Carrier 48TC**16 installation instructions Economizer Controls, Indoor Air Quality CO2 sensor

48TC**16

Economizer Controls

Indoor Air Quality (CO2 sensor) —

The indoor air quality sensor accessory monitors space carbon dioxide (CO2) levels. This information is used to monitor IAQ levels. Several types of sensors are available, for wall mounting in the space or in return duct, with and without LCD display, and in combination with space temperature sensors. Sensors use infrared technology to measure the levels of CO2 present in the space air.

The CO2 sensors are all factory set for a range of 0 to 2000 ppm and a linear mA output of 4 to 20. Refer to the instructions supplied with the CO2 sensor for electrical requirements and terminal locations. See Fig. 54 for typical CO2 sensor wiring schematic.

To accurately monitor the quality of the air in the conditioned air space, locate the sensor near a return-air grille (if present) so it senses the concentration of CO2 leaving the space. The sensor should be mounted in a location to avoid direct breath contact.

Do not mount the IAQ sensor in drafty areas such as near supply ducts, open windows, fans, or over heat sources. Allow at least 3 ft (0.9 m) between the sensor and any corner. Avoid mounting the sensor where it is influenced by the supply air; the sensor gives inaccurate readings if the supply air is blown directly onto the sensor or if the supply air does not have a chance to mix with the room air before it is drawn into the return airstream.

To connect the sensor to the control, identify the positive (4 to 20 mA) and ground (SIG COM) terminals on the sensor. See Fig. 54. Connect the 4-20 mA terminal to terminal TB3-9 and connect the SIG COM terminal to terminal TB3-11. See Fig. 55.

IAQ Sensor

	TB3	PL
SEN	9	J5-5

TB3

COM 11 J5-3

24 VAC

C10284

Fig. 55 - Indoor CO2 Sensor (33ZCSENCO2)

Connections

Refer to Form 33CS-67SI, PremierLink Installation, Start-up, and Configuration Instructions, for detailed configuration information

Outdoor Air Quality Sensor

(PNO 33ZCSENCO2 plus weatherproof enclosure) —

The outdoor air CO2 sensor is designed to monitor carbon dioxide (CO2) levels in the outside ventilation air and interface with the ventilation damper in an HVAC system. The OAQ sensor is packaged with an outdoor cover. See Fig. 56. The outdoor air CO2 sensor must be located in the economizer outside air hood.

H G 24 VAC OR

+ - 24 VDC

+ 0-10VDC

- SIG COM + 4-20mA

NC }ALARM

COM RELAY

NO CONTACTS

2 1 8 7 6 5 4 3 2 1

J3 J4

C08635

COVER REMOVED SIDE VIEW

C07135

Fig. 56 - Outdoor Air Quality Sensor Cover

Wiring the Outdoor Air CO2 Sensor: A dedicated power supply is required for this sensor. A two-wire cable is required to wire the dedicated power supply for the sensor. The two wires should be connected to the power supply and terminals 1 and 2.

Fig. 54 - Indoor/Outdoor Air Quality (CO2) Sensor

(33ZCSENCO2) - Typical Wiring Diagram

Wiring the Indoor Air Quality Sensor: For each sensor, use two 2-conductor 18 AWG (American Wire Gage) twisted-pair cables (unshielded) to connect the separate isolated 24 vac power source to the sensor and to connect the sensor to the control board terminals.

To connect the sensor to the control, identify the positive (4 to 20 mA) and ground (SIG COM) terminals on the OAQ sensor. See Fig. 54. Connect the 4 to 20 mA terminal to the TB3-13 terminal of the 48TC**16. Connect the SIG COM terminal to the TB3-11 terminal of the 48TC**16. See Fig. 57.

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