Carrier RTU Open v3 Installation manual

R
RT TU U O Op pe en n v v3 3
I
In ns st ta al ll la at ti io on n a an nd d S St ta ar rt t- -u up p G Gu ui id de e
CARRIER CORPORATION ©2019
A member of the United Technologies Corporation family · Stock symbol UTX · Catalog No. 11-808-499-01 · 12/3/2019

Verify that you have the most current version of this document from
www.hvacpartners.com
or your local Carrier
office.
Important changes are listed in
Document revision history
at the end of this document.
CARRIER CORPORATION ©2019. All rights reserved throughout the world. i-Vu is a registered trademark of Carrier
Corporation. All other trademarks are the property of their respective owners.

Contents
Introduction.................................................................................................................................................................. 1
What is the RTU Open controller? ......................................................................................................................1
Specifications ........................................................................................................................................................3
Safety considerations...........................................................................................................................................4
Installing the RTU Open............................................................................................................................................... 5
Field-supplied hardware ......................................................................................................................................5
To mount the RTU Open.......................................................................................................................................6
To wire the controller for power..........................................................................................................................7
To use the rooftop equipment control power transformer.................................................................. 8
To use an auxiliary control power transformer .................................................................................... 9
To set the controller's address......................................................................................................................... 11
To set the controller's communications protocol and baud rate ............................................................... 11
Wiring for communications.............................................................................................................................. 12
Wiring specifications for BACnet MS/TP and ARC156......................................................................12
To wire the controller to the BACnet network ....................................................................................12
Wiring inputs and outputs ................................................................................................................................ 13
Input wiring specifications ..................................................................................................................14
Inputs ...................................................................................................................................................15
Binary outputs .....................................................................................................................................15
Analog outputs ....................................................................................................................................15
To wire inputs and outputs .................................................................................................................16
Wiring sensors and switches to the controller .............................................................................................. 20
Field-supplied sensor hardware .........................................................................................................21
Wiring devices to the RTU Open's Rnet port......................................................................................22
Wiring a Supply Air Temperature sensor............................................................................................27
Wiring a duct air temperature sensor ................................................................................................28
Wiring an outdoor air temperature sensor ........................................................................................29
Wiring a CO2 sensor............................................................................................................................30
Wiring an outdoor air quality sensor ..................................................................................................32
Wiring a relative humidity sensor .......................................................................................................33
Wiring a Humidistat.............................................................................................................................34
Wiring an enthalpy switch...................................................................................................................35
Wiring a status switch.........................................................................................................................37
Wiring a compressor safety ................................................................................................................38
Wiring an occupancy switch or door contact .....................................................................................39
Start-up.......................................................................................................................................................................41
Service Test......................................................................................................................................................... 41
Configuring the RTU Open's properties .......................................................................................................... 43
Sequence of Operation .............................................................................................................................................44
Occupancy........................................................................................................................................................... 44
Supply fan ........................................................................................................................................................... 45
Cooling................................................................................................................................................................. 45
Economizer ......................................................................................................................................................... 46
Power Exhaust.................................................................................................................................................... 47
Pre-Occupancy Purge........................................................................................................................................ 48
Unoccupied Free Cooling .................................................................................................................................. 48
Optimal Start ...................................................................................................................................................... 48
Enthalpy control ................................................................................................................................................. 50
Indoor Air CO2 .................................................................................................................................................... 50
Heating ................................................................................................................................................................ 51
Heat Pump operation........................................................................................................................................ 51
Dehumidification ............................................................................................................................................... 52

