Wiring A Supply Air Temperature Sensor - Carrier RTU Open v3 Installation And Startup Manual

Wiring communication
1
Turn off the RTU Open's power.
2
Wire the TruVu™ ET Display's RS485 connector to the <ALCProduct>'s Rnet port, G to Gnd, + to Rnet +, - to
Rnet - using 2-conductor 22 AWG wire with a maximum distance of 500 feet (152 meters).
3
Turn on the RTU Open's power.
For complete TruVu™ ET Display installation instructions, see the TruVu™ ET Display Installation and Start-up
Guide.

Wiring a Supply Air Temperature sensor

Part #33ZCSENSAT
The RTU Open requires a temperature sensor installed in the supply air stream. The Supply Air Temperature (SAT)
sensor is used to properly control the SAT to the maximum and minimum supply air temperature limits, provide
integrated economizer operation, and control the supply fan VFD output, if Fan Control is set to Variable Speed.
Wiring specifications
Cable from sensor to controller:
Maximum length:
RTU Open v3
Installation and Start-up Guide
If <100 ft (30.5 meters)
If >100 ft (30.5 meters)
500 feet (152 meters)
27
Installing the RTU Open
22 AWG, unshielded
22 AWG, shielded
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