Carrier RTU OPEN 11 808 427 01 User Manual

RTU Open  
Installation and Start-up Guide  
CARRIER CORPORATION ©2010  
A member of the United Technologies Corporation family · Stock symbol UTX · Catalog No. 11-808-427-01 · 11/19/2010  
Table of Contents  
Introduction.................................................................................................................................................................. 1  
What is the RTU Open controller?......................................................................................................................1  
Specifications........................................................................................................................................................3  
Safety considerations...........................................................................................................................................4  
Installation ................................................................................................................................................................... 5  
Field-supplied hardware ......................................................................................................................................5  
To mount the RTU Open.......................................................................................................................................6  
To wire the controller for power..........................................................................................................................7  
Using the rooftop equipment control power transformer ...................................................................7  
Using an auxiliary control power transformer......................................................................................8  
To set the RTU Open's address...........................................................................................................................9  
To set the RTU Open's communications protocol and baud rate............................................................... 10  
Wiring the RTU Open to the MS/TP network................................................................................................. 10  
Wiring specifications...........................................................................................................................11  
To wire the controller to the network .................................................................................................11  
Wiring inputs and outputs................................................................................................................................ 12  
Input wiring specifications..................................................................................................................13  
Inputs...................................................................................................................................................13  
Binary outputs .....................................................................................................................................14  
Analog output ......................................................................................................................................14  
To wire inputs and outputs .................................................................................................................14  
Wiring sensors to inputs................................................................................................................................... 18  
Field-supplied sensor hardware .........................................................................................................19  
Wiring an SPT sensor ..........................................................................................................................20  
Rnet wiring specifications........................................................................................................20  
To wire the SPT sensor to the controller .................................................................................21  
Wiring a Supply Air Temperature sensor............................................................................................21  
Wiring specifications ................................................................................................................22  
To wire the SAT sensor to the controller .................................................................................22  
Wiring a Duct Air Temperature sensor...............................................................................................22  
Wiring specifications ................................................................................................................22  
To wire a duct sensor to the controller ...................................................................................23  
Wiring an Outdoor Air Temperature sensor .......................................................................................23  
Wiring specifications ................................................................................................................23  
To wire an OAT sensor to the controller ..................................................................................23  
Wiring a CO2 sensor............................................................................................................................24  
Wiring specifications ................................................................................................................24  
To wire the CO2 sensor to the controller ................................................................................24  
Wiring an Outdoor Air Quality sensor .................................................................................................25  
Wiring specifications ................................................................................................................26  
To wire the OAQ sensor to the controller ................................................................................26  
Wiring a Relative Humidity sensor .....................................................................................................26  
Wiring specifications ................................................................................................................27  
To wire the RH sensor to the controller...................................................................................27  
Wiring a Humidistat.............................................................................................................................27  
Wiring specifications ................................................................................................................27  
To wire a humidistat to the controller .....................................................................................28  
Wiring an enthalpy switch...................................................................................................................28  
Wiring specifications ................................................................................................................28  
To wire an enthalpy switch (outdoor air) to the controller .....................................................29  
To wire an enthalpy switch (differential) to the controller......................................................30  
RTU Open  
i
Table of Contents  
Wiring a status switch.........................................................................................................................31  
Wiring specifications ................................................................................................................31  
To wire a status switch to the controller .................................................................................32  
Wiring a compressor safety ................................................................................................................32  
Wiring specifications ................................................................................................................32  
To wire a compressor safety input to the controller...............................................................33  
Wiring an occupancy switch or door contact .....................................................................................33  
Wiring specifications ................................................................................................................33  
To wire an occupancy switch or door contact.........................................................................34  
Start-up.......................................................................................................................................................................35  
Service Test......................................................................................................................................................... 36  
Configuring the RTU Open's properties .......................................................................................................... 37  
Unit Configuration properties .............................................................................................................37  
Setpoint properties..............................................................................................................................39  
Service Configuration properties........................................................................................................40  
Sequence of Operation .............................................................................................................................................42  
Occupancy........................................................................................................................................................... 42  
Supply fan ........................................................................................................................................................... 43  
Cooling................................................................................................................................................................. 43  
Economizer ......................................................................................................................................................... 44  
Power Exhaust.................................................................................................................................................... 44  
Unoccupied Free Cooling.................................................................................................................................. 45  
Optimal Start...................................................................................................................................................... 45  
Enthalpy control................................................................................................................................................. 46  
Indoor Air CO2.................................................................................................................................................... 46  
Heating................................................................................................................................................................ 47  
Heat Pump operation........................................................................................................................................ 48  
Dehumidification ............................................................................................................................................... 48  
Demand Limit..................................................................................................................................................... 49  
Door switch......................................................................................................................................................... 49  
Remote occupancy............................................................................................................................................ 49  
Fire Shutdown .................................................................................................................................................... 49  
Compressor Safety ............................................................................................................................................ 49  
Fan Status........................................................................................................................................................... 50  
Filter Status ........................................................................................................................................................ 50  
Alarms ................................................................................................................................................................. 50  
Linkage................................................................................................................................................................ 53  
Linkage Air Source Modes................................................................................................................................ 54  
Troubleshooting.........................................................................................................................................................55  
Serial number..................................................................................................................................................... 55  
LED's .................................................................................................................................................................... 55  
Replacing the RTU Open's battery .................................................................................................................. 56  
Compliance ................................................................................................................................................................57  
FCC Compliance................................................................................................................................................. 57  
CE Compliance ................................................................................................................................................... 57  
BACnet Compliance........................................................................................................................................... 57  
Appendix A: RTU Open Points/Properties ..............................................................................................................58  
Status................................................................................................................................................................... 58  
Unit Configuration.............................................................................................................................................. 59  
Setpoints............................................................................................................................................................. 61  
Alarm Configuration .......................................................................................................................................... 65  
Service Configuration........................................................................................................................................ 66  
Maintenance....................................................................................................................................................... 68  
Alarms ................................................................................................................................................................. 70  
ii  
RTU Open  
Table of Contents  
Linkage................................................................................................................................................................ 71  
I/O Points............................................................................................................................................................ 71  
Appendix B: Single Point Linkage and Device Address Binding............................................................................73  
Single Point Linkage ......................................................................................................................................... 73  
Device Address Binding .................................................................................................................................... 74  
Index ...........................................................................................................................................................................75  
RTU Open  
iii  
Introduction  
What is the RTU Open controller?  
The RTU Open controller is available as an integrated component of a Carrier rooftop unit, or as a field-  
installed retrofit product. 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).  
On board DIP switches allow you to select the baud rate and choose one of the following protocols:  
BACnet  
Modbus  
Johnson N2  
LonWorks  
Carrier’s diagnostic display tools such as BACview6 Handheld or Virtual BACview can be used with the RTU  
Open controller via the J12 Access Port. See illustration on the following page.  
RTU Open  
1
Introduction  
2
RTU Open  
Specifications  
RTU Open driver  
drv_rtuopn_std  
Power  
24 Vac ±10%, 50–60 Hz  
20 VA power consumption (26 VA with BACview attached)  
26 Vdc (25 V min, 30 V max)  
Single Class 2 source only, 100 VA or less  
To connect a BACview6 Handheld, Virtual BACview, or Field Assistant  
Access port J12  
Rnet port J13  
For SPT sensors and a BACview6 in any of the following combinations, wired  
in a daisy-chain configuration:  
1 SPT Plus or SPT Pro  
1–4 SPT Standards  
1–4 SPT Standards, and 1 SPT Plus or SPT Pro  
Any of the above combinations, plus a BACview6, but no more than 6 devices  
total  
Comm Option port  
Inputs  
For communication with the LonWorks Option Card.  
12 inputs:  
Inputs 1 - 2:  
4-20 mA only  
Binary, 24 Vac  
Thermistor  
Inputs 3, 5, 8, 9:  
Inputs 6 - 7:  
Inputs 10 - 11:  
Rnet sensor  
Thermistor  
Binary outputs  
Analog output  
8 relay outputs, contacts rated at 3 A max @ 24 Vac  
Configured normally open.  
1 analog output  
AO1: 2 - 10 Vdc or 4-20 mA  
10 bit D/A  
Output resolution  
Real-time clock  
Battery  
Battery-backed real-time clock keeps track of time in event of power failure  
10-year Lithium CR2032 battery provides a minimum of 10,000 hours of  
data retention during power outages  
Protection  
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, and output  
connections are also protected against voltage transient and surge events.  
Status indicators  
LED's 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  
RTU Open  
3
Introduction  
Overall dimensions  
A:  
B:  
6-1/2 in. (16.5 cm)  
6-1/2 in. (16.5 cm)  
Mounting dimensions  
Panel depth  
7 mounting holes in various positions  
2-1/2 in. (6.4 cm)  
Weight  
11.2 oz (0.32 kg)  
BACnet support  
Conforms to the Advanced Application Controller (B-AAC) Standard Device  
Profile as defined in ANSI/ASHRAE Standard 135-2004 (BACnet) Annex L  
Listed by  
UL-873, FCC Part 15-Subpart B-Class A, CE EN50082-1997  
Safety considerations  
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.  
4
RTU Open  
Installation  
To install the RTU Open:  
1
2
Mount the controller (page 6).  
Wire the controller for power (page 7).  
Using the rooftop equipment control power transformer (page 7).  
Using an auxiliary control power transformer (page 8).  
3
4
5
Set the controller's address (page 9).  
Wire inputs and outputs (page 12).  
Wire sensors to the controller (page 18).  
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  
RTU Open  
5
Installation  
To mount the RTU Open  
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.  
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.  
We highly recommend that you mount the RTU Open in the unit control panel!  
6
RTU Open  
 
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.  
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 8).  
Using the rooftop equipment control power transformer  
1
2
Remove power from the 24 Vac transformer.  
Remove connector assembly from RTU Open's J1 connector.  
RTU Open  
7
   
Installation  
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
5
Apply power to the rooftop equipment.  
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
7
Attach harness to RTU Open connector J1.  
NOTE The harness and connector are keyed and must be oriented properly for correct installation.  
Verify that the Power LED is on and the Run LED is blinking.  
Using 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
2
Verify the available primary voltage at the rooftop equipment.  
Remove power from the rooftop equipment and install the appropriate auxiliary transformer. Follow the  
manufacturer’s installation instructions.  
3
4
Ground one leg of the auxiliary transformer’s secondary wiring.  
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
7
8
9
Repeat step 4 to rewire.  
Remove connector assembly from RTU Open's J1 connector.  
Connect the auxiliary transformer wires to J1 wires 1 (24 Vac) and 3 (Gnd).  
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.  
8
RTU Open  
 
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  
***  
To set the RTU Open'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.  
CAUTION The MAC address of the controller must be unique on its network.  
RTU Open  
9
 