Contents
Demand Limiting ............................................................................................................................................... 52
Door switch ......................................................................................................................................................... 52
Remote Occupancy ........................................................................................................................................... 53
Fire Shutdown .................................................................................................................................................... 53
Compressor Safety ............................................................................................................................................ 53
Fan Status........................................................................................................................................................... 53
Filter status......................................................................................................................................................... 54
Alarms ................................................................................................................................................................. 54
Linkage................................................................................................................................................................ 56
Linkage air source mode determination........................................................................................................ 58
Troubleshooting .........................................................................................................................................................59
Communication LED's....................................................................................................................................... 59
To get the serial number .................................................................................................................................. 60
To replace the RTU Open's battery.................................................................................................................. 60
Compliance ................................................................................................................................................................61
FCC Compliance................................................................................................................................................. 61
CE Compliance ................................................................................................................................................... 61
BACnet Compliance........................................................................................................................................... 61
Appendix A: RTU Open Points/Properties in i-Vu®/Field Assistant .....................................................................62
Status................................................................................................................................................................... 62
Unit Configuration.............................................................................................................................................. 63
Setpoints ............................................................................................................................................................. 70
Alarm Configuration .......................................................................................................................................... 76
Service Configuration........................................................................................................................................ 78
Maintenance....................................................................................................................................................... 82
Performance....................................................................................................................................................... 85
Alarms ................................................................................................................................................................. 86
Linkage................................................................................................................................................................ 88
I/O Points............................................................................................................................................................ 89
Appendix B: Single Point Linkage and Device Address Binding............................................................................91
Single Point Linkage ......................................................................................................................................... 91
Device Address Binding .................................................................................................................................... 92
Appendix C: RTU Open Points/Properties on the Equipment Touch ....................................................................93
Navigation screens ............................................................................................................................................ 93
Startup Wizard ................................................................................................................................................... 95
Status - Equipment Touch ................................................................................................................................ 97
Unit Configuration - Equipment Touch............................................................................................................ 98
Setpoints - Equipment Touch.........................................................................................................................100
Alarm Configuration - Equipment Touch......................................................................................................101
Maintenance - Equipment Touch ..................................................................................................................102
Performance - Equipment Touch...................................................................................................................104
Alarms - Equipment Touch .............................................................................................................................104
Document revision history ..................................................................................................................................... 107

RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
1
What is the RTU Open controller?
The RTU Open controller (part# OPN-RTUM2) is available as an integrated component of a Carrier rooftop unit, or
as a field-installed retrofit product.
NOTE
The RTU Open controller is available in both English or Metric units. The metric version has (-M) appended
to the part number. Everything in this document applies to both versions.
Its internal application programming provides optimum rooftop performance and energy efficiency. RTU Open
enables the unit to run in 100% stand-alone control mode or it can communicate to the Building Automation
System (BAS).
The RTU Open supports the following:
•
ZS and Carrier wireless sensors
- Models are available for monitoring space temperature, space relative
humidity, and space IAQ/CO2. Sensors provide:
○Space setpoint offset adjustment
○Pushbutton override
○Occupancy indicator
•
BACnet
and
third party protocols
- On-board DIP switches allow you to select the baud rate and choose one of
the following protocols:
○BACnet MS/TP
○BACnet ARC156
○Modbus
○Johnson N2
○LonWorks
•
Mixed systems
- Supports CCN air terminals using Linkage to BACnet RTU Open Air Source
•
California Title 24
- Includes advanced Fault Detection and Diagnostic Logic for Economizer Operation in
accordance with California Title 24 requirements
•
Equipment Touch
- The Equipment Touch is a user interface that is a touchscreen device with a 4.3 in. color
LCD display that you connect to the RTU Open (driver v6.00:082 or later) to view or change property values,
equipment schedules, trends and alarms, and more, without having to access the system's i-Vu® server.
The RTU Open’s application supports detailed color graphics, status, properties, alarms, trends, performance,
configuration, and Help on the Equipment Touch. In addition, an RTU Open Startup Wizard (page 95) has
specific screens to facilitate initial RTU Open configuration.
For more details about the Equipment Touch, see the Equipment Touch Installation and Setup Guide.
Introduction

