Bryant 551J installation instructions Sen

requirements and terminal locations. See Fig. 47 for typical CO2 sensor wiring schematic.

IAQ Sensor
SEN	J4-2
COM	J4-3
24 VAC
	C08462
Fig. 48 - RTU-MP / Indoor CO2 Sensor
(33ZCSENCO2) Connections

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

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. 49. The outdoor air CO2
sensor must be located in the economizer outside air hood.	551J	j

Fig. 47 - Indoor/Outdoor Air Quality (CO2) Sensor

(33ZCSENCO2) - Typical Wiring Diagram

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. 47. Connect the 4-20 mA terminal to RTU-MP J4-2 and connect the SIG COM terminal to RTU-MP J4-3. See Fig. 48.

COVER REMOVED SIDE VIEW

C07135

Fig. 49 - 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.

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. 47. Connect the 4 to 20 mA terminal to RTU-MP J4-5. Connect the SIG COM terminal to RTU-MP J4-6. See Fig. 50.

OAQ Sensor/RH Sensor

SEN J4-5

COM J4-6

24 VAC

C08463

Fig. 50 - RTU-MP / Outdoor CO2 Sensor

(33ZCSENCO2) Connections

25