Installation  
1
2
Turn off the RTU Open's power. The controller reads the address each time you apply power to it.  
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.  
3
Turn on the RTU Open's power.  
NOTE The factory default setting is "00" and must be changed to successfully install your RTU Open.  
To set the RTU Open'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.  
Wiring the RTU Open to the MS/TP network  
The RTU Open communicates using BACnet on an MS/TP network segment communications at 9600 bps,  
19.2 kbps, 38.4 kbps, or 76.8 kbps.  
Wire the controllers on an MS/TP network segment in a daisy-chain configuration.  
10  
RTU Open  
Install a BT485 on the first and last controller on a network segment to add bias and prevent signal  
distortions due to echoing.  
See the MS/TP Networking and Wiring Installation Guide for more details.  
Wiring specifications  
Cable:  
Maximum length:  
22 AWG or 24 AWG, low-capacitance, twisted, stranded, shielded copper wire  
2000 feet (610 meters)  
To wire the controller to the network  
1
2
3
Pull the screw terminal connector from the controller's power terminals labeled Gnd and 24 Vac or Hot.  
Check the communications wiring for shorts and grounds.  
Connect the communications wiring to the BACnet port’s screw terminals labeled Net +, Net -, and  
Shield.  
NOTE Use the same polarity throughout the network segment.  
Verify that the MSTP jumper is set to MSTP.  
4
5
Set DIP switches 1 and 2 to the appropriate baud rate. See the MSTP baud diagram on the RTU Open.  
The default baud rate is 76.8 kbps.  
NOTE Use the same baud rate for all controllers on the network segment.  
Insert the power screw terminal connector into the RTU Open's power terminals.  
Verify communication with the network by viewing a module status report.  
6
7
RTU Open  
11  
Installation  
Wiring inputs and outputs  
RTU Open Inputs and Outputs Table  
Channel Type  
Number  
Signal  
Function  
Part Number  
Wire/Terminal  
Numbers  
Alternate  
Terminals  
Input 1  
Input 2  
Input 3  
AI  
AI  
BI  
4-20 mA  
CO2  
OAQ  
33ZCT55CO2  
33ZCT56CO2  
33ZCSENCO2 w/  
33ZCASPCO2  
N/A  
J4 - 5 & 6  
J4 - 2 & 3  
J1 - 2  
Space Relative Humidity  
33ZCSENSRH-01  
4-20 mA  
24 Vac  
CO2  
33ZCT55CO2  
33ZCT56CO2  
33ZCSENCO2 w/  
33ZCASPCO2  
N/A  
OAQ  
Space Relative Humidity  
33ZCSENSRH-01  
N/A  
Compressor Safety **  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
J5 - 5 & 6  
***  
33CSAS-01  
33CSFS=01  
Field-supplied  
Field-supplied  
Input 4  
Input 5  
BI  
BI  
24 Vac  
24 Vac  
Safety Chain *  
N/A  
N/A  
J1 - 9  
Fire Shutdown **  
Fan Status  
Field-supplied  
33CSAS-01  
J1 - 10  
J5 - 3 & 4  
***  
Filter Status  
33CSFS-01  
Remote Occupancy  
Door Contact  
Field-supplied  
Field-supplied  
Input 6  
Input 7  
Input 8  
AI  
AI  
BI  
10K  
Thermistor  
Supply Air Temperature  
33ZCSENSAT  
33ZCSENDAT  
N/A  
N/A  
J2 - 1 & 2  
J2 - 3 & 2  
J2 - 6 & 7  
10K  
Thermistor  
Outside Air Temperature  
33ZCSENOAT  
24 Vac  
Enthalpy **  
Fan Status  
33SENTHSW  
33CSAS-01  
J5 - 1 & 2  
***  
Filter Status  
33CSFS-01  
Remote Occupancy  
Door Contact  
Humidistat **  
Fan Status  
Field-supplied  
Field-supplied  
TSTATCCPLH01-B  
33CSAS-01  
Input 9  
BI  
24 Vac  
N/A  
J5 - 7 & 8  
Filter Status  
33CSFS-01  
Remote Occupancy  
Door Contact  
Space Temperature  
Field-supplied  
Field-supplied  
33ZCT55SPT 33ZCT56SPT  
33ZCT59SPT  
Input 10  
Input 11  
AI  
AI  
10K  
Thermistor  
N/A  
N/A  
J20 - 1 & 2  
J20 - 3 & 4  
100K  
Thermistor  
Space Temperature  
Setpoint Adjust  
33ZCT56SPT 33ZCT59SPT  
Rnet  
AI  
Zone Temperature  
SPS / SPPL / SPP  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
J13 - 1, 2, 3, 4  
J2 - 5 & 4  
J22 - 1 & 2  
J1 - 4  
AO - 1  
AO - 2  
BO - 1  
BO - 2  
BO - 3  
BO - 4  
BO - 5  
AO  
AO  
BO  
BO  
BO  
BO  
BO  
Economizer  
N/A  
Economizer  
Actuator-Field-supplied  
Not used  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A - Relay  
N/A - Relay  
N/A - Relay  
N/A - Relay  
N/A - Relay  
Fan (G)  
Heat 2 (W2) Output  
Heat 1 (W1) Output  
Cool 2 (Y2) Output  
Cool 1 (Y1) Output  
J1 - 5  
J1 - 6  
J1 - 7  
J1 - 8  
BO - 6  
BO - 7  
BO  
BO  
N/A - Relay  
N/A - Relay  
Humidi-MiZer™  
Reversing Valve  
N/A  
N/A  
N/A  
N/A  
J11 - 7 & 8  
J11 - 4 & 6  
12  
RTU Open  
 
Channel Type  
Number  
Signal  
Function  
Part Number  
Wire/Terminal  
Numbers  
Alternate  
Terminals  
BO - 8  
BO  
N/A - Relay  
Power Exhaust  
N/A  
N/A  
J11 - 1 & 3  
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 utilized. See To wire inputs and outputs (page 14) 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 (OPN-RTUHRN). See To wire inputs and outputs (page 14) for additional information.  
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  
22 AWG  
Unshielded  
Unshielded  
1000 feet  
Binary input  
(305 meters)  
SPT (RNET)  
500 feet  
(152 meters)  
22 AWG  
4 conductor  
Unshielded  
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  
11  
Thermistor  
10 kOhm at 77° F  
100k Potentiometer  
Typically used for 33CZT56SPT Setpoint Offset Potentiometer  
RTU Open  
13  
Installation  
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 output  
The RTU Open has 1 analog output that supports voltage or current devices. The controlled device must share  
the same ground as the controller and have input impedance of 500 Ohms maximum for the 4-20 mA mode  
on AO - 1.  
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
4
Turn on the RTU Open's power.  
Set the appropriate jumpers on the RTU Open.  
AO - 1  
0 - 10 Vdc/4-20 mA  
J3  
Battery Jumper  
In (Do not remove)  
W1  
W2  
W3  
W4  
W5  
W6  
Format Jumper*  
Input 11 mA Jumper  
Input 11 Thermistor  
Input 10 mA Jumper  
Input 10 Thermistor Jumper  
Out  
Out (mA not utilized on this channel)  
In (default position)  
Out (mA not utilized on this channel)  
In (default position)  
*Formatting the controller may result in lost information and should only be done under the guidance of  
Carrier Control Systems Support.  
14  
RTU Open  
 
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  
***  
J4 Inputs  
1
2
Turn off the RTU Open's power.  
Connect the input and output wiring to the screw terminals on the RTU Open.  
NOTE When utilizing the controller's 24 Vdc auxiliary power out, the total current demand for these two  
input channels must not exceed 40 mA (100mA per channel).  
RTU Open  
15  
Installation  
NOTE J4 Analog Inputs 1 and 2 may be set for the following device types:  
IAQ Sensor  
OAQ Sensor  
Space RH Sensor  
J5 Inputs  
The terminals for Inputs 3, 5, and 8 are available for use in place of the flying wire leads at Molex  
connectors J1 and J2 identified below:  
NOTE J5 binary inputs 3, 5, and 8 are the same input channels as:  
J1 wire 2, J5 - Input - 3 (Compressor Safety)  
J1 wire 10, J5 - Input - 5 (Fire Shutdown)  
J2 wire 6, J5 - Input - 8 (Enthalpy Switch).  
16  
RTU Open  
These terminals are available for use in place of the flying wire leads at Molex connectors J1 and J2.  
Binary inputs are configurable and may be used for the following functions:  
Input  
3
Default input function  
Compressor Safety  
Additional functions  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
Fire Shutdown  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
5
8
Enthalpy Switch  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
HumidiStat  
Fan Status  
Filter Status  
9
Remote Occupancy  
Door Contact  
J11 Outputs  
RTU Open  
17  
Installation  
NOTE Output relay contacts rated at 3A, 24V maximum. Install pilot relays required by application.  
NOTE J20 Analog Inputs 10 and 11 are reserved for a 10k Ohm space temperature sensor with an  
optional 100k Ohm offset potentiometer used for setpoint adjustment.  
Wiring sensors to inputs  
You may wire various sensors to the RTU Open's inputs. See the table below for details.  
NOTE This document gives instructions for wiring the sensors to the RTU Open. For specific mounting and  
wiring instructions, see the Carrier Sensors Installation Guide.  
All field control wiring that connects to the RTU Open must be routed through the raceway built into the corner  
post. The raceway provides the UL-required clearance between high-and low-voltage wiring.  
1
2
3
4
Pass the control wires through the hole provided in the corner post.  
Feed the wires through the raceway to the RTU Open.  
Connect the wires to the removable Phoenix connectors.  
Reconnect the connectors to the board (where removed).  
18  
RTU Open  
 
NOTE For rooftop unit installation, see the base unit installation instructions.  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could cause personal injury, death, and/or equipment damage.  
Disconnect all power to the unit before performing maintenance or service. Unit may automatically start if  
power is not disconnected.  
Field-supplied sensor hardware  
The RTU Open controller is configurable with the following field-supplied sensors:  
Sensor  
Part numbers  
Notes  
Space temperature sensor  
(page 20)  
SPS, SPPL, SPP, 33ZCT55SPT,  
33ZCT56SPT, 33ZCT59SPT  
Supply air temperature sensor  
33ZCSENSAT  
Factory-installed  
(page 21)  
Duct air temperature sensor  
33ZCSENDAT  
(page 22)  
Outdoor air temperature sensor 33ZCSENOAT  
Factory-supplied with Economizer  
(page 23)  
CO2 sensor (page 24)  
33ZCSENCO2, 33ZCT55CO2,  
33ZCT56CO2  
Required only for demand control  
ventilation - a dedicated 24-vac  
transformer is required  
Outdoor air quality sensor (page 33ZCTSENCO2  
Optional with demand control  
ventilation  
Duct relative humidity sensor  
33ZCSENDRH-01  
33ZCSENSRH-01  
Space relative humidity sensor  
(page 26)  
Humidistat (page 27)  
TSTATCCPLH01-B  
C33ZCCASPCO2  
CO2 aspirator box (page 24)  
Required for CO2 return duct/outside  
air applications  
Outdoor air enthalpy switch  
(page 28)  
33CSENTHSW  
33CSENTSEN  
Return air enthalpy sensor  
Optional with  
33CSSENTHSW  
(page 28)  
Filter status switch (page 31)  
Fan status switch (page 31)  
33CSFS-01  
33CSAS-01 or field-supplied  
For specific details about sensors, see the Carrier Sensors Installation Guide.  
RTU Open  
19  
Installation  
Wiring an SPT sensor  
The RTU Open is connected to a wall-mounted space temperature sensor to monitor room temperature.  
An i-Vu Open Control System offers the following SPT sensors:  
Sensor  
Part #  
Features  
Local access port  
No operator control  
SPT Standard  
SPS  
Slide potentiometer to adjust setpoint  
MANUAL ON button to override schedule  
LED to show occupied status  
Local access port  
SPT Plus  
SPPL  
LCD display  
SPT Pro  
SPP  
MANUAL ON button to override schedule  
WARMER and COOLER buttons to adjust setpoint  
INFO button to cycle through zone and outside air temperatures,  
setpoints, and local override time  
Local access port  
You wire SPT sensors to the RTU Open's Rnet port. An Rnet can consist of any of the following combinations  
of devices wired in a daisy-chain configuration:  
1 SPT Plus or SPT Pro  
1–4 SPT Standards  
1–4 SPT Standards, and 1 SPT Plus or SPT Pro  
Any of the above combinations, plus up to 2 BACview6's but no more than 6 devices total  
NOTES  
If you have 2 BACview6's, the second BACview6 must have a separate power supply with the same  
ground as the controller.  
If the Rnet has multiple SPT Standard sensors, you must give each a unique address on the Rnet. See  
the Carrier Sensors Installation Guide.  
If the Rnet has multiple BACviews, you must give each a unique address on the Rnet. See the BACview  
Installation and User Guide.  
Rnet wiring specifications  
NOTE Use the specified type of wire and cable for maximum signal integrity.  
Description  
Conductor  
4 conductor, unshielded, CMP, plenum rated cable  
18 AWG  
Maximum length  
500 feet (152 meters)  
Recommended coloring  
Jacket: White  
Wiring: Black, white, green, red  
UL temperature rating  
32–167°F (0–75°C)  
20  
RTU Open  
 
Voltage  
Listing  
300 Vac, power limited  
UL: NEC CL2P, or better  
To wire the SPT sensor to the controller  
1
Partially cut, then bend and pull off the outer jacket of the Rnet cable(s). Do not nick the inner insulation.  
Strip about .25 inch (.6 cm) of the inner insulation from each wire.  
Outer Jacket  
.25 in.  
Inner insulation  
(.6 cm)  
2
Wire each terminal on the sensor to the same terminal on the controller. See diagram below.  
NOTE Carrier recommends that you use the following Rnet wiring scheme:  
Connect this wire...  
To this terminal...  
Red  
+12V  
Rnet-  
Rnet+  
Gnd  
Black  
White  
Green  
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 when the rooftop unit is equipped with electric heating.  
RTU Open  
21  
 