Introduction
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
2

Introduction
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
3
Specifications
Driver drv_rtuopn_std
Power 24 Vac ±10%, 50–60 Hz
20 VA power consumption
26 Vdc (25 V min, 30 V max)
Single Class 2 source only, 100 VA or less
Access port
J12
For system start-up and troubleshooting using Field Assistant
Rnet port
J13
•Supports up to 5 wireless and/or ZS sensors, and one Equipment Touch or
TruVu™ ET Display
•Supplies 12 Vdc/210 mA power to the Rnet across its rated temperature
range.
NOTE Ambient temperature and power source fluctuations exceeding the
listed operating ranges may reduce the power supplied by the Rnet port.
NOTE
If the total power required by the sensors on the Rnet exceeds the power
supplied by the Rnet port, use an external power source. The Wireless Adapter,
Equipment Touch, or TruVu™ ET Display must be powered by an external power
source. See the specifications in each device's Installation and Start-up Guide to
determine the power required.
Network Comm port
J19
For communication with the controller network using BACnet ARC156 (156 kbps)
or BACnet MS/TP (9600 bps – 76.8 kbps)
Comm Option port For communication with the LonWorks Option Card.
Inputs 12 inputs:
Inputs 1 - 2: 4-20 mA only
Inputs 3, 5, 8, 9: Binary, 24 Vac
Inputs 6 - 7: Thermistor
Inputs 10 - 11: Thermistor
Rnet sensor
Binary outputs 8 relay outputs, contacts rated at 3 A max @ 24 Vac. Configured normally open.
Analog outputs •AO-1: 2-10 Vdc or 4-20 mA (configurable on jumper J3)
•AO-2: 0-10 Vdc or 2-10 Vdc SC-VFD input
Output resolution 10 bit D/A
Real-time clock Battery-backed real-time clock keeps track of time in event of power failure
Battery 10-year Lithium CR2032 battery retains the following data for a maximum of
10,000 hours during power outages: control programs, editable properties,
schedules, and trends.

Introduction
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
4
Protection Built-in surge and transient protection for power and communications in
compliance with EN61000-6-1.
Incoming power and network connections are protected by non-replaceable
internal solid-state polyswitches that reset themselves when the condition that
causes a fault returns to normal.
The power, network, input, and output connections are also protected against
transient excess voltage/surge events lasting no more than 10 msec.
CAUTION
To protect against large electrical surges on serial EIA-485
networks, place a PROT485 at each place wire enters or exits the building.
Status indicators LEDs indicate status of communications, running, errors, power, and digital
outputs
Environmental operating
range
-40 to 158°F (-40 to 70°C), 10–95% relative humidity, non-condensing
NOTE
Controllers should be mounted in a protective enclosure.
Vibration during operation: all planes/directions, 1.5G @ 20–300 Hz
Shock during operation: all planes/directions, 5G peak, 11 ms
Shock during storage: all planes/directions, 100G peak, 11 ms
Overall dimensions A:
B:
6-1/2 in. (16.5 cm)
6-1/2 in. (16.5 cm)
Mounting dimensions 7 mounting holes in various positions
Depth 1-11/16 in. (4.3 cm)
Weight 11.2 oz (0.32 kg)
BACnet support Conforms to the BACnet Advanced Application Controller (B-AAC) Standard Device
Profile as defined in ANSI/ASHRAE Standard 135-2012 (BACnet) Annex L,
Protocol Revision 9
Listed by UL-873, FCC Part 15-Subpart B-Class A, CE EN50082-1997
Safety considerations
WARNING
Disconnect electrical power to the RTU Open before wiring it. Failure to follow this warning could
cause electrical shock, personal injury, or damage to the controller.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
5
To install the RTU Open:
1 Mount the controller (page 6).
2 Wire the controller for power (page 7).
○To use the rooftop equipment control power transformer (page 8).
○To use an auxiliary control power transformer (page 9).
3 Set the controller's address (page 11).
4 Set the protocol and baud rate (page 11).
5 Wire to the BACnet MS/TP or BACnet ARC156 network (page 12, page 12).
6 Wire inputs and outputs (page 13).
7 Wire sensors to the controller (page 20).
Field-supplied hardware
An RTU Open retrofit installation may require the following field-supplied components:
•wiring harness: Part #OPN-RTUHRN
•transformer – 24 Vac, 20 VA minimum
•wiring
Application-dependent components
:
•carbon dioxide sensors
•damper/damper actuator
•differential pressure switch
•enthalpy switch
•fan status switch
•door switch
•fan section door switch
•relative humidity sensor
•remote occupancy contact
•smoke detector
•temperature sensors
Installing the RTU Open

