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Using CO2 to Control Odors in Parking Facilities
Carbon Dioxide Characteristics

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CN7216/CN7232 Controller


  • Enclosed vehicle facility ventilation control for garages 42,000 to 250,000 sq ft.
  • Designed to work with VFD controlled fans but can provide on/off control.
  • Single zone control only.
  • Works with AirTest 4-20 mA gas transmitters (TR2000-CO and TR3210-NO2)
  • CO only or CO and NO2 configuration.


Key Features

  • A versatile PLC based controller that utilizes AirTest proven sequence of operation to maximize energy savings and ensure exceptional garage air quality. The version that works with variable speed drives consistently achieves fan energy savings in excess of 90%.
  • The keypad on the controller provides status indication of sensor readings and the control output and also includes a number of user adjustable parameters including:
    • Time Adjustment
    • 7 day occupancy programming
    • Adjustment of VFD operational parameters
    • Adjustment of of high level averaging period with drives control
    • Settings for high alarm indication and off dead-band
    • Designed to sound alarm on high levels and activate a strobe on a sensor malfunction.
    • Horn And strobe silence
  • Can be ordered for single gas control (CO) or multiple gas control (CO, NO2)
  • Versions that can take input from up to 16 or 32 sensors.
  • System provides power to the sensors.
  • UL50 Rated enclosure.
  • Standard version provides 2, 4-20 Ma VFD signals, options for additional outputs available.
  • Keypad mounted outside the controller.



  • Horn and strobe components available in 110VAC or 24VAC.
  • Phone dialler on system alarm.
  • AirTest offers very competitive pricing on Danfoss VFDs that incorporate a energy meter, allowing tracking of ongoing energy savings of the system. Please ask us for a quote.
  • Enclosure lock.

CN7216 / CN7232 Controller

  • Temp Range: -30 to 140F (-40 to 60C)
  • Power options: 115 VAC, 220 VAC
  • Enclosure size 20"(H) X 16"(W) X 6" (D)
  • Two 4-20mA outputs for VFD control. Option for more outputs available
  • Three 5A relays: 1) High Level Alarm, 2) Controller/Sensor Fault, 3) Factory Configurable
  • Keypad indicates controller status and allows for adjustment of major operating parameters.

Published: April 26, 2013 Last Updated: April 27, 2013