Installation  
Wiring specifications  
Cable from sensor to controller:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
Maximum length:  
500 feet (152 meters)  
To wire the SAT sensor to the controller  
1
2
3
4
Connect the wiring harness (OPN-RTUHRN). For details, see To wire inputs and outputs (page 14).  
Wire the sensor to the wiring harness. See diagram below.  
Connect to J2 wires 1 and 2.  
Verify your sensor readings.  
Wiring a Duct Air Temperature sensor  
Part #33ZCSENDAT  
The RTU Open requires a temperature sensor installed in the supply air stream. The Duct Temperature (DAT)  
sensor is generally used when the rooftop unit is NOT equipped with electric heating.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
22  
RTU Open  
 
To wire a duct sensor to the controller  
1
2
3
4
5
Connect the wiring harness (Part#OPN-RTUHRN). For details, see To wire inputs and outputs (page 14).  
Wire the sensor to the wiring harness. See diagram below.  
Connect to J2 wires 1 and 2.  
Verify your sensor readings.  
Drill .25" diameter hole. Pass sensor leads through bushing and insert assembly into hole. Secure leads  
to ductwork with aluminum tape.  
NOTE Sensor termination requires installation of RTU Open wiring harness assembly (Part #OPN-RTUHRN).  
Wiring an Outdoor Air Temperature sensor  
Part #33ZCSENOAT  
Outdoor Air Temperature (OAT) is required to utilize all of the RTU Open’s features. OAT may be provided by a  
local sensor (shown below) or a linked sensor in another controller. See Single Point Linkage (page 73).  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
To wire an OAT sensor to the controller  
1
2
Connect the wiring harness (Part#OPN-RTUHRN). For details, see To wire inputs and outputs (page 14).  
Wire the sensor to the wiring harness. See diagram below.  
RTU Open  
23  
 
Installation  
3
4
Connect to J2 wires 3 and 4.  
Verify your sensor readings.  
Wiring a CO2 sensor  
Part #33ZCSENCO2 (Display model)  
Part #33ZCT55CO2 (No display)  
Part #33ZCT56CO2 (No display)  
A CO2 sensor monitors carbon dioxide levels. As CO2 levels increase, the RTU Open adjusts the outside air  
dampers to increase ventilation and improve indoor air quality. A CO2 sensor can be wall-mounted or  
mounted in a return air duct. 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 CO2 sensor’s power requirements  
exceed what is available at J4 - 1 and 4. Provide a dedicated 24Vac transformer or DC power supply  
Wiring specifications  
Cable from sensor to controller:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
Maximum length:  
500 feet (152 meters)  
To wire the CO2 sensor to the controller  
1
2
3
Wire the sensor to the controller. See appropriate diagram below.  
Install a field-supplied dedicated 24 Vac transformer or DC power supply.  
Wire the sensor to the controller.  
24  
RTU Open  
 
Wiring diagram for #33ZCSENCO2:  
Wiring diagram for #33ZCT55/56CO2:  
Wiring an Outdoor Air Quality sensor  
Part #33ZCSENCO2 (Display model)  
An outdoor air quality (OAQ) sensor monitors outside air carbon dioxide levels. The RTU Open uses this  
information, in conjunction with a CO2 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).  
RTU Open  
25  
 
Installation  
The sensor has a range of 0–2000 ppm and a linear 4-20 mA output. The CO2 sensor’s power requirements  
exceed what is available at J4 - 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)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
Maximum length:  
500 feet (152 meters)  
To wire the OAQ sensor to the controller  
1
2
3
Wire the sensor to the controller. See appropriate diagram below.  
Install a field-supplied dedicated 24 Vac transformer or DC power supply.  
Apply power and verify sensor readings.  
Wiring diagram for #33ZCSENCO2:  
NOTE Sensor may be terminated at Input 1 or 2.  
Wiring a Relative Humidity sensor  
Wall sensor - Part #33ZCSENSRH-01  
Duct sensor - Part #OPNSENRH-01  
The Relative Humidity (RH) sensor may be used for zone humidity control (dehumidification) when applied to  
a Carrier rooftop unit equipped with the Humidi-MiZer™ option. On units not equipped for dehumidification,  
the sensor monitors humidity, but provides no control.  
NOTE You cannot use a relative humidity sensor when using both a CO2 and OAQ sensor on the controller.  
26  
RTU Open  
 
Wiring specifications  
Cable from sensor to controller:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
Maximum length:  
500 feet (152 meters)  
To wire the RH sensor to the controller  
1
Strip the outer jacket from the cable for at least 4 inches (10.2 cm). Strip .25 inch (.6 cm) of insulation  
from each wire.  
2
3
Wire the sensor to the controller. See diagram below.  
Apply power and verify sensor readings.  
NOTE Sensor may be terminated at Input 1 or 2.  
Wiring a Humidistat  
Locally Purchased  
A humdistat may be used for zone humidity control (dehumidification) when applied to a Carrier rooftop unit  
equipped with the Humidi-MiZer™ option. On units not equipped for dehumidification, the humidistat will  
indicate a high humidity condition only.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
RTU Open  
27  
 
Installation  
To wire a humidistat to the controller  
1
Strip the outer jacket from the cable for at least 4 inches (10.2 cm). Strip .25 inch (.6 cm) of insulation  
from each wire  
2
3
Wire the humidistat to the controller. See diagram below.  
Apply power and verify sensor readings.  
NOTE Humidistat may be return duct or space mounted.  
Wiring an enthalpy switch  
Outdoor Air - Part #33CSENTHSW  
Return air - Part #33CSENTSEN  
The 33CSENTHSW is an outdoor air enthalpy switch/receiver. This control determines the suitability of the  
outdoor air as a cooling source, based on the heat content of the air. Differential enthalpy control requires  
installing a 33CSENTSEN enthalpy sensor in the rooftop unit's return air duct.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
28  
RTU Open  
 
To wire an enthalpy switch (outdoor air) to the controller  
An enhalpy switch is typically mounted in the outdoor air inlet.  
Wiring diagram for a field-installed enthalpy switch:  
NOTES  
Factory-installed enthalpy switches terminate at J2 wires 6 (switch input) and 7 (24 Vac).  
Input channel must be configured for the enthalpy contact (N.O. or N.C.) that you use.  
RTU Open  
29  
Installation  
Wiring diagram for factory-installed enthalpy switch:  
NOTE Factory-installed enthalpy switches terminate at J2 wires 6 (switch input) and 7 (24 Vac).  
To wire an enthalpy switch (differential) to the controller  
30  
RTU Open  
Wiring diagram for optional enthalpy sensor mounted in the return air for differential enthalpy:  
Wiring a status switch  
Filter - Part #33CSFS-01 or field-supplied  
Fan status - Part #33CSAS-01 or field-supplied  
Filter and/or fan status switches may be installed to provide a Dirty Filter indication or Fan Running status.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
RTU Open  
31  
 
Installation  
To wire a status switch to the controller  
NOTES  
Binary inputs 3, 5, 8, and 9 are configurable and may be used for Fan Status, Filter Status, Remote  
Occupancy, or Door Contacts, if they have not already been used for their default functions.  
Follow device manufacturer's installation and operating instructions.  
Wiring a compressor safety  
This is typically provided by the manufacturer with the rooftop equipment. A compressor safety status may be  
monitored if available.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
32  
RTU Open  
To wire a compressor safety input to the controller  
NOTES  
An isolation relay may be required if the RTU Open is powered separately from the equipment's control  
power circuit.  
Follow device manufacturer's installation and operating instructions.  
Wiring an occupancy switch or door contact  
Occupancy switch - field-supplied  
Door contact - field-supplied  
Occupancy or door contact switches may be installed to provide an alternate means of occupancy  
determination or heating and cooling lockout. See Sequence of Operation (page 42) for additional details.  
Wiring specifications  
Cable from sensor to controller:  
Maximum length:  
If <100 ft (30.5 meters)  
If >100 ft (30.5 meters)  
22 AWG, unshielded  
22 AWG, shielded  
500 feet (152 meters)  
RTU Open  
33  
Installation  
To wire an occupancy switch or door contact  
NOTES  
Binary Inputs 3, 5, 8, and 9 are configurable and may be used for Fan Status, Filter Status, Remote  
Occupancy, or Door Contacts - provided they have not been utilized for their default functions.  
Follow device manufacturer's installation and operating instructions.  
34  
RTU Open  
Start-up  
To start up the RTU Open, you need one of the following user interfaces to the controller. These items let you  
access the controller information, read sensor values, and test the controller.  
This interface...  
Provides a...  
i-Vu Open software  
Permanent interface  
Temporary interface  
Field Assistant software -  
runs on a laptop connected to controller's Local Access port 1  
Virtual BACview software -  
Temporary interface  
Temporary interface  
Permanent interface  
runs on a laptop connected to controller's Local Access port 1, 2  
BACview6 Handheld keypad/display unit -  
connects to controller's Local Access port 1, 2  
BACview6 keypad/display unit  
connected to controller's Rnet port 2  
1
Requires a USB Link (USB-L).  
See the BACview Installation and User Guide for instructions on connecting and using the above items.  
2
RTU Open  
35  
Start-up  
Service Test  
Navigation:  
i-Vu / Field Assistant:  
BACview:  
Properties > Equipment > Configuration > Service Configuration > Service Test  
HOME > CONFIG > SERVICE > TEST  
Service Test can be used to verify proper operation of compressors, heating stages, indoor fan, power  
exhaust fans, economizer, and dehumidification. It is highly recommended to use Service Test at initial  
system start-up and during troubleshooting. See Appendix A: Points/Properties (page 58) for more  
information.  
Service Test differs from normal operation as follows:  
Outdoor air temperature limits for cooling circuits, economizer, and heating are ignored.  
Normal compressor time guards and other staging delays are ignored.  
Alarm statuses (except Fire and Safety Chain) are ignored, but all alarms and alerts are still broadcast on  
the network, if applicable.  
Service Test can be turned on or off from BACview, Field Assistant, or i-Vu. Select Default Value of Enable to  
turn on and Disable to turn off.  
NOTES  
Service Test mode is password-protected when accessed from a BACview.  
Service Test allows testing of each controller output.  
Binary Service Test functions are on when the Default Value is set to Enable and off when set to Disable.  
The output of the Analog Service Test is controlled by the percentage (0-100%) entered into the Default  
Value.  
It is recommended to return every Service Test variable to Disable or 0.00 after testing each function  
(unless that test variable must be active to test a subsequent function, as in Compressor 2 Test).  
All outputs return to normal operation when Service Test is set to Disable.  
Service Test functions  
Use Fan Test to activate and deactivate the Supply Fan (BO - 1) output. Note that this output may enable  
simultaneously with other Service Test modes even with its Default Value set to Disable.  
Use Compressor 1 Test to activate and deactivate the Compressor 1 (BO - 5) output. The Supply Fan  
output will be activated and deactivated in conjunction with this output. Leave Compressor 1 Test on  
Enable if Compressor 2 Test is required.  
Use Compressor 2 Test to activate and deactivate the Compressor 2 (BO - 4) output. Always test the  
Compressor 1 output first. Compressor 1 Test output must be set to Enable for Compressor 2 Test to  
function.  
Use the Reversing Valve Test to activate and deactivate the reversing valve (BO - 7) output.  
Use the Dehumidification Test to activate and deactivate the Humidi-MiZer™ (BO - 6) output. The Supply  
Fan output will be activated and deactivated in conjunction with the Dehumidification Test output.  
Use Heat 1Test to activate and deactivate the Heat 1 (BO - 3) output. The Supply Fan output is activated  
and deactivated in conjunction with the Heat 1Test output.  
Use Heat 2Test to activate and deactivate the Heat 2 (BO - 2) output. The Supply Fan output is activated  
and deactivated in conjunction with the Heat 2Test output.  
36  
RTU Open  
Use Power Exhaust Test to activate and deactivate the power exhaust (BO - 8) output.  
Use Economizer Test to set the (AO - 1) economizer output to any value from 0 to 100% of configured  
output (2-10 Vdc or 4-20 mA).  
Analog Output 2 Test (AO - 2) is currently unused and does not require testing.  
Service Test mode does not timeout. Return all test variables to Disable or 0.00. Set Service Test to  
Disable or cycle power to the RTU Open to return to normal operation.  
Configuring the RTU Open's properties  
To start up the RTU Open, you need to configure the properties described in the following sections. These  
properties affect the unit operation and/or control. Review and understand the meaning and purpose of each  
property before changing it.  
Unit Configuration properties (page 37)  
Setpoint Configuration properties (page 39)  
Service Configuration properties (page 40)  
See Appendix A (page 58) for a complete list of the controller's points/properties.  
Unit Configuration properties  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Unit Configuration  
HOME > CONFIG > UNIT  
Point Name/Description  
Default/Range  
Fan Mode – The supply fan's operating mode.  
D:  
R:  
Continuous  
Options:  
Auto  
Auto - The fan cycles on/off in conjunction with heating or cooling.  
Continuous - The fan runs continuously during occupancy & intermittently during  
unoccupied periods with heating or cooling.  
Continuous  
Always On  
Always On - The fan runs continuously regardless of occupancy or calls for heating and  
cooling.  
Occupancy Source - The method that the controller uses to determine occupancy.  
D:  
R:  
Always Occupied  
Options:  
Always Occupied  
BACnet Schedule  
BAS On/Off  
Always Occupied = Controller operates continuously as occupied.  
BACnet Schedule = Controller follows a schedule set up in i-Vu or Field Assistant.  
BAS On/Off = Occupancy is set over the network by another device or a third party BAS.  
Remote Occ Input =Occupancy is set by a remote contact.  
Remote Occ Input  
Input 1 Function – The type of sensor (4-20 mA) connected to terminals J4 – 4, 5, & 6.  
D:  
R:  
No Sensor  
No Sensor  
IAQ Sensor  
OAQ Sensor  
Space RH Sensor  
RTU Open  
37  
 