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
6
To mount the RTU Open
WARNING
When you handle the RTU Open:
•Do not contaminate the printed circuit board with fingerprints, moisture, or any foreign material.
•Do not touch components or leads.
•Handle the board by its edges.
•Isolate from high voltage or electrostatic discharge.
•Ensure that you are properly grounded.
We highly recommend that you mount the RTU Open in the unit control panel!
WARNING
When you mount the RTU Open:
•Do not locate in an area that is exposed to moisture, vibration, dust, or foreign material.
•Follow NEC and local electrical codes.
•Do not obstruct access for unit maintenance.
•Protect from impact or contact during unit maintenance.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
7
Screw the RTU Open into an enclosed panel using the mounting slots on the cover plate. Leave about 2 in. (5 cm)
on each side of the controller for wiring.
To wire the controller for power
CAUTIONS
•The RTU Open is powered by a Class 2 power source. Take appropriate isolation measures when mounting it
in a control panel where non-Class 2 circuits are present.
•Do not power pilot relays from the same transformer that powers the RTU Open.
•Carrier controllers can share a power supply as long as you:
○Maintain the same polarity
○Use the power supply only for Carrier controllers
•The RTU Open has an operating range of 21.6 Vac to 26.4 Vac. If voltage measured at the RTU Open's input
terminals is outside this range, the RTU Open may not work properly.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
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•Avoid running communication wires or sensor input wires next to AC power wires or the controller's relay
output wires. The resulting noise can affect signal quality. Common sources of noise are:
○Spark igniters
○Radio transmitters
○Variable speed drives
○Electric motors (> 1hp)
○Generators
○Relays
○Transformers
○Induction heaters
○Large contactors (i.e., motor starters)
○Video display devices
○Lamp dimmers
○Fluorescent lights
•In most cases, the RTU Open will be powered from the control power transformer provided with the rooftop
equipment. If you must use a separate control power transformer, additional precautions must be taken to
ensure that the auxiliary transformer is in-phase with the rooftop equipment’s control power transformer. See
Using an auxiliary control power transformer (page 9).
To use the rooftop equipment control power transformer
1 Remove power from the 24 Vac transformer.
2 Remove connector assembly from RTU Open's
J1
connector.
3 If the rooftop equipment has thermostat connection terminals, connect wiring harness
J1
wire 1 to R, and
J1
wire 3 to C. Alternately, connect the control power transformer wires to
J1
connector wires 1 (24 Vac) and 3
(Gnd).
4 Apply power to the rooftop equipment.
5 Measure the voltage at the RTU Open’s
J1
terminals 1 and 3 to verify that the voltage is within the operating
range of 21.6–26.4 Vac.
6 Attach harness to RTU Open connector
J1
.
NOTE
The harness and connector are keyed and must be oriented properly for correct installation.
7 Verify that the
Power
LED is on and the
Run
LED is blinking.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
9
To use an auxiliary control power transformer
If you use a separate control power transformer, it is essential that the auxiliary transformer and the rooftop
transformer are in-phase. You
must
verify this prior to connecting the auxiliary transformer to the RTU Open.
Follow these steps:
1 Verify the available primary voltage at the rooftop equipment.
2 Remove power from the rooftop equipment and install the appropriate auxiliary transformer. Follow the
manufacturer’s installation instructions.
3 Ground one leg of the auxiliary transformer’s secondary wiring.
4 Apply power to the rooftop equipment. Measure the potential between the rooftop equipment control power
and auxiliary transformer's secondary hot (non-grounded) legs. If the voltage measured is less than 5 volts,
the transformers are in-phase; proceed to step 7. If you measure a voltage greater than 24 Vac, then the
phases are reversed.
5 Correct the phase reversal by either of the following methods:
○Remove the ground from the secondary at the auxiliary transformer and connect it to the other
secondary
○Reverse the primary wiring at the auxiliary transformer
6 Repeat step 4 to rewire.
7 Remove connector assembly from RTU Open's
J1
connector.
8 Connect the auxiliary transformer wires to
J1
wires
1
(24 Vac) and
3
(Gnd).
9 Apply power to the transformer.
10 Measure the voltage at the RTU Open’s
J1
-
1
and
3
to verify that the voltage is within the operating range of
21.6–26.4 Vac.
11 Attach harness to RTU Open's connector
J1
. See illustration below.
NOTE
The harness connectors are keyed and must be oriented properly for correct installation.
12 Verify that the
Power
LED is on and the
Run
LED is blinking.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
10
Optional
* Safety chain devices, field-installed - normally closed. Apply 24 Vac to this terminal (jumper from
J1
- 1 to
J1
- 9) where no safety devices are installed.
** Fire shutdown device, field-installed, configurable as normally open or closed
*** Enthalpy switch, field-installed - configurable as normally open or closed

