIR)
  • Sampling Method: Diffusion
  • Range: 0 – 2,000 ppm
  • Accuracy: ± 30 ppm ± 3 % of measured value
  • Life Expectancy: > 15 years


  • 1st green light <600ppm
  • 1st and 2nd green lights 600-800ppm
  • 1st yellow light 800-1200ppm
  • 1st and 2nd yellow lights 1200-1400ppm
  • 1st red light 1400-1600ppm
  • 1st and 2nd red lights >1600ppm

Electrical / Mechanical

  • Power Input TON-0007: 24VAC/VDC
  • Power Input TON-0007-WP: 110-220VAC 
  • Output Relay: <240VAC/30VDC 3A Switching Current
  • Output Relay Control: 800ppm to 1500ppm via jumpers
  • Additional Outputs: Use Model TON-0001
  • Housing: PC/ABS fireproof plastic; protection class: IP30
  • Maintenance Interval: No Maintenance Required
  • Dimensions: 100mm (H) × 80mm (W) × 28mm (D) or 2x4" wire box
  • Standard: CE-Approved


  • 1 year - See CO2Meter Terms and Conditions. 
  • Data Sheets

  • Manuals

  • Technical Documents

  • Videos

  • Additional Resources

  • Case Studies

Customer Reviews

Based on 4 reviews
The verdict is not out, yet

I'm not sure if this CO2 meter is working correctly - it reports huge spikes (all leds on, default threshold setting) at times when no CO2 spike could be expected (e.g., no occupancy, ventilation running). I will try to calibrate with another unit and report back.


Love it. Performs exactly as documented

Alex V
If you think you need it then buy it.

Safety first! This thing works very well for automating exhaust to remove CO2. Very important because you can’t smell or sense CO2 to get it out of your workspace. Somewhat complex to setup but worth the safety feature.

Jason Cotton
Good for home

Keeps my house in the desired range for CO2 by running the HRV system using the relay connection. Range is adjustable.

"Easy to install, easy to set up, and easy calibration - just what I was looking for."

- Phillip Farrar
Water Plant Superintendent

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