Start-up  
Point Name/Description  
Default/Range  
Input 2 Function – The type of sensor (4-20 mA) connected to terminals J4 – 1, 2, & 3.  
D:  
R:  
No Sensor  
No Sensor  
IAQ Sensor  
OAQ Sensor  
Space RH Sensor  
Input 3 Function – The usage of Input 3. You must also set Input 3 Switch Configuration. D:  
Compressor Safety  
Options:  
R:  
No Function  
Compressor Safety  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
No Function – The input is not used.  
Compressor Safety – Safety device status.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 3 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Input 5 Function – The usage of Input 5. You must also set Input 5 Switch Configuration. D:  
Fire Shutdown  
Options:  
R:  
No Function  
Fire Shutdown  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
No Function – The input is not used.  
Fire Shutdown – Fire Safety device status. Inhibits operation when tripped.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 5 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NC  
NO/NC (normally  
open/normally closed)  
Input 8 Function – The usage of Input 8. You must also set Input 8 Switch Configuration. D:  
Enthalpy Switch  
Options:  
R:  
No Function  
Enthalpy Switch  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
No Function – The input is not used.  
Enthalpy Switch – Indicates enthalpy status (high or low).  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 8 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Input 9 Function – The usage of Input 9. You must also set Input 9 Switch Configuration. D:  
Humidistat  
Options:  
R:  
No Function  
Humidistat  
No Function – The input is not used.  
Humidistat – Indicates high humidity condition.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
38  
RTU Open  
Point Name/Description  
Default/Range  
Input 9 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Space sensor type - The type of local space temperature sensor.  
D:  
R:  
T55  
T55  
T56 (Use for T59)  
SPT Sensor  
None  
Setpoint properties  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Setpoints  
HOME > CONFIG > SETPOINT  
Select a color band on the setpoint graph to see the current setpoints in the Heating and Cooling fields. See setpoint  
descriptions below.  
Point Name/Description  
Default/Range  
Occupied Heating – Green  
The heating setpoint the controller maintains while in occupied mode.  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
70°F  
-40 to 245°F  
74°F  
Occupied Cooling – Green  
The cooling setpoint the controller maintains while in occupied mode.  
-40 to 245°F  
55°F  
Unoccupied Heating – Gray  
The heating setpoint the controller maintains while in unoccupied mode.  
45 to 100°F  
90°F  
Unoccupied Cooling – Gray  
The cooling setpoint the controller maintains while in unoccupied mode.  
-40 to 245°F  
RTU Open  
39  
 
Start-up  
Point Name/Description  
Default/Range  
Optimal Start – The earliest time, prior to occupancy, at which the Optimal Start function  
may begin to adjust the effective setpoints to achieve the occupied setpoints by the time  
scheduled occupancy begins. Enter 0 to disable Optimal Start.  
D:  
R:  
4 hr  
0 to 4 hr  
Occ Relative Humidity Setpoint – The percentage of relative humidity in the space during  
occupancy that will energize BO - 6 (Humidi-MiZer™).  
D:  
R:  
60%rh  
0 to Unoccupied  
RH Control  
Setpoint  
Unocc Relative Humidity Setpoint – The percentage of relative humidity in the space during  
the unoccupied time period that starts the unit and energizes BO - 6 (Humidi-MiZer™).  
D:  
R:  
D:  
R:  
D:  
R:  
95%  
30 to 100%  
650ppm  
DCV Max Ctrl Setpoint – The design difference between indoor and outdoor CO2 levels.  
0 to 9999 ppm  
50% Open  
20 to 90% Open  
Power Exhaust Setpoint - The outside air damper position at which the controller energizes  
the Power Exhaust relay. Configuration >Service Configuration > Economizer Exists must be  
set to Yes, and Configuration >Service Configuration > Continuous Occupied Exhaust must  
be set to No.  
Service Configuration properties  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Service Configuration  
HOME > CONFIG > SERVICE  
Point Name/Description  
Default/Range  
Unit Type – The type of equipment that the RTU Open is controlling.  
D:  
R:  
Heat/Cool  
Options:  
Heat/Cool  
Heat/Cool – Standard rooftop air handling unit.  
HP O/B Ctrl – Heat Pump application, uses reversing valve output to control heating and  
cooling.  
HP O/B Ctrl  
HP Y1/W1 Ctrl  
HP Y1/W1 Ctrl – Carrier Heat Pump application only.  
Compressor Stages – The number of mechanical cooling stages.  
D:  
R:  
One Stage  
One Stage  
Two Stages  
Economizer Exists – Set to Yes to enable economizer control for units equipped with an  
economizer damper.  
D:  
R:  
D:  
R:  
D:  
R:  
No  
No/Yes  
O
Reversing Valve Output – Set to O = Reversing Valve output on with cooling. Set to B =  
Reversing Valve output on with heating.  
O / B  
Heat Type – The type of heating that the unit has.  
Electric  
Electric/Gas  
Number Of Heat Stages – The number of heat stages.  
D:  
2
R: 1 /2 /0 (no heating)  
40  
RTU Open  
 
Point Name/Description  
Default/Range  
Continuous Occupied Exhaust – Configures the exhaust fan control strategy (BO-8). If Yes,  
the power exhaust runs continuously in occupied mode and is off in unoccupied mode. If  
No, the power exhaust is controlled by the Power Exhaust Setpoint.  
D:  
R:  
No  
No/Yes  
Indoor CO2 Sensor Value @min (ma) – The CO2 value that corresponds to a 4mA input at  
the appropriate input channel.  
D:  
R:  
0ppm  
0 to 9999 ppm  
2000 ppm  
Indoor CO2 Sensor Value @max (ma) – The CO2 value that corresponds to a 20mA input at D:  
the appropriate input channel.  
R:  
0 to 9999 ppm  
0ppm  
Outdoor CO2 Sensor Value @min (ma) – The CO2 value that corresponds to a 4 mA input  
at the appropriate input channel.  
D:  
R:  
0 to 9999 ppm  
2000 ppm  
Outdoor CO2 Sensor Value @max (ma) – The CO2 value that corresponds to a 20 mA input D:  
at the appropriate input channel.  
R:  
0 to 9999 ppm  
RTU Open  
41  
Sequence of Operation  
Sequence of Operation  
The RTU Open supports various types of constant volume air source configurations:  
Standard heat/cool unit types with up to 2-stages of mechanical cooling and gas or electric heating  
Heat pump units utilizing a reversing valve output for heating and cooling control  
Heat pump unit (Carrier) with an OEM control board  
Economizer, CO2, Demand Limiting, and RH control strategies are available for appropriately equipped  
units  
The RTU Open may operate as part of a linked VVT system or as a stand-alone controller.  
Occupancy  
The RTU Open’s operation depends upon its occupancy state (Occupied/Unoccupied). The RTU Open  
operates continuously in the Occupied mode until you configure an occupancy schedule.  
An occupancy schedule may be:  
A local schedule configured in the controller using BACview or Field Assistant  
A BACnet schedule configured in i-Vu, networked through an i-Vu Open Router  
A BACnet or local schedule configured for subordinate VVT Zones, networked through an i-Vu Open  
Router(s) and employing Linkage  
To set up occupancy schedules, consult the documentation for your user interface.  
NOTE A BACnet schedule, downloaded from i-Vu will overwrite a local schedule that was set up with BACview  
or Field Assistant.  
Occupancy Source - the following settings determine occupancy. See Unit configuration (page 59).  
Options:  
Always Occupied – Controller operates continuously, regardless of any configured schedule  
BAS On/Off – Occupancy is set over the network by another device or a third party BAS. Refer to the RTU  
Open Integration Guide for additional instructions in communication protocols.  
Remote Occ Input – Controller monitors an input contact connected to one of the available binary inputs  
configured to receive it. You must set Unit Configuration > Occupancy Source to Remote Occ Input and  
one Input Switch Configuration to Remote Occupancy.  
42  
RTU Open  
 
Supply fan  
The RTU Open supply fan may be configured for one of three Fan Modes:  
Auto - The fan cycles on/off in conjunction with heating or cooling  
Continuous - The fan runs continuously during occupancy and intermittently during unoccupied periods  
with heating or cooling  
Always On - The fan runs continuously regardless of occupancy or calls for heating and cooling  
Occupancy can be determined by Linkage, BACnet schedules, BAS schedules, or in response to a remote  
occupancy switch.  
A Unit Start Delay is used when transitioning from Unoccupied to Occupied. A Fan Off Delay allows the supply  
fan to continue operating after heating or cooling stops.  
If the following alarms are active, the fan turns off immediately, regardless of the occupancy state or demand:  
Fire Shutdown  
Safety chain  
SAT alarm  
SPT alarms  
The RTU Open does not include smoke-control functions such as smoke-purge, zone-pressurization, or smoke-  
ventilation. Each of these modes require a field-designed circuit to operate the following, as required by local  
fire codes:  
RTU supply fan  
RTU economizer  
RTU power exhaust  
The RTU Open may be configured to accept a Supply Fan Status input to provide proof the supply fan is  
operating. When enabled, a loss or lack of fan status will stop heating and cooling operation.  
A Supply Fan Alarm Service Timer function is available to track the number of supply fan run hours and  
generate an alarm when the accumulated runtime exceeds the set threshold.  
Cooling  
The RTU Open's application and configuration determines the specific cooling sequence. The RTU Open can  
control up to two stages of cooling with an additional output for a reversing valve (heat pump applications).  
The following conditions must be true for the cooling algorithm to operate:  
Outdoor Air Temperature is greater than the Cooling Lockout Temperature setpoint  
The indoor fan has been on for at least 30 seconds  
The unit has a valid Supply Air Temperature input  
The unit has a valid Space Temperature input  
Heat mode is not active and the time guard between modes has expired  
Economizer is active and open > 85% with SAT > (Minimum Cooling SAT + 5°F) and SPT > Effective  
Cooling Setpoint + 0.5°F, or the Economizer is unavailable  
RTU Open  
43  
 
