Bryant 581J Indoor/Outdoor Air Quality CO2 Sensor, 33ZCSENCO2 - Typical Wiring Diagram

Connect T-59:The T-59 space sensor requires a separate, isolated power supply of 24 VAC. See Fig. 42 for internal connections at the T-59. Connect the SEN terminal (BLU) to RTU Open J20-1. Connect the COM terminal (BRN) to J20-2. Connect the SET terminal (STO or BLK) to J20-3.

581J

BLK (STO)

BRN (COM)

BLU (SPT)

OR SET SEN

OPB COM- PWR+

J20-3

J20-2SENSOR WIRING

J20-1

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

24 VAC

POWER WIRING

Fig. 43 - Indoor/Outdoor Air Quality (CO2) Sensor

(33ZCSENCO2) - Typical Wiring Diagram

NOTE: Must use a separate isolated transformer.

C10291

Fig. 42 - Space Temperature Sensor Typical Wiring

(33ZCT59SPT)

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. 43 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.

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 sensor. See Fig. 43. Connect the 4-20 mA terminal to RTU Open J4-2 and connect the SIG COM terminal to RTU Open J4-3. See Fig. 44.

IAQ Sensor

SEN J4-2

COM J4-3 24 VAC

C08462

Fig. 44 - RTU Open / Indoor CO2 Sensor

(33ZCSENCO2) Connections

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. 45. The outdoor air CO2 sensor must be located in the economizer outside air hood.

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