CO2, VOC, Temp & RH Transmitter Duct (CO2TD) 24V

CO2, VOC, Temp & RH Transmitter Duct (CO2TD) 24V

The Flamefast Duct Mounted Carbon Dioxide, VOC (Volatile Organic Compounds), Temperature and Relative Humidity transmitter offers an accurate and cost-effective solution for the HVAC market, with 0-10V outputs for CO2, VOC, Temp and RH Levels (outputs depend on model selection). When both CO2 and VOC levels are being measured, the unit will display/output the higher of the two concentrations as the VOCs are measured in CO2 equivalent for easy interpretation.

With a robust and easy to install flange mounted enclosure, the unit can be mounted in rugged environments with confidence and the hinged front makes installation quick and easy.

Using the built-in Volt Free Contact, the unit can be easily interfaced with Ventilation and Window Control.

The unit offers four user selectable programmes for different applications; two aimed at Ventilation and a further two aimed at Gas Safety. Custom software profiles are also available to control the relay set point and the traffic light changeover levels, based on any combination of CO2, VOCs, Temp & RH (CO2/VOC as default).


View FileCO2TD - CO2, VOC, Temp & RH Transmitter Duct Mount

Key Features

  • 24V AC/DC Power Supply
  • Low power consumption
  • Robust, hinged enclosure
  • Optional digital readout
  • Optional traffic light indication
  • 3x 0-10V outputs (full-scale linear)
  • Volt free contact output
  • Typical 10 year life expectancy
  • Self-calibrating CO2 and VOC sensors
  • 200mm duct probe length

Technical Specification

Power Supply 24V AC/DC ±10%
Power Consumption 50mA Max
CO2 Range (0 - 10V) 0 - 2,000 / 5,000ppm
CO2 Accuracy ±50ppm +3% @ NTP
CO2 Display Resolution 1ppm
CO2 Sensing Method Solid State NDIR
CO2 Response Time (T90) 30 Seconds
CO2 Typical Sensor Life 10 Years
VOC Range (CO2 Equivalent) 400-2,000ppm
VOC Accuracy ±5% @ NTP
VOC Display Resolution 1ppm
VOC Sensor Type Semiconductor
Temp Range (0-10V) 0 - 50°C
Temp Accuracy ±0.3°C @ 20 - 40°C
Temp Display Resolution 0.1°C
RH Range (0-10V) 0 - 100%
RH Accuracy +/-2% @ 20 - 80%
RH Display Resolution 0.1%
VFC Output Rating SPST - 100mA @ 24V Max
Operating Conditions Temp 0°C to 50°C
Humidity 0 to 95% (NC)
Sampling Method Diffusion
Warm-up Time 30 Seconds
IP Rating IP66 (External to duct)
Housing Material Flame Retardant ABS/PC
Approval CE


Height 152 mm
Width 110mm
Depth 50 mm
Probe Length 200 mm

Installer Selectable Options

  • Backlight (Enable/Disable)
  • Traffic Light changeover levels and Volt Free Contact activation
  • Display Options:
    • On standard Model - replace PPM reading with 'CO2'
    • On -H model - remove RH readout

The CO2TD has four factory set user selectable programmes to control the Volt Free Contact. These are as follows:

Program 1 2 3 4
Green - Yellow 1,000 1,000 1,500 1,500
Yellow - Red 1,500 1,500 2,800 2,800
Relay Position N/O N/O N/C N/C
Relay Set Point 1,000 1,500 2,800 4,500
CO2 Range 2,000 2,000 5,000 5,000

Custom programs available on request

Part Numbers & Options / Accessories

Part No Description
CO2TD Duct Mount CO2 Transmitter
CO2TD-H Duct Mount CO2, Temp & RH Transmitter
CO2TD-V Duct Mount CO2 & VOC Transmitter
CO2TD-VH Duct Mount CO2, VOC, Temp & RH Transmitter
-L Adds a Traffic Light LCD to any of the above

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