Sequence of Operation  
The cooling relays are controlled by the Cooling Control PID Loop and Cooling Stages Capacity algorithm. They  
calculate the desired number of stages needed to satisfy the space by comparing the Space Temperature to  
the:  
Effective Occupied Cooling Setpoint when occupied  
Effective Unoccupied Cooling Setpoint when unoccupied  
When the cooling algorithm preconditions have been met, the compressors are energized in stages, as  
applicable. Anti-recycle timers are employed to protect the equipment from short-cycling. There are fixed  
three-minute minimum on-times, and five-minute off-times for each compressor output.  
During compressor operation, the RTU Open may reduce the number of active stages if the rooftop supply air  
temperature falls below the Minimum Cooling SAT Setpoint. A compressor staged off in this fashion may be  
started again after the normal time-guard period has expired, if the Supply Air Temperature has increased  
above the Minimum Cooling SAT Setpoint.  
Compressor 2 Service Alarm Timer functions are available (one for each stage of compression). This function  
tracks the number of compressor run hours and generates an alarm when the accumulated runtime exceeds  
the threshold set by the adjustable compressor service alarm timers.  
Economizer  
The RTU Open provides an analog economizer output for rooftop units with economizer dampers. Economizer  
dampers may be used to provide free cooling and indoor air quality control when outside air conditions are  
suitable.  
The following conditions must be true for economizer operation:  
The Outdoor Air Temperature is less than the Space Temperature and less than the Economizer High  
OAT Lockout Temp setpoint  
The indoor fan has been on for at least 30 seconds  
The unit has a valid Supply Air Temperature input  
The unit has a valid Space Temperature input  
If any of the preceding conditions are not true, the economizer will be set to the Vent Dmpr Pos / DCV Min  
Pos setpoint.  
If all preceding conditions are true, the economizer PID loop will modulate the damper from the Vent Dmpr  
Pos / DCV Min Pos setpoint.  
The economizer moves to the Vent Dmpr Pos / DCV Min Pos setpoint if the SAT falls below the Minimum  
Cooling SAT (+ 5°F).  
Power Exhaust  
The RTU Open may enable and disable an exhaust fan, based on either the controller’s occupancy or its  
economizer damper position.  
If Continuous Occupied Exhaust is Yes, the Power Exhaust binary output (BO-8) is energized while theRTU  
Open is occupied and de-energized when unoccupied.  
If Continuous Occupied Exhaust is No, the Power Exhaust binary output (BO-8) is energized when the  
economizer damper output exceeds the Power Exhaust Setpoint value (default = 50%). The output remains  
energized until the economizer output falls below the Power Exhaust Setpoint value by a fixed hysteresis of  
10%.  
44  
RTU Open  
Unoccupied Free Cooling  
Unocc Free Cool Enable allows rooftop equipment with an economizer damper to utilize outdoor air for free  
cooling during unoccupied periods.  
The following conditions must be true for unoccupied free cooling to operate:  
Unocc Free Cool Enable set to Enable  
The system is unoccupied  
The outside air temperature is below the Economizer High OAT Lockout Temp setpoint  
The outside air temperature is less than the space temperature  
Enthalpy (if enabled) is Low  
When the RTU Open schedule is unoccupied and the space temperature rises at least 1° above the Occupied  
Cooling Setpoint, the supply fan starts. The economizer damper opens as necessary to cool the space. The  
RTU Open continues to operate in this mode until the space is satisfied or the outside air conditions are no  
longer suitable for free cooling.  
Optimal Start  
The RTU Open may utilize Optimal Start. Optimal Start adjusts the effective setpoints to achieve the occupied  
setpoints by the time scheduled occupancy begins.The Optimal Start recovery period may begin as early as 4  
hours prior to occupancy. The algorithm works by moving the unoccupied setpoints toward the occupied  
setpoints. The rate at which the setpoints move is based on the outside air temperature, design  
temperatures, and capacities.  
The following conditions must be true for unoccupied free cooling to operate:  
On the Properties page > Equipment tab > Configuration > Setpoints > Optimal Start, the Default Value  
must be set greater than 0 and less than or equal to 4 (0.00 disables Optimal Start).  
The system is unoccupied  
NOTE If the Open controller does not have a valid outside air temperature, then a constant of 65° F is used.  
This value is not adjustable.  
RTU Open  
45  
Sequence of Operation  
The actual equation that the controller uses to calculate Optimal Start is nonlinear. An approximation of the  
result is shown below.  
To change Optimal Start settings:  
1
2
In the navigation tree, select the equipment that you want to change.  
Click Properties page > Equipment tab > Configuration > Setpoints.  
Enthalpy control  
You may use an enthalpy switch to indicate the suitability of outdoor air for economizer cooling. You can use  
either an outdoor air or differential enthalpy switch. A differential enthalpy switch has a sensing device in both  
the outdoor and return air streams. A differential enthalpy switch indicates when outside air is cooler than the  
return air, and is available for economizer cooling. If no enthalpy switch is configured, a network point (Object  
Name: oae) is available. This point is displayed in i-Vu and BACview as Enthalpy (BACnet).  
The sequence of operation for economizer cooling is the same with or without an enthalpy switch, except that  
an enthalpy switch imposes one more validation on the suitability of outside air for economizer cooling. An  
Enthalpy Status that is High disables the economizer and the outside air damper goes to its minimum  
position. An Enthalpy Status that is Low enables the economizer if a call for cooling exists and the remaining  
preconditions are met.  
Indoor Air CO2  
Indoor Air CO2 is controlled on rooftop equipment with an economizer. Indoor Air CO2 sequence is enabled  
by installing an air quality (CO2) sensor. A CO2 sensor may be terminated at the RTU Open, or a subordinate  
zone controller, when part of a zoned system.  
An outdoor air quality sensor may also be installed and terminated at the RTU Open, but it is not required.  
When an outdoor air quality sensor is not installed, the algorithm uses 400ppm as the fixed outdoor air CO2  
level.  
46  
RTU Open  
The following conditions must be true for the Indoor Air CO2 algorithm to operate:  
The system is occupied  
The supply fan has been started for at least 30 seconds  
The CO2 sensor has a valid reading  
As the air quality within the space changes, the minimum position of the economizer damper changes, which  
allows more or less outdoor air into the space, depending on the relationship of the indoor air CO2 level to the  
differential setpoint.  
The Indoor Air CO2 algorithm calculates a minimum position value using a PID loop. The CO2 minimum  
damper position is then compared against the Vent Dmpr Pos / DCV Min Pos setpoint and the greatest value  
becomes the final minimum damper position of the economizer output.  
The degree to which the outside air damper may be opened by the Indoor Air CO2 algorithm is limited by the  
DCV Max Vent Damper Pos setpoint, which is adjustable between ten and sixty percent (10 – 60%).  
Heating  
The specific heating sequence is determined by the controller's application and configuration. The RTU Open  
controls up to two stages of gas or electric heating with an additional output for a Reversing Valve (Heat  
Pump applications).  
The following conditions must be true for the heating algorithm to operate:  
The Outdoor Air Temperature is less than the Heating Lockout Temperature setpoint  
The indoor fan has been ON for at least 30 seconds  
The unit has a valid Supply Air Temperature input  
The unit has a valid Space Temperature input  
Neither Cool mode nor economizer are active and the time guard between modes has expired  
The heating relays are controlled by the Heating Control PID Loop and Heating Stages Capacity algorithm,  
which calculate the desired number of stages to satisfy the space by comparing the Space Temperature to  
the:  
Effective Occupied Heating Setpoint when occupied  
Effective Unoccupied Heating Setpoint when unoccupied  
When the heating algorithm preconditions have been met, the heating is energized in stages. Anti-recycle  
timers are employed to protect the equipment from short-cycling. There are fixed one minute minimum on  
and off times for each heating output.  
During heating operation, the RTU Open may reduce the number of active stages if the rooftop Supply Air  
Temperature exceeds the Maximum Heating SAT setpoint. A heat stage turned off in this fashion may be  
started again after the normal time-guard period has expired, if the Supply Air Temperature has decreased  
below the Maximum Heating SAT setpoint.  
RTU Open  
47  
 
Sequence of Operation  
Heat Pump operation  
The RTU Open can control heat pumps HP O/B and Y1/W1.  
HP O/B provides a separate output (BO-7) to control a reversing valve. The reversing valve control may be  
configured to be energized with a call for heating (B), or energized with a call for cooling (O).  
The sequence of operations are as previously described for heating and cooling except that the Y1 and Y2  
outputs are compressor outputs, energizing mechanical heating or cooling, depending on the state of the  
reversing valve. W1 and W2 are used for auxiliary heat. Up to two stages are available.  
Selection Y1/W1 is for heat pumps that do not require a O terminal to energize the reversing valve. The  
sequences of operations are as described for Heating (page 47) and Cooling (page 43). The reversing valve  
output is not utilized in this application. W1 and W2 are used for auxiliary heat. Up to two stages are  
available.  
Dehumidification  
The RTU Open provides occupied and unoccupied dehumidification on units that are equipped with the  
Carrier Humidi-MiZer™ option from the factory. This requires a space relative humidity sensor or a humidistat  
for control.  
The following conditions must be true for the dehumidification control to operate:  
The Outside Air Temperature is greater than the Cooling Lockout Temperature setpoint  
The Indoor Fan has been ON for at least 30 seconds  
The unit has a valid Supply Air Temperature input  
The unit has a valid Space Temperature input  
The unit has a valid Space Relative Humidity Sensor or Humidistat input  
Heat mode is not active and the time guard between modes has expired  
When using a relative humidity sensor to control dehumidification, occupied and unoccupied dehumidification  
setpoints are used.  
When using a humidistat, the setpoints are not used. The humidistat indicates a high-humidity condition.  
When a high indoor relative humidity condition is indicated and the above conditions are satisfied, the RTU  
Open enters the dehumidification mode, energizing the Humidi-MiZer™ output.  
The mode continues until the space relative humidity falls below the active setpoint by a 5% fixed Hysteresis  
when a humidity sensor is used, or when there is no longer a call for dehumidification where a humidistat is  
used.  
See the base unit / Humidi-MiZer™ operations manual for additional information.  
48  
RTU Open  
 