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
11
To set the controller's address
The RTU Open's two rotary switches determine the RTU Open's MAC address when it is placed on an MS/TP
network. The rotary switches define the MAC address portion of the RTU Open's BACnet device instance number,
which is composed of the MS/TP network number and the MAC address. They also set the slave address on a
Modbus or N2 network when less than 100. See the RTU Open Integration Guide for additional information on
integration.
1 Turn
off
the RTU Open's power. The controller reads the address each time you apply power to it.
2 Using the rotary switches, set the
MSB (SW1)
(
10's
) switch to the tens digit of the address, and set the
LSB
(SW2)
(
1's
) switch to the ones digit.
EXAMPLE
To set the RTU Open’s address to 01, point the arrow on the
MSB
(
SW1
) switch to 0 and the arrow
on the
LSB
(
SW2
) switch to 1.
10's 1's
1
3
4
5
2
7
8
9
6
0
1
3
4
5
2
7
8
9
6
0
SW1 SW2
MSB LSB
3 Turn on the RTU Open's power.
CAUTION
The factory default setting is
00
and must be changed to successfully install your RTU Open. The
MAC address of the controller must be unique on its network.
To set the controller's communications protocol and baud rate
RTU Open's
SW3
DIP switches are used to set the controller's protocol and baud rate. The protocol and speed
selection is determined by the network on which the controller will be installed. For Carrier BACnet
implementations, select MS/TP @ 76.8 k as follows:
1 Power down the RTU Open. The controller reads the protocol and baud rate each time you apply power to it.
2 Set
SW3
DIP switches 1, 2, and 4 to
On
to configure the controller for BACnet MS/TP and 76.8 k baud.
3 Power up the RTU Open.
NOTE
Other protocols and baud rates are available. See the RTU Open Integration Guide for additional
instructions.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
12
Wiring for communications
The RTU Open communicates using BACnet on the following types of network segments:
•MS/TP communicating at 9600 bps, 19.2 kbps, 38.4 kbps, or 76.8 kbps
•ARC156 communicating at 156 kbps
NOTE
For more networking details, see the Open Controller Network Wiring Installation Guide.
Wiring specifications for BACnet MS/TP and ARC156
Cable: 22 AWG or 24 AWG, low-capacitance, twisted, stranded, shielded copper wire
Maximum length: 2000 feet (610 meters)
WARNING
Do not apply line voltage (mains voltage) to the controller's ports and terminals.
To wire the controller to the BACnet network
1 Pull the terminal connectors from the RTU Open's power terminals.
2 Check the communications wiring for shorts and grounds.
3 Connect the communications wiring to the Network Comm J19 port's screw terminals labeled
Net +
,
Net -
,
and
Shield
.
NOTE
Use the same polarity throughout the network segment.
4 Set the communication type and baud rate.
For...
Set DIP switches 1 and 2 to...
Set DIP switch 4 to...
MS/TP The appropriate baud rate. See the
MS/TP Baud
diagram
on the controller.
On
ARC156 N/A. Baud rate will be 156 kbps regardless of the DIP
switch settings.
Off
NOTE
Use the same baud rate for all controllers on the network segment.
5 Wire the controllers on a BACnet MS/TP or BACnet ARC156 network segment in a daisy-chain configuration.
6 If the RTU Open is at either end of a network segment, connect a BT485 to the RTU Open.
7 Insert the power screw terminal connector into the RTU Open's power terminals.
8 Verify communication with the network by viewing a Module Status report in the i-Vu® interface.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
13
Wiring inputs and outputs
RTU Open Inputs and Outputs Table
Channel
Number
Type
Signal
Function
Part Number
Wire and
Terminal
Numbers
Alternate
Terminals
Input 1
AI
4-20 mA
CO2
OAQ
Space Relative Humidity
33ZCT55CO2 33ZCT56CO2
33ZCSPTCO2-01
33ZCSPTCO2LCD-01
w/ 33ZCASPCO2
33ZCSENSRH-02
J4
- 5 & 6
N/A
Input 2
AI
4-20 mA
CO2
OAQ
Space Relative Humidity
33ZCT55CO2 33ZCT56CO2
33ZCSPTCO2-01
33ZCSPTCO2LCD-01
w/ 33ZCASPCO2
33ZCSENSRH-02
J4
- 2 & 3
N/A
Input 3
BI
24 Vac
Compressor Safety **2
Fan Status
Filter Status
Remote Occupancy
Door Contact
N/A
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J1
- 2
J5
- 5 & 6 ***
Input 4
BI
24 Vac
Safety Chain *
N/A
J1 - 9
N/A
Input 5
BI
24 Vac
Fire Shutdown **
1,
2
Fan Status
Filter Status
Remote Occupancy
Door Contact
Field-supplied
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J1 - 10
J5 - 3 & 4 ***
Input 6
AI
10K
Thermistor
Supply Air Temperature
33ZCSENSAT 33ZCSENDAT
J2
- 1 & 2
N/A
Input 7
AI
10K
Thermistor
Outside Air Temperature
33ZCSENOAT
J2
- 3 & 4
N/A
Input 8
BI
24 Vac
Enthalpy **
Fan Status
Filter Status
Remote Occupancy
Door Contact
33SENTHSW
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J2 - 6 & 7
J5 - 1 & 2 ***
Input 9
BI
24 Vac
IGC Input****
Humidistat **
Fan Status
Filter Status
Remote Occupancy
Door Contact
--HL--38MG-029
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J5
- 7 & 8
N/A
Input 10
AI
10K
Thermistor
Space Temperature
33ZCT55SPT 33ZCT56SPT
33ZCT59SPT
J20
- 1 & 2
N/A
Input 11
AI
100K
Thermistor
Space Temperature
Setpoint Adjust
33ZCT56SPT 33ZCT59SPT
J20
- 3 & 4
N/A
Rnet
AI
ZS sensors
Wireless Adapter for
wireless sensors
Equipment Touch
TruVu™ ET Display
See Wiring devices to the Rnet
port.
J13 - 1, 2, 3,
4
N/A
AO - 1
AO
4-20 mA
Economizer
Actuator-Field-supplied
J2
- 5 & 4
N/A

