Carrier RTU Open v3 - Wiring a Supply Air Temperature Sensor

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
27
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: If <100 ft (30.5 meters) 22 AWG, unshielded
If >100 ft (30.5 meters) 22 AWG, shielded
Maximum length: 500 feet (152 meters)