Demand Limit  
The RTU Open may employ a demand limit strategy. Demand limiting in the RTU Open works through setpoint  
expansion. The controller’s heating and cooling setpoints are expanded in steps or levels. The degree to  
which the setpoints are expanded is defined by the Demand Level Setpoints.  
Each Demand Level (1 through 3) adjusts the heating and cooling setpoints outwards. By default, Demand 1  
yields a 1° expansion, Demand 2 yields a 2° expansion, and Demand 3 yields a 4° expansion.  
The BACnet Demand Limit variable sets the desired level of setpoint expansion in the receiving controller.  
Level 0 leaves the standard occupied and unoccupied heating and cooling setpoints in effect. Levels 1  
through 3 expands occupied heating and cooling setpoints.  
Door switch  
A Door Contact may be configured on any unused binary input. A typical application is an occupancy sensor  
mounted within the space served by a single zone rooftop. Door Contact disables mechanical cooling and  
electric or gas heating, when active. Economizer cooling, if available, continues to operate.  
Remote occupancy  
Remote occupancy may be configured on any unused binary input channel. A typical application is a remote  
contact, controlled by a third party, to set the controller's occupied mode. The Remote Occupancy function  
requires both an input configured for Remote Occupancy, and Occupancy Source set to Remote Occ Input to  
operate.  
Once configured, the controller will operate in the occupied or unoccupied mode, as determined by the state  
of the Remote Occupancy input.  
Fire Shutdown  
Fire Shutdown may be configured on Binary Input 5. A typical application involves a smoke detector or fire  
shutdown contact, which, when active, immediately shuts down equipment operation.  
Compressor Safety  
Compressor Safety may be configured on Binary Input 3. A compressor safety tripped indicator circuit is  
available on most Carrier rooftop equipment.  
A Compressor Safety Alarm is shown on Properties page > Equipment tab > Alarms and indicates that the  
equipment requires attention.  
RTU Open  
49  
Sequence of Operation  
Cooling, heating, and supply fan outputs are not interrupted except where the RTU Open is configured for  
Heat Pump operation. When configured for Heat Pump, and in the heating mode, a compressor safety fault  
will cause the available stages of electric heating to be enabled in place of mechanical heating.  
Normal operation resumes when the compressor safety circuit is de-energized.  
Fan Status  
Fan Status may be configured on any unused binary input channel. A typical application would be an airflow  
switch, current sensing relay, or other device that provides a supply fan running verification.  
Enabling this function displays the supply fan’s status on the equipment graphic.  
If the controller loses fan status during operation, heating and cooling are disabled, the economizer damper  
(if available) is closed, and an alarm for loss of status is indicated.  
If the fan status is on when the controller is commanding the fan off, the unit remains in the off state. An  
alarm is generated indicating that the fan is running when it should be off.  
Filter Status  
Filter status may be configured on any unused binary input channel. A typical application is a differential  
pressure switch that senses the pressure drop across a filter bank.  
When the pressure across the filter bank exceeds the setpoint of the differential pressure switch, the Filter  
status is displayed as Dirty on the controller graphic. An alarm indicates a dirty filter.  
Alarms  
NOTE Some of the Alarms functions described in this section will only be visible on the Properties page >  
Equipment tab > Alarms when the appropriate inputs are configured. Alarms are not initiated when the input  
is not configured.  
Safety Chain - You may use the RTU Open's safety chain circuit to shut down the unit for a safety condition.  
Examples: Low or High Temperature Cutouts (Freezestat / Firestat). See To wire inputs and outputs (page 14)  
for additional wiring instructions. This alarm indicates the safety chain circuit (Input 4) is open. Cooling,  
heating, and supply fan operation stop after appropriate time guards. Normal operation resumes when the  
safety chain circuit is complete.  
Fire Shutdown – You may configure the RTU Open to accept a Fire Shutdown contact on Input 5. Examples:  
Smoke detectors or fire shutdown relays. This alarm indicates this device (Input 5) has tripped. Cooling,  
heating, and supply fan operation immediately stop. Reset fire shutdown contact to resume normal operation.  
Compressor Safety – You may configure the RTU Open to monitor the base unit’s compressor safety circuit.  
This alarm indicates the base unit's compressor safety circuit is energized. Cooling, heating, and supply fan  
outputs are not interrupted except when the RTU Open is configured for Heat Pump. Normal operation  
resumes when the compressor safety circuit is de-energized.  
If the Heat Pump is in the heating mode, it will automatically replace the compressor stage(s) with the  
equivalent number of auxiliary heat stages, as available.  
If it's a Carrier Heat Pump, there is only one auxiliary heat stage output and the staging is done by the  
machine itself, if it's two-stage gas or electric.  
50  
RTU Open  
For a non-Carrier Heat Pump, when configured for two stages of aux heat and two compressors,  
Compressor 1 is replaced by Aux Heat Stage 1 and Compressor 2 is replaced by Aux Heat Stage 2.  
The compressor output stays on when the safety alarm is present. For cooling, the alarm indicates the  
compressors are down. See Heat Pump operation (page 48) for further information.  
Space Temp Sensor – This alarm indicates an invalid sensor condition in a physically connected space  
temperature sensor (SPT Sensor/T5*). Cooling, heating, and supply fan operation stop after the appropriate  
time guards. Normal operation resumes when the controller detects a valid sensor.  
Supply Air Temp Sensor – This alarm indicates a shorted or open circuit in the SAT input. Cooling, heating,  
and supply fan operation stops after the appropriate time guards. Normal operation resumes when the  
controller detects a valid sensor.  
Outdoor Air Temp Sensor Alarm - This alarm indicates a shorted or open circuit in the OAT input. Cooling,  
heating, and supply fan operation continues. OAT lockouts will not operate while the sensor is in alarm.  
Normal operation resumes when the controller detects a valid sensor.  
Space Relative Humidity Sensor - This alarm indicates if the mA input at the associated channel falls below  
3.5 mA or rises above 21 mA. Cooling, heating, and supply fan operation continues, however, the controller’s  
Humidi-MiZer™ binary output is disabled until the fault condition is corrected.  
IAQ Sensor - The RTU Open generates an IAQ Sensor alarm if the mA input at the associated channel falls  
below 3.5 mA or rises above 21 mA. Cooling, heating, and supply fan operation continues. However, the  
controller’s IAQ control function is disabled until the fault condition is corrected.  
OAQ Sensor - The RTU Open generates an OAQ Sensor alarm if the mA input at the associated channel falls  
below 3.5 mA or rises above 21 mA. Cooling, heating, and supply fan operation continues. However, the  
controller’s IAQ control function uses 400ppm as the fixed outdoor air CO2 level until the fault condition is  
corrected.  
Space Temperature –  
Occupied - The RTU Open generates a Low Space Temperature alarm if the space temperature falls  
below the lower limit of the blue color bar. A High Space Temperature alarm is generated if the space  
temperature rises above the upper limit of the orange color bar.  
Unoccupied An unoccupied low space temperature alarm is generated when the space temperature falls  
below the Alarm Configuration > Unoccupied Low SPT Alarm Limit. An unoccupied high space  
temperature alarm is generated when the space temperature rises above the Alarm Configuration >  
Unoccupied High SPT Alarm Limit.  
The following values are related to the Space Temperature alarm:  
Alarming Temperature – This variable displays the value of the space temperature that is in alarm and is  
only visible when the space temperature is in an alarm state.  
Alarm Limit Exceeded – This variable displays the value of the alarm setpoint that is exceeded by the  
alarming space temperature and is only visible when the space temperature is in an alarm state.  
High Supply Air Temperature – The RTU Open generates this alarm when the supply air temperature exceeds  
the Alarm Configuration > High SAT Alarm Limit setpoint for 5 minutes. This alarm is inhibited until the RTU  
has been running for 30 minutes to allow for system stabilization after startup.  
Low Supply Air Temperature - The RTU Open generates this alarm when the supply air temperature falls  
below the Alarm Configuration > Low SAT Alarm Limit setpoint for 5 minutes. This alarm is inhibited until the  
RTU has been running for 30 minutes to allow for system stabilization after startup.  
Setpoint Slider – The RTU Open generates this alarm when an open circuit is detected at Input 11 and the  
RTU Open Configuration > Unit Configuration > Input Configuration > Space sensor type is set to T56. Note  
that only an open circuit results in an alarm. A short across this input offsets the setpoints negatively by the  
amount configured in the Unit Configuration > Setpoint Adjustment Range.  
Switch Configuration - The RTU Open generates this alarm when any two of the Unit Configuration > Input  
Functions 3, 5, 8, or 9 are configured identically. Neither input may work reliably and downstream control may  
be affected, depending on the function duplicated. The alarm clears and normal control is restored when the  
input function duplication is corrected.  
Analog Input Configuration - The RTU Open generates this alarm when the Unit Configuration > Input  
RTU Open  
51  
Sequence of Operation  
Functions 1 and 2 are configured identically. Neither input may work reliably and downstream control may be  
affected, depending on the function duplicated. The alarm clears and normal control is restored when the  
input function duplication is corrected.  
High Space Relative Humidity - The RTU Open generates this alarm when the space humidity exceeds the  
Alarm Configuration > High Space Humidity Alarm Limit setpoint for 10 minutes. This alarm is inhibited until  
the RTU runs for 15 minutes to allow for system stabilization after startup.  
Low Space Relative Humidity - The RTU Open generates this alarm when the space humidity falls below the  
Alarm Configuration > Low Space Humidity Alarm Limit setpoint for 5 minutes. This alarm is inhibited until  
the RTU runs for 5 minutes to allow for system stabilization after startup.  
High CO2 - The RTU Open generates this alarm when the space CO2 level exceeds the Alarm Configuration >  
Occupied High CO2 Alarm Limit setpoint for 1-minute. This alarm will be inhibited until the RTU has been  
running for 2-minutes to allow for system stabilization after startup.  
Supply Fan Runtime - The RTU Open generates a this alarm when the accumulated runtime exceeds the Unit  
Configuration > Supply Fan Service Alarm Timer value (when not set to 0). This alarm is most commonly  
used to indicate an equipment maintenance interval is due. The supply fan runtime accumulator may be reset  
by setting the Maintenance > Reset Supply Fan Runtime Alarm to Clear, and then back to Run –  
acknowledging each selection by clicking the OK button when it appears. Setting Unit Configuration > Supply  
Fan Service Timer value to 0 disables the supply fan runtime alarm function.  
Compressor 1 Runtime - The RTU Open generates this alarm when the accumulated runtime exceeds the  
Unit Configuration > Compressor 1 Service Alarm Timer value (when not set to 0). This alarm is most  
commonly used to indicate an equipment maintenance interval is due. The Compressor 1 Runtime  
accumulator may be reset by setting the Maintenance > Reset Comp 1 Runtime Alarm to Clear, and then  
back to Run – acknowledging each selection by clicking the OK button when it appears. Setting Unit  
Configuration > Compressor 1 Service Timer value to 0 disables the Compressor 1 Runtime alarm function.  
Compressor 2 Runtime - The RTU Open generates this alarm when the accumulated runtime exceeds the  
Unit Configuration > Compressor 2 Service Alarm Timer value (when not set to 0). This alarm is most  
commonly used to indicate an equipment maintenance interval is due. The Compressor 2 runtime  
accumulator may be reset by setting the Maintenance > Reset Comp 2 Runtime Alarm to Clear, and then  
back to Run – acknowledging each selection by clicking the OK button when it appears. Setting Unit  
Configuration > Compressor 2 Service Timer value to 0 disables the Compressor 2 runtime alarm function.  
Note that this function is unavailable if the Service Configuration > Compressor States value is not set to Two  
Stages.  
Filter - The RTU Open generates this alarm when the accumulated runtime exceeds the Unit Configuration >  
Filter Service Alarm Timer value (when not set to 0). This alarm is most commonly used to indicate a filter  
replacement is due. Reset the filter service runtime accumulator by setting the Maintenance > Reset Filter  
Runtime Alarm to On, back to Off, and clicking the OK button after each setting. Setting Unit Configuration >  
Filter Service Alarm Timer value to 0 disables the filter service alarm function.  
Airside Linkage Alarm - An RTU Open may act as an air source in a zoned system. Carrier systems utilize a  
function called Linkage™ to pass data between a master zone and its air source via an MS/TP network  
connection. When the RTU Open is part of a linked system, it will indicate an airside linkage alarm if it loses  
communications with its linkage master or if it receives invalid data.  
52  
RTU Open  
Linkage  
The RTU Open may serve as an air source to an Open Variable Volume Terminal (VVT) system. When the RTU  
Open is part of a VVT system and the controllers are wired together to form a network, the controllers may use  
a method of communication known as Linkage™. Linkage is a method by which an air source and its  
subordinate zone terminals exchange data to form a coordinated HVAC system. The system's air source  
controller, zone controllers, and bypass controller are linked so that their data exchange can be managed by  
one zone controller configured as the VVT Master.  
The VVT Master gathers the following information from the slave zone controllers:  
occupancy status  
setpoints  
zone temperature  
relative humidity  
CO2 level  
damper position  
optimal start data  
The VVT Master performs mathematical calculations and algorithms on the data and then sends the  
composite information to the air source. The VVT Master receives information from the air source such as  
mode, supply air temperature, and outside air temperature, and passes that information to all linked  
controllers.  
NOTE The following paragraphs describe the interaction between the air source (RTU Open) and its  
subordinate zones. Additional information regarding Open Zoned Systems may be found in the VVT Zone and  
VVT Bypass Controller Installation Guides.  
The VVT Master determines system operation by prioritizing heating and cooling requirements from all the  
zones based on their occupancy and demand. The VVT Master scans the system continuously to determine if  
any zones are occupied. Occupied zones are a higher priority than unoccupied zones. The VVT Master  
evaluates all the occupied zones' heating or cooling demands and sends a request to the air source (RTU  
Open) for:  
Cooling, if the number of occupied zones with cooling demands exceeds the number of occupied zones  
with heating demands, and the demand is greater than or equal to the number of configured Linkage  
Callers.  
Heating, if the number of occupied zones with a heating demand exceeds or is equal to the number of  
Linkage Callers.  
If no zones are occupied or no occupied zones require heating or cooling, the VVT Master performs the  
evaluation described above for the unoccupied zones.  
The VVT Master then gathers the following information and sends it to the air source (RTU Open):  
The system mode  
The setpoints and zone temperature from the zone with the greatest demand for the requested air  
source mode (heating or cooling). (This zone is called the reference zone.)  
The system occupancy status  
Most open damper position from any zone  
RH and CO2 values (if applicable)  
The air source responds by sending the air source mode, supply air temperature, and outside air temperature.  
The air source verifies the mode by comparing its supply air temperature to the space temperature received  
through Linkage. See the air source documentation for operation and parameters used to verify its mode.  
This verification allows the VVT system to determine if the desired air source mode is actually being provided.  
For example, if the VVT Master sends a request for heating and the air source does not have heat or it’s heat  
has failed, the air source's actual mode indicates that and it's current mode is sent to the zones so that they  
can control accordingly.  
RTU Open  
53  
Sequence of Operation  
The system remains in that mode until all zones of that demand are satisfied or until a fixed 30 minute mode  
reselect timer causes a forced re-evaluation of the system. If there is no demand for the opposite mode, the  
reselect timer starts again and the current mode continues until all zones are satisfied or until the reselect  
timer expires, repeating the process. If there is a demand for the opposite mode, the VVT Master sends the  
reference zone's space temperature and setpoints to the air source and restarts the reselect timer. The air  
source re-evaluates its demand based on the new information and goes to the Vent mode until the new mode  
can be verified as described above. The amount of time this takes is determined by the air source’s operating  
parameters.  
The VVT Master continuously evaluates the system and updates the air source with the most current system  
demand. Based on the evaluation, the reference zone can change from one zone to another. The evaluation  
process continues until there is no demand from any zone or the 30 minute timer causes a re-evaluation of  
the system conditions.  
If no heating or cooling is required or the current air source mode is satisfied, the VVT Master calculates the  
weighted average of the occupied and unoccupied heating and cooling setpoints. It also calculates a zone  
temperature that is midway between the setpoints (occupied or unoccupied based on the system’s current  
occupancy status). This information, plus the occupancy status, is sent to the air source so that its current  
mode is disabled and the unit ceases heating or cooling operation. If the system is occupied, the air source  
fan and OA damper, if applicable, operate to maintain proper ventilation.  
Linkage Air Source Modes  
In a linked system, the air source determines its operating mode and qualifies that mode based on its own  
Supply Air Temperature (SAT). The following modes can be sent by the air source depending on its  
configuration:  
Off – Air source fan is off  
Fan Only – Air source fan is on and providing ventilation (neutral SAT) without heating or cooling  
Economizer Cooling – Air source fan is on and providing cooling, using economizer only  
Cooling – Air source fan is on and cooling is provided by economizer and mechanical cooling  
Heating – Air source fan is on and heating is provided (gas or electric)  
Dehumidification – Air source fan is on and Humidi-MiZer™ is active  
Test – The RTU Open Service Test mode is active  
Shutdown – Air source fan is off due to Safety Chain, Fire Shutdown, or invalid SAT sensor  
Unocc Free Cooling – Air source fan is on, with the economizer providing cooling while unoccupied  
54  
RTU Open  
Troubleshooting  
If you have problems mounting, wiring, or addressing the RTU Open, contact Carrier Control Systems Support.  
Serial number  
If you need the RTU Open's serial number when troubleshooting, the number is on:  
a sticker on the back of the main controller board  
a Module Status report (modstat) from your user interface  
LED's  
The LED's on the RTU Open show the status of certain functions.  
If this LED is on...  
Status is...  
Power  
Rx  
The RTU Open has power  
The RTU Open is receiving data from the network segment  
The RTU Open is transmitting data over the network segment  
The binary output is active  
Tx  
DO#  
The Run and Error LED's indicate controller and network status.  
If Run LED shows...  
2 flashes per second  
2 flashes per second  
And Error LED shows...  
Status is..  
Off  
Normal  
2 flashes,  
alternating with Run LED  
Five minute auto-restart delay  
after system error  
2 flashes per second  
2 flashes per second  
5 flashes per second  
7 flashes per second  
3 flashes, then off  
The controller has just been  
formatted  
On  
Off  
Exec halted after frequent system  
errors or control programs halted  
Firmware transfer in progress,  
Boot is running  
7 flashes per second,  
alternating with Run LED  
Ten second recovery period after  
brownout  
RTU Open  
55  
Troubleshooting  
If Run LED shows...  
And Error LED shows...  
Status is..  
14 flashes per second  
14 flashes per second,  
alternating with Run LED  
Brownout  
On  
On  
Failure. Try the following solutions:  
Turn the RTU Open off, then  
on.  
Format the RTU Open.*  
Download memory to the RTU  
Open.  
Replace the RTU Open.  
*Formatting the controller may result in lost information and should only be done under the guidance of  
Carrier Control Systems Support.  
Replacing the RTU Open's battery  
The RTU Open's 10-year Lithium CR2032 battery provides a minimum of 10,000 hours of data retention  
during power outages.  
CAUTION Power must be ON to the RTU Open when replacing the battery, or your date, time, and trend data  
will be lost.  
1
2
Remove the battery from the controller, making note of the battery's polarity.  
Insert the new battery, matching the battery's polarity with the polarity indicated on the RTU Open.  
56  
RTU Open  
Compliance  
FCC Compliance  
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to  
Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful  
interference when the equipment is operated in a commercial environment. This equipment generates, uses,  
and can radiate radio frequency energy and, if not installed and used in accordance with the instruction  
manual, may cause harmful interference to radio communications. Operation of this equipment in a  
residential area is likely to cause harmful interference in which case the user will be required to correct the  
interference at his own expense.  
CAUTION Changes or modifications not expressly approved by the responsible party for compliance could  
void the user’s authority to operate the equipment.  
CE Compliance  
WARNING This is a Class A product. In a domestic environment, this product may cause radio interference in  
which case the user may be required to take adequate measures.  
BACnet Compliance  
BACnet® is a registered trademark of ASHRAE. ASHRAE does not endorse, approve or test products for  
compliance with ASHRAE standards. Compliance of listed products to requirements of ASHRAE Standard 135  
is the responsibility of the BACnet manufacturers Association (BMA). BTL® is a registered trademark of the  
BMA.  
RTU Open  
57  
Appendix A: RTU Open Points/Properties  
Appendix A: RTU Open Points/Properties  
Status  
Navigation:  
i-Vu / Field Assistant:  
BACview:  
Properties > Equipment > Status  
HOME > STATUS  
Point Name/Description  
Range  
System Mode – The controller's current operating status.  
R:  
Disabled  
Test  
Run  
Operating Mode – The controller's current operating mode.  
R:  
Off  
Fan Only  
Economizer  
Cooling  
Heating  
Dehumidification  
Test  
Shutdown  
Unocc Free Cooling (NTFC)  
Supply Fan Status – The current fan status if an input is configured for Fan Status.  
R:  
R:  
Off/Running  
-56 to 245°F  
Space Temperature - Prime Variable – The space temperature value currently used for  
control.  
Supply Air Temperature – The current supply air temperature.  
R:  
R:  
R:  
-56 to 245°F  
-56 to 245°F  
0 to 100%rh  
Outdoor Air Temperature – The outdoor air temperature value used for control.  
Space Relative Humidity – The current space relative humidity if Configuration > Unit  
Configuration > Input 1 (or 2) Function is set to Space RH Sensor.  
R:  
R:  
R:  
0 to 5000ppm  
0 to 5000ppm  
0 to 100% Open  
Indoor Air CO2 – The current indoor air CO2 concentration if the Configuration >Unit  
Configuration > Input 1 (or 2) Function is set to IAQ Sensor.  
Outdoor Air CO2 – The current outdoor air CO2 concentration if the Configuration >Unit  
Configuration >Input 1 (or 2) Function is set to OAQ Sensor.  
Economizer Output – The current economizer output with respect to the outdoor air  
damper (if equipped).  
58  
RTU Open  
 
