Dwyer Instruments CDTR-2D4B4 | Carbon Dioxide/RH/Temperature Transmitter | 2000 ppm CO2 range | Duct mount | 4 to 20 mA/0 to (5 or 10) VDC CO2 output | RH outputs & 10 kO Type 2 thermistor temperature output
The Dwyer Instruments CDTR-2D4B4 is a duct mount CO₂, relative humidity and temperature transmitter designed for indoor air quality monitoring and demand-controlled ventilation applications. It measures 0-2000 PPM CO₂ and 0-100% RH, with a 10 kΩ Type II thermistor temperature output.
The transmitter provides universal 4-20 mA, 0-5 VDC or 0-10 VDC outputs for CO₂ and RH and features a NEMA 4X (IP66) duct housing.
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Part Number: CDTR-2D4B4
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Product Overview
The Dwyer CDTR-2D4B4 combines carbon dioxide, relative humidity and temperature measurement in a single duct-mounted transmitter, helping reduce the number of individual sensors required in HVAC and building automation systems.
It provides a 0-2000 PPM CO₂ measurement range and 0-100% RH measurement range, together with a 10 kΩ Type II thermistor temperature output. This combination allows building management and ventilation systems to monitor key indoor environmental conditions through one duct-mounted device.
The transmitter uses a single-beam dual-wavelength NDIR sensor for CO₂ measurement. The sensor automatically corrects the CO₂ measurement for light-source aging in occupied and unoccupied buildings. The CDTR-2D4B4 also supports digital barometric pressure adjustment and field calibration.
Dwyer's Digital Intelligence Temperature Compensation Algorithm (DITCA™) helps eliminate measurement error associated with self-heating in combination sensing devices.
Universal analog outputs for CO₂ and RH can be selected as 4-20 mA, 0-5 VDC or 0-10 VDC, allowing integration with a wide range of building management controllers. The current output supports a maximum 500 Ω load, while voltage outputs require a minimum 500 Ω load.
The humidity and temperature sensors are replaceable, and a physical hardware lockout helps protect configuration settings. The transmitter does not include an integral display, but a service display tool is available for setup and calibration.
The CDTR-2D4B4 is housed in a NEMA 4X (IP66) duct enclosure and supports duct air velocities from 0 to 4000 FPM (20.32 m/s).
Key Benefits
- Measures CO₂, relative humidity and temperature in one duct-mounted device
- 0-2000 PPM CO₂ measurement range
- 0-100% RH measurement range
- 10 kΩ Type II thermistor temperature output
- Single-beam dual-wavelength NDIR CO₂ sensor
- Automatic correction for CO₂ sensor light-source aging
- Digital barometric pressure adjustment and field calibration
- DITCA™ temperature compensation
- Universal 4-20 mA, 0-5 VDC and 0-10 VDC outputs
- Replaceable humidity and temperature sensors
- Physical hardware lockout
- NEMA 4X (IP66) duct housing
- Suitable for demand-controlled ventilation and building automation
- Genuine Dwyer Instruments stock with free UAE-wide shipping
Who This Product Is Best For
The Dwyer CDTR-2D4B4 is suitable for HVAC engineers, facility managers, building automation professionals and system integrators who need CO₂, humidity and temperature measurements from a single duct-mounted transmitter.
Typical applications include demand-controlled ventilation in schools, offices, hospitals and other occupied buildings, as well as indoor air quality monitoring, building management systems and ventilation projects requiring combined CO₂, RH and temperature measurement.
It is also suitable for projects where environmental measurements are required for ventilation control and energy-efficiency monitoring.
How to Specify & Commission It
- Install the CDTR-2D4B4 duct mount transmitter according to the manufacturer's installation requirements.
- Connect the appropriate 16-35 VDC or 19-28 VAC power supply.
- Wire the CO₂ and RH outputs and select 4-20 mA, 0-5 VDC or 0-10 VDC as required.
- Connect the temperature output from the 10 kΩ Type II thermistor to the appropriate controller input.
- Set the required barometric pressure value.
- Perform field calibration if required using the service display tool.
- Verify CO₂, RH and temperature readings at the connected controller before commissioning.
Frequently Asked Questions
What does the Dwyer CDTR-2D4B4 measure?
The CDTR-2D4B4 measures CO₂ from 0-2000 PPM and relative humidity from 0-100% RH, with a 10 kΩ Type II thermistor temperature output.
What type of temperature sensor does the CDTR-2D4B4 use?
It uses a 10 kΩ Type II thermistor for temperature measurement.
What outputs are available?
The transmitter provides universal 4-20 mA, 0-5 VDC or 0-10 VDC outputs for CO₂ and RH.
How accurate is the CDTR-2D4B4?
CO₂ accuracy is ±40 ppm + 3% of reading, while relative humidity accuracy is ±2%.
What type of CO₂ sensor does it use?
The transmitter uses a single-beam, dual-wavelength NDIR sensor with automatic correction for light-source aging.
Does the CDTR-2D4B4 have a display?
No. The transmitter has no integral display. A service display tool is available for setup and calibration.
Does the CDTR-2D4B4 require recalibration?
For buildings occupied 24 hours a day, Dwyer recommends verifying calibration every 6 to 12 months, depending on the application.
What is the enclosure rating?
The duct housing is rated NEMA 4X (IP66).
What power supply does it require?
The transmitter operates from 16-35 VDC or 19-28 VAC. Average power consumption is 2 W, with peak consumption of 3.75 W.
Is genuine stock available with UAE shipping?
Yes. Genuine Dwyer Instruments stock is available through General Tech Services LLC with free UAE-wide shipping. Call +971 6 5436933 for pricing and current availability.
Request a Quote Today
For pricing, availability or technical assistance for the Dwyer CDTR-2D4B4 CO₂/RH/temperature transmitter, contact General Tech Services LLC.
Call: +971 6 5436933
Website: www.generaltechshop.ae
