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Vaisala GMT220 Carbon Dioxide (CO2) Transmitter

Vaisala GMT220 Carbon Dioxide (CO2) Transmitters measure carbon dioxide in humid environments. The housing is IP65 rated for outdoor installation and can be ordered with an optional local display. Vaisala GMT220 series transmitters incorporate the Vaisala CARBOCAP® Sensor. This patented sensor utilises NDIR (Infra-red) technology for stability and reduced uncertainty of measurement. Suggested calibration intervals (dependant on your application) can be extended to 2 years due to the stability of the Vaisala CARBOCAP CO2 sensor.  All calibration information is held within the probe of the GMT220.  This probe is interchangeable, providing ranges from 0…2000ppm (0.2%) upto 0…20% of CO2.


The shorter probe, GMT221 is for higher (%) concentrations of CO2. The longer GMT222 for lower (ppm) CO2 levels.


Note that Vaisala GMT220 was discontinued in 2019 and replaced with the Vaisala GMP251 CO2 ProbeVaisala GMP252 CO2 Probe and Vaisala Indigo Series 200 TransmittersWe continue to offer service work and spare probes.  For new applications please contact Fluidic for help with instrument selection.



  Features of the Vaisala GMT220 Carbon Dioxide transmitters

  • Vaisala’s silicon based NDIR CARBOCAP sensor
  • IP65 protected against dust and spray water
  • Measurement ranges from 0-2000ppm upto 20% CO2
  • Simple installation
  • Analogue (4-20mA / 0-10V) output
  • 2x Configurable relays


Install base for the the Vaisala GMT220 Carbon Dioxide transmitters include

  • Horticulture and fruit storage
  • Greenhouses and mushroom farming
  • Safety alarming and leakage monitoring
  • Demand controlled ventilation in harsh environments


Vaisala GMT220 transmitters can be ordered with locally attached probe for environmental monitoring or with a remote probe on a cable. Cable length maybe upto 10m factory installed. This allows probes to be installaed in difficult to reach areas, or areas with dangerously high levels of CO2. Probes can be removed from the transmitter body and returned to Fluidic for recalibration. You do not have to send back the full Vaisala GMT220 transmitter body, reducing downtime and maintenance issues.


Fluidic are a recognised partner of Vaisala CEN (Industrial division) for Scotland and the North of England.  Our instrumentation engineers are product trained and able to help with instrument selection within the full range of Vaisala Carbon Dioxide, CO2 instrumentation.  Please call either office for more information (Glasgow 0141 641 5920,  Warrington 01925 572401).


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