Unit Configuration  
Navigation:  
i-Vu / Field Assistant:  
BACview:  
Properties > Equipment > Configuration > Unit Configuration  
HOME > CONFIG > UNIT  
Point Name/Description  
Default/Range  
Fan Mode – The supply fan's operating mode.  
D:  
R:  
Continuous  
Options:  
Auto  
Auto - The fan cycles on/off in conjunction with heating or cooling.  
Continuous - The fan runs continuously during occupancy & intermittently during  
unoccupied periods with heating or cooling.  
Continuous  
Always On  
Always On - The fan runs continuously regardless of occupancy or calls for heating and  
cooling.  
Unit Start Delay – The amount of time the controller delays starting up after receiving a  
start command.  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
5 sec  
0 to 30 sec  
90 sec  
Fan Off Delay – How long the supply fan runs after receiving a valid stop command.  
0 to 180 sec  
50°F  
Minimum Cooling SAT – In cooling mode, the cooling outputs are controlled so that the  
supply air temperature does not drop below this value.  
45 to 75°F  
120°F  
Maximum Heating SAT – In heating mode, the heating outputs are controlled so the  
supply air temperature does not rise above this value.  
85 to 150°F  
50% Open  
0 to 100% Open  
50% Open  
10 to 60% Open  
600 hr  
Vent Dmpr Pos / DCV Min Pos – The minimum outdoor air damper position maintained  
during occupied periods.  
DCV Max Vent Damper Pos – The maximum outdoor air damper position allowed while  
DCV is active.  
Supply Fan Service Alarm Timer – A Supply Fan Runtime alarm is generated when the  
supply fan run hours exceed this value. Set to 0 to disable.  
0 to 9999 hr  
0 hr  
Compressor 1 Service Alarm Timer – A Compressor 1 Runtime alarm is generated when D:  
the compressor 1 run hours exceed this value. Set to 0 to disable.  
R:  
0 to 9999 hr  
0 hr  
Compressor 2 Service Alarm Timer – A Compressor 2 Runtime alarm is generated when D:  
the compressor 2 run hours exceed this value. Set to 0 to disable.  
R:  
0 to 9999 hr  
600 hr  
Filter Service Alarm Timer – The amount of time the fan will run before generating a  
Filter Alarm. Set to 0 to disable the alarm and reset accumulated fan hours.  
D:  
R:  
0 to 9999 hr  
Enable  
Pushbutton Override – Enables or disables the use of a pushbutton override from a local D:  
space temperature sensor.  
R:  
Disable/Enable  
45°F  
Cooling Lockout Temp – The outdoor air temperature at which cooling is inhibited.  
D:  
R:  
D:  
R:  
0 to 80°F  
75°F  
Economizer High OAT Lockout – The outdoor air temperature at which economizer  
cooling is inhibited.  
55 to 80°F  
RTU Open  
59  
 
