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Home > Carbon Dioxide (CO2) > CHTDL Series (CO2/RH/Temp) Duct Sensors

CHTDL Series (CO2/RH/Temp) Duct Sensors

  • LCD with field calibration menu
  • 2000/5000 ppm CO2, 2% RH
  • Integrated set-point relay
  • Field replaceable NDIR CO2 element


  • Controlling ventilation in response to occupancy
  • Facilitating compliance with ASHRAE 62.1 standard for air quality
  • Offices, conference rooms, and public assembly areas


Senva CO2 sensors maximize energy savings by ensuring optimal ventilation. Measuring exhaled CO2 levels ensures air is conditioned only when needed. This unit combines CO2, humidity, and temperature sensing all in one compact device, reducing sensors required, installation labor and provides a cleaner IAQ solution

Product     Price   Quantity
CHTDL Duct CO2/RH/Temp transmitter with set-point relay   $ 645.00


List prices shown; trade pricing appears on orderpad for Senva Trade Accounts.
For qualified trade pricing, please contact us at 866-660-8864.
Oregon has no sales tax.

CO2, humidity, and temperature all in one device...fewer units to buy and install

  • LCD display for easy set up of all parameters
  • Options for complete control including set-point
  • 0-5/10V outputs standard. Thermistors optional

High performance NDIR CO2 with set-point relay

  • Non-dispersive infrared sensing element (NDIR) 
  • Selectable auto-calibration mode returns sensor to baseline values
  • Field replaceable CO2 sensor
  • 2000 or 5000 ppm scale

2% RH Accuracy

  • On-board temperature compensation for rH eliminates temp coefficient errors achieving excellent measurement accuracy, high repeatability and offset stability. 


  • Industry leading 7-year limited warranty/ 2-year RH element, 3-year CO2 element limited warranties
Power Supply   12-30VDC/24VAC, 100mA max.
Outputs CO2, RH, and Temperature Transmitters 3 wire 0-5/0-10V (2) (jumper selectable)
CO2 Type Non-dispersive Infrared (NDIR)
Accuracy ±40ppm, ±3% of reading
Response time 60 seconds to 90% reading
Output update rate 3 seconds
Output scaling 0-2000 ppm (default), 0-5000 ppm (option)
Programmable set point Solid-state output, 1A @ 30VAC/DC, N.O.
Relative Humidity Type Dual RH Temp integrated circuit
Accuracy +/-2% over 10 to 90%RH range
Resolution 0.05%RH
Hysteresis +/-1%RH
Non-Linearity factory linearized <1%RH
Temperature coefficient fully compensated on-board
Response time (3) 30s
Output update rate 2s
Operating range 0 to 100%RH (non-condensing)
Long term drift <0.5%RH per year
Operating conditions (4) -20° C to 60° C @ RH>90%
-20° C to 80° C @ RH=50%
Temperature Scaling 32 to 122° F (0-50° C)
  Accuracy (-20 to 70° C range) <+/-1° C; 0.5° C typ @ 25° C
(transmitter specifications; thermistors optional)  
  3% models, <+/-2° C; 0.5° C typ @ 25° C
  Resolution 0.01° C
  Repeatability +/-0.1° C
  Response time (3) 30s
  Output update rate 2s
  Operating range -40° C to 120° C (sensor only)
LCD Menu Setup Parameters SPH, Setpoint, Hi (On) point) 500ppm to full-scale (700ppm default)
SPL, Setpoint, Lo (Off) point) 400ppm to full-scale-50 (600ppm default)
SCL, Scaling 0-2000ppm or 0-5000ppm
(2000ppm default)
ADJ, Adjustment Offset adjustment +/-250ppm (0 default)
CAL, Calibration mode Automatic mode ON or OFF (default=ON)
RUN, Run mode Displays CO2 in ppm
Operating Environment Temperature 32 to 122F (0 to 50C)
Humidity 0-95% non-condensing
Enclosure Material ABS/Polycarbonate
Dimensions 4.0’ h x 4.4”w x 2.1”d (+6.8” probe)
  1. One side of transformer, secondary is connected to signal common. Dedicated transformer is recommended.
  2. 15-30 VDC/24VAC power supply voltage required for 10V output
  3. Time for reaching 63% of reading at 25° C and 1 m/s airflow
  4. Long term exposures to conditions outside normal range at high humidity may temporarily offset the RH reading (+3%RH after 60 hours.)