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  Updated: 13 Nov 2018


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The CDS combines a CO2 and Temperature Sensor in one ingenious package.

The CDS series is designed to simultaneously monitor carbon dioxide (CO2) levels in the air and measure the interior building temperature.

  • Simplify Installation and Maintenance with the Dual Capability of the CDS Series Sensor.

  • Optimize your Ventilation Control Strategy and Save Energy When Deploying the CDS Sensor to Maintain Indoor Air Quality.











How many sensors are required in a typical installation?

Where should they be located?

The number of zones with different occupancy patterns should dictate the number of sensors.

In a small office application for example, it would be ideal to have one sensor in the office space and one in the conference area.

Carbon dioxide distribution in a space is influenced by the same factors that influence temperature distribution.

Much like temperature sensors, placement of CO2 sensors should be based on the zone to be controlled and anticipated loads. (e.g. common prescence of several persons).

For optimum control, there should be a CO2 sensor placed in every location where temperature controls are used.

If an HVAC system is serving a series of zones with similar occupancy patterns, sensors placed in the return air ducting may be appropriate.















Should we use duct or wall mounted sensors?
This depends on the speed of response and accuracy you want for the application.

Wall mounted sensors may have a slightly higher installation cost (due to longer wire runs) but will provide readings closest to actual zone conditions.

A duct mounted sensor may be averaging concentrations from several zones and have a slower response time to occupancy changes.

Can we data-log the CO2 level?
CDD 24S CO2 sensor has dual outputs (0-10Vdc and 4-20mA)

The 0-10 Volts is wired to the economizer controller and the 4-20mA current loop could be used for data-logging through a DDC-system or other data-logger.

What is ventilation control?
Ventilation control is a method of ventilation control, which uses carbon dioxide (CO2) as an indication of occupancy.

By ventilating "on demand" and following actual occupancy patterns versus fixed ventilation rates you can meet outside air requirements at all times while minimizing energy costs. 

Is CO2 a measure of Indoor Quality
ASHRAE 62-1989 states that "Indoor Air Quality shall be considered acceptable if the required rates of acceptable outdoor air in Table 2 are provided for the occupied space".

CO2 is not a direct measure of Indoor Air quality.

It is an excellent measure of effective ventilation (mechanical ventilation plus infiltration).

The higher the CO2 concentration the higher the ventilation.

When indoor CO2 levels are very high (above 1800ppm), ventilation is low (below 7cfm/person) and other contaminants can build up, causing irritation and discomfort.

CDD 24S or CDD24HT



CDD 24







CDD 24L or CDD 24HTL

CDD 24S or CDD24HT

CDD 24L or CDD 24HTL


E-mail: ewert@automatikprodukter.se     

Phone: +46(0)31-287202

Mobile: +46(0)708885298



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