Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
32
Wiring an outdoor air quality sensor
Part #33ZCSPTCO2LCD-01 (Display model)
Part #33ZCSPTCO2-01 (No display)
An outdoor air quality (OAQ) sensor monitors outside air carbon dioxide levels. The RTU Open uses this
information, in conjunction with a CO
2
sensor, to adjust the outside air dampers to provide proper ventilation. An
OAQ sensor is typically duct-mounted in the outside air stream. Duct installation requires an Aspirator Box
Accessory (Part #33ZCASPCO2).
The sensor has a range of 0–2000 ppm and a linear 4-20 mA output. The CO
2
sensor’s power requirements
exceed what is available at
- 1 and 4. Provide a dedicated 24 Vac transformer or DC power supply.
Wiring specifications
Cable from sensor to controller: If <100 ft (30.5 meters) 22 AWG, unshielded
If >100 ft (30.5 meters) 22 AWG, shielded
Maximum length: 500 feet (152 meters)
To wire the OAQ sensor to the controller
1 Wire the sensor to the controller. See appropriate diagram below.
2 Install a field-supplied dedicated 24 Vac transformer or DC power supply.
3 Apply power and verify sensor readings.
Wiring diagram for #33ZCSPTCO2-01:
Sensor may be terminated at Input 1 or 2.