![IAQ Sensor](/images/new-backgrounds/33923/3392359x1.webp)
50HCQA
To wire the return air enthalpy sensor, perform the following:
1.Use a
2.Connect the
(+)terminal on the enthalpy controller. Connect the BLK wire to
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. 38 for typical CO2 sensor wiring schematic.
To accurately monitor the quality of the air in the conditioned air space, locate the sensor near a
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
To connect the sensor to the control, identify the positive (4 to 20 mA) and ground (SIG COM) terminals on the sensor. See Fig. 38. Connect the
IAQ Sensor
SEN
COM
C08462
Fig. 53 - RTU-MP / 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. 40. The outdoor air CO2 sensor must be located in the economizer outside air hood.
Wiring the Outdoor Air CO2 Sensor — A dedicated power supply is required for this sensor. A
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. 38. Connect the 4 to 20 mA terminal to
OAQ Sensor/RH Sensor
SEN
COM
24 VAC
C08463
Fig. 54 - RTU-MP / Outdoor CO2 Sensor
(33ZCSENCO2) Connections
On 50HCQ units equipped with
The Fire Shutdown Switch configuration, MENU→Config→Inputs→input 5, identifies the normally open status of this input when there is no fire alarm.
Connecting Discrete Inputs —
Filter Status: The filter status accessory is a
Fan Status: The fan status accessory is a
30