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
14
Channel
Number
Type
Signal
Function
Part Number
Wire and
Terminal
Numbers
Alternate
Terminals
AO - 2
AO
0-10 Vdc or
2-10 Vdc
Variable Frequency Drive
Field-supplied
J22
- 1 & 2
N/A
BO - 1
BO
N/A - Relay
Fan (G)
N/A
J1
- 4
N/A
BO - 2
BO
N/A - Relay
Heat 2 (W2) Output
N/A
J1
- 5
N/A
BO - 3
BO
N/A - Relay
Heat 1 (W1) Output
N/A
J1
- 6
N/A
BO - 4
BO
N/A - Relay
Cool 2 (Y2) Output
N/A
J1
- 7
N/A
BO - 5
BO
N/A - Relay
Cool 1 (Y1) Output
N/A
J1
- 8
N/A
BO - 6
BO
N/A - Relay
Humidi-MiZer™
N/A
J11
- 7 & 8
N/A
BO - 7
BO
N/A - Relay
Reversing Valve / High
Speed Fan / Y3
N/A
J11
- 5 & 6
N/A
BO - 8
BO
N/A - Relay
Power Exhaust
N/A
J11 - 2 & 3
N/A
Legend
AI
-Analog Input
AO
- Analog Output
BI
-Digital Input
BO
- Digital Output
*
Safety Chain Feedback
- 24 Vac required at this wire to provide
Run Enabled
status. Provide a jumper from
J1
- 1 to
J1
- 9
if no safeties are used. See To wire inputs and outputs (page 16) for additional information on the RTU Open wiring harness
assembly terminations.
**
Default input function
***
Parallel screw terminal at J5 (J5 - 1 = J2 - 6, J5 - 3 = J1 - 10, J5 - 5 = J1 - 2) may be used in place of the associated flying
leads at the harness (Part# OPN-RTUHRN). See To wire inputs and outputs (page 16) for additional information.
****
Binary Input 9: Integrated Gas Control reports status and if the flame is present.
1
N.C. contact must be used as a primary safety device for approved fire shutdown operation. N.O. contact for monitoring only.
2
If a function other the default is used, do NOT connect wires from J1-x.
Input wiring specifications
Input
Maximum length
Minimum gauge
Shielding
Thermistor 1000 feet
(305 meters)
22 AWG Unshielded
4-20 mA 3000 feet
(914 meters)
22 AWG Unshielded
Binary input
1000 feet
(305 meters)
22 AWG Unshielded
ZS sensors
Wireless Adapter for
wireless sensors
Equipment Touch
TruVu™ ET Display
See Wiring devices to the RTU Open's Rnet port (page 22).

