Carrier RTU OPEN 11-808-427-01 - Manual (Page 32)

Installation
26 RTU Open
Wiring diagram for #33ZCT55/56CO2:
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 J4 - 1 and 4. Provide a dedicated 24 Vac transformer or DC power supply.