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
15
Inputs
These RTU Open inputs accept the following signal types:
These
inputs...
Support this
signal type...
Description
1, 2 4-20 mA The input resistance on the positive (+) terminal is 250 Ohms.
The Aux Power Out terminal is capable of supplying 24 Vdc to a
4-20 mA transducer, but the total current demanded must not
exceed 40 mA. If the voltage measured from the Aux Power Out
terminal to Gnd is less than 18 Vdc, you need to use an external
power supply.
3, 5, 8, 9 Binary (24 Vac) 24 Vac voltage, resulting in a 25 mA maximum sense current
when the contacts are closed
6, 7, 10 Thermistor 10 kOhm at 77°F (25°C)
11 100k Potentiometer Typically used for 33CZT56SPT Setpoint Offset Potentiometer
Binary outputs
The RTU Open has 8 binary outputs. You can connect each output to a maximum of 24 Vac/Vdc. Each output is a
dry contact rated at 3 A, 24 V maximum, and is normally open.
To size output wiring, consider the following:
•Total loop distance from the power supply to the controller, and then to the controlled device
NOTE
Include the total distance of actual wire. For 2-conductor wires, this is twice the cable length.
•Acceptable voltage drop in the wire from the controller to the controlled device
•Resistance (Ohms) of the chosen wire gauge
•Maximum current (Amps) the controlled device requires to operate
Analog outputs
The RTU Open has 2 analog outputs that support voltage or current devices.
AO-1 -
2-10 Vdc or 4-20 mA (Configure on jumper J3)
AO-2 -
0-10 Vdc or 2-10 Vdc
NOTE
The controlled output device must share the same ground as the controller. When used as a 4-20 mA
output, the load must have an input impedance of 500 Ohms or less. If the output is used as a voltage type
output, then the load impedance must be 10K ohms or greater.

Installing the RTU Open
RTU Open v3 CARRIER CORPORATION ©2019
Installation and Start-up Guide All rights reserved
16
To wire inputs and outputs
1 Turn
off
the RTU Open's power.
2 Connect the input wiring to the screw terminals on the RTU Open.
3 Turn
on
the RTU Open's power.
4 Set the appropriate jumpers on the RTU Open.
J3
AO - 1 0 - 10 Vdc/4-20 mA
W1
Battery Jumper In (Do not remove)
W2
Format Jumper* Out
W3
Input 11 mA Jumper Out (mA not used on this channel)
W4
Input 11 Thermistor In (default position)
W5
Input 10 mA Jumper Out (mA not used on this channel)
W6
Input 10 Thermistor Jumper •In (default position)
Turn off the RTU Open's power.
•Connect the input wiring to the screw terminals on the RTU
Open.
•Turn on the RTU Open's power.
•Set the appropriate jumpers on the RTU Open.