Appendix A: RTU Open Points/Properties  
Point Name/Description  
Default/Range  
HP Rev Cycle Lockout Temp – The outdoor air temperature at which reverse cycle  
heating is locked out. Requires that the unit is configured as a Heat Pump.  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
-3°F  
-20 to 30°F  
65°F  
Heating Lockout Temperature – The outdoor air temperature at which heating is  
inhibited.  
35 to 150°F  
Disable  
Unocc Free Cool Enable – Enable to allow the unit to use economizer to provide  
unoccupied free cooling (NTFC).  
Disable/Enable  
Always Occupied  
Occupancy Source - The method that the controller uses to determine occupancy.  
Options:  
Always Occupied  
BACnet Schedule  
BAS On/Off  
Always Occupied = Controller operates continuously as occupied.  
BACnet Schedule = Controller follows a schedule set up in i-Vu or Field Assistant.  
BAS On/Off = Occupancy is set over the network by another device or a third party BAS.  
Remote Occ Input =Occupancy is set by a remote contact.  
Remote Occ Input  
Input Configuration  
Input 1 Function – The type of sensor (4-20 mA) connected to terminals J4 – 4, 5, & 6.  
D:  
R:  
No Sensor  
No Sensor  
IAQ Sensor  
OAQ Sensor  
Space RH Sensor  
Input 2 Function – The type of sensor (4-20 mA) connected to terminals J4 – 1, 2, & 3.  
D:  
R:  
No Sensor  
No Sensor  
IAQ Sensor  
OAQ Sensor  
Space RH Sensor  
Input 3 Function – The usage of Input 3. You must also set Input 3 Switch Configuration. D:  
Compressor Safety  
Options:  
R:  
No Function  
Compressor Safety  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
No Function – The input is not used.  
Compressor Safety – Safety device status.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 3 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Input 5 Function – The usage of Input 5. You must also set Input 5 Switch Configuration. D:  
Fire Shutdown  
Options:  
R:  
No Function  
Fire Shutdown  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
No Function – The input is not used.  
Fire Shutdown – Fire Safety device status. Inhibits operation when tripped.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 5 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NC  
NO/NC (normally  
open/normally closed)  
60  
RTU Open  
Point Name/Description  
Default/Range  
Input 8 Function – The usage of Input 8. You must also set Input 8 Switch Configuration. D:  
Enthalpy Switch  
Options:  
R:  
No Function  
Enthalpy Switch  
No Function – The input is not used.  
Enthalpy Switch – Indicates enthalpy status (high or low).  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
Input 8 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Input 9 Function – The usage of Input 9. You must also set Input 9 Switch Configuration. D:  
Humidistat  
Options:  
R:  
No Function  
Humidistat  
No Function – The input is not used.  
Humidistat – Indicates high humidity condition.  
Fan Status – Proves supply fan operation.  
Filter Status – Indicates a dirty filter.  
Fan Status  
Filter Status  
Remote Occupancy  
Door Contact  
Remote Occupancy – Sets occupancy using a hardware contact.  
Door Contact – Sets occupancy using a hardware contact.  
Input 9 Switch Configuration – The normal (de-energized) state for the set of contacts  
terminated at Input  
D:  
R:  
NO  
NO/NC (normally  
open/normally closed)  
Space sensor type - The type of local space temperature sensor.  
D:  
R:  
T55  
T55  
T56 (Use for T59)  
SPT Sensor  
None  
T5x Override Duration – If using a T55, T56, or T59 sensor, this is the amount of time  
that the controller runs in the occupied mode when a user presses the sensor's override  
button for 1 to 10 seconds.  
D:  
R:  
1 hr  
0 to 24 hours  
Sensor Calibration  
Space Temp Calibration – A calibration offset value to allow the local space temperature D:  
0°F  
sensor to be adjusted to match a calibrated standard measuring the temperature in the  
same location.  
R:  
-9.9 to 10°F  
Supply Air Temp Calibration – A calibration offset value to allow the supply air  
temperature sensor to be adjusted to match a calibrated standard measuring the  
temperature in the same location.  
D:  
R:  
0°F  
-9.9 to 10°F  
Outside Air Temp Calibration – A calibration offset value to allow the outside air  
temperature sensor to be adjusted to match a calibrated standard measuring the  
temperature in the same location.  
D:  
R:  
0°F  
-9.9 to 10°F  
Setpoints  
RTU Open  
61  
Appendix A: RTU Open Points/Properties  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Setpoints  
HOME > CONFIG > SETPOINT  
Select a color band on the setpoint graph to see the current setpoints in the Heating and Cooling fields. See setpoint  
descriptions below.  
Occupied Setpoints  
The occupied setpoints described below are the setpoints under normal operating conditions. The Demand Level 1–3  
setpoints apply if demand limiting is used.  
Demand limiting is a cost-saving strategy to reduce energy consumption. The strategy expands the occupied heating and  
cooling setpoints when the system reaches one of 3 levels of consumption. With the expanded setpoints, the equipment  
works less, thereby saving energy. By default, Demand Level 1 expands the occupied heating and cooling setpoints by 1°F,  
Demand Level 2 by 2°F, and Demand Level 3 by 4°F. If the occupied heating or cooling setpoints change, the (effective)  
demand level setpoints automatically change by the same amount. See Sequence of Operation (page 42) for more  
information.  
Default  
Range: -40 to 245°F  
Demand Level  
Point Name/Description  
Occupied  
1
2
3
Occupied Heating – Green  
The heating setpoint the controller maintains while in occupied mode.  
70°F  
69°F 68°F 66°F  
75°F 76°F 78°F  
68°F 67°F 65°F  
Occupied Cooling – Green  
The cooling setpoint the controller maintains while in occupied mode.  
74°F  
69°F  
Occupied Heating 1 – Light Blue  
The space temperature must be less than the Occupied Heating 1 setpoint for the  
VVT Master to consider the zone a heating caller in a linked system. In a single-  
zone application, the heating requirement begins as soon as the space  
temperature falls below the Occupied Heating setpoint. We recommend that the  
Occupied Heating 1 value be set no less than 0.5°F below the Occupied Heating  
setpoint.  
Occupied Heating 2 – Dark Blue  
68°F  
67°F 66°F 64°F  
The space temperature must be less than the Occupied Heating 2 setpoint to  
generate a low space temperature alarm. We recommend that this value be set no  
less than 0.5°F below the Occupied Heating 1 setpoint.  
62  
RTU Open  
Default  
Range: -40 to 245°F  
Demand Level  
Point Name/Description  
Occupied  
1
2
3
Occupied Cooling 1 – Yellow  
75°F  
76°F 77°F 79°F  
The space temperature must be greater than the Occupied Cooling 1 setpoint for  
the VVT Master to consider the zone a cooling caller in a linked system. In a single-  
zone application, the cooling requirement begins as soon as the space  
temperature exceeds the Occupied Cooling setpoint. We recommend that the  
Occupied Cooling 1 value be set no less than 0.5°F above the Occupied Cooling  
setpoint.  
Occupied Cooling 2 – Orange  
76°F  
78°F 78°F 81°F  
The space temperature must be greater than the Occupied Cooling 2 setpoint to  
generate a high space temperature alarm. We recommend that this value be set  
no less than 0.5°F above the Occupied Cooling 1 setpoint.  
Unoccupied Setpoints  
Point Name/Description  
Default/Range  
Unoccupied Heating – Gray  
The heating setpoint the controller maintains while in unoccupied mode.  
D:  
R:  
D:  
R:  
D:  
R:  
55°F  
45 to 100°F  
90°F  
Unoccupied Cooling – Gray  
The cooling setpoint the controller maintains while in unoccupied mode.  
-40 to 245°F  
54°F  
Unoccupied Heating 1 – Light Blue  
The space temperature must be less than the Unoccupied Heating 1 setpoint for the VVT  
Master to consider the zone an unoccupied heating caller in a linked system. In a single-zone  
application, the unoccupied heating requirement begins as soon as the space temperature falls  
below the Unoccupied Heating setpoint. We recommend that the Unoccupied Heating 1 value  
be set no less than 0.5°F below the Unoccupied Heating setpoint.  
-40 to 245°F  
Unoccupied Heating 2 – Dark Blue  
D:  
R:  
52°F  
The space temperature must be less than the Unoccupied Heating 2 setpoint to generate an  
unoccupied low space temperature alarm. We recommend that this value be set no less than  
0.5°F below the Unoccupied Heating 1 setpoint.  
-40 to 245°F  
Unoccupied Cooling 1 – Yellow  
D:  
R:  
91°F  
The space temperature must be greater than the Unoccupied Cooling 1 setpoint for the VVT  
Master to consider the zone an unoccupied cooling caller in a linked system. In a single-zone  
application, the unoccupied cooling requirement begins as soon as the space temperature  
exceeds the Unoccupied Cooling setpoint. We recommend that the Unoccupied Cooling 1 value  
be set no less than 0.5°F above the Unoccupied Cooling setpoint.  
-40 to 245°F  
Unoccupied Cooling 2 – Orange  
D:  
R:  
93°F  
The space temperature must be greater than the Unoccupied Cooling 2 setpoint to generate an  
unoccupied high space temperature alarm. We recommend that this value be set no less than  
0.5°F above the Unoccupied Cooling 1 setpoint.  
-40 to 245°F  
RTU Open  
63  
Appendix A: RTU Open Points/Properties  
Point Name/Description  
Default/Range  
Heating Capacity – Used for Optimal Start, this is the rate at which the zone temperature  
changes when the heating system runs at full capacity to maintain designed occupied heating  
setpoint.  
D:  
R:  
5°F/hr  
0 to 120°F/hr  
Heating Design Temp – The geographically-based outdoor air temperature at which the heating D:  
0°F  
system must run constantly to maintain comfort. This information is available in ASHRAE  
publications and most design references.  
R:  
-100 to 150°F  
Cooling Capacity – Used for Optimal Start, this is the rate at which the zone temperature  
changes when cooling system runs at full capacity to maintain designed occupied cooling  
setpoint.  
D:  
R:  
5°F/hr  
0 to 140°F/hr  
Cooling Design Temp – The geographically-based outdoor air temperature at which the cooling D:  
100°F  
system must run constantly to maintain comfort. This information is available in ASHRAE  
publications and most design references.  
R:  
-100 to 150°F  
Hysteresis – The desired difference between the temperature at which the zone color changes D:  
0.5°F  
as the zone temperature departs from the acceptable range between the heating and cooling  
setpoints (green) into the Cooling 1 (yellow) or Heating 1 (light blue) and the temperature at  
R:  
0 to 120°F  
which the zone color changes back to the acceptable range between the heating and cooling  
setpoints.  
For example, the following graph shows the zone color that results as the zone temperature  
departs from and returns to the acceptable range in a zone with the following settings:  
Color Change Hysteresis = .5° (applies as the temperature returns to the acceptable  
range)  
Occupied cooling setpoint = 76°  
Occupied heating setpoint = 70°  
Temp  
Occupied cooling setpoint: 76°  
75.5°  
.5° hysteresis  
70.5°  
.5° hysteresis  
Occupied heating setpoint: 70°  
Time  
Effective Setpoints  
The Effective Setpoints graph shows the current occupied or unoccupied setpoints. If occupied, these values are the current  
programmed setpoints plus the offset of any setpoint adjustment that may be in affect. If unoccupied, the values are the  
programmed unoccupied setpoints.  
64  
RTU Open  
Point Name/Description  
Default/Range  
Heating – (Occupied or Unoccupied, depending on mode) The current programmed Heating  
setpoint adjusted by any offset that may be in effect.  
R:  
R:  
0 to 120°F  
0 to 120°F  
Cooling – (Occupied or Unoccupied, depending on mode) The current programmed Cooling  
setpoint adjusted by any offset that may be in effect.  
Optimal Start – The earliest time, prior to occupancy, at which the Optimal Start function may  
begin to adjust the effective setpoints to achieve the occupied setpoints by the time scheduled  
occupancy begins. Enter 0 to disable Optimal Start.  
D:  
R:  
4 hr  
0 to 4 hr  
Occ Relative Humidity Setpoint – The percentage of relative humidity in the space during  
occupancy that will energize BO - 6 (Humidi-MiZer™).  
D:  
R:  
60%rh  
0 to Unoccupied  
RH Control  
Setpoint  
Unocc Relative Humidity Setpoint – The percentage of relative humidity in the space during the D:  
95%  
unoccupied time period that starts the unit and energizes BO - 6 (Humidi-MiZer™).  
R:  
30 to 100%  
650ppm  
DCV Max Ctrl Setpoint – The design difference between indoor and outdoor CO2 levels.  
D:  
R:  
0 to 9999 ppm  
50% Open  
20 to 90% Open  
Power Exhaust Setpoint - The outside air damper position at which the controller energizes the D:  
Power Exhaust relay. Configuration >Service Configuration > Economizer Exists must be set to  
Yes, and Configuration >Service Configuration > Continuous Occupied Exhaust must be set to  
R:  
No.  
Alarm Configuration  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Alarm Configuration  
HOME > CONFIG > ALARMS  
Point Name/Description  
Space Temperature Alarm  
Default/Range  
Occupied Alarm Hysteresis – This value is added to the occupied high effective  
setpoint and subtracted from the occupied low effective setpoint to establish the  
occupied high and low limits that the space temperature must exceed before an  
occupied SPT alarm is generated. The alarm returns to normal when the space  
temperature drops below the high effective setpoint or rises above the low effective  
setpoint.  
D:  
R:  
3°F  
0 to 20°F  
Alarm Delay (min/deg) – Determines the amount of delay before an occupied space  
temperature alarm is generated when the controller transitions to the occupied mode.  
The delay time equals this value multiplied by the difference between the sensor  
temperature and occupied alarm setpoint plus 15 minutes.  
D:  
R:  
10 minutes  
0 to 60 minutes  
Unoccupied Low SPT Alarm Limit –The value that the space temperature must drop  
below to generate a Space Temperature Alarm in the unoccupied mode. There is a  
fixed hysteresis of 1° F for return to normal.  
D:  
R:  
45°F  
-60 to 250°F  
RTU Open  
65  
Appendix A: RTU Open Points/Properties  
Point Name/Description  
Default/Range  
Unoccupied High SPT Alarm Limit – The value that the space temperature must  
exceed to generate a Space Temperature Alarm in the unoccupied mode. There is a  
fixed hysteresis of 1° F for return to normal.  
D:  
R:  
90°F  
-60 to 250°F  
Supply Air Temperature Alarm  
Low SAT Alarm Limit – The value that the supply air temperature must drop below to  
generate a Supply Air Temp Alarm. There is a fixed hysteresis of 1° F for return to  
normal.  
D:  
R:  
45°F  
-60 to 250°F  
High SAT Alarm Limit – The value that the supply air temperature must exceed to  
generate a Supply Air Temp Alarm. There is a fixed hysteresis of 1° F for return to  
normal.  
D:  
R:  
120°F  
-60 to 250°F  
Space Humidity Alarm  
Low Space Humidity Alarm Limit – The value that the relative humidity must drop  
below to generate a Low Space Humidity Alarm. Requires a space relative humidity  
transmitter and Configuration >Unit Configuration >Input 1 (or 2) Function set to  
Space RH Sensor.  
D:  
R:  
30%  
0 – 99 %  
High Space Humidity Alarm Limit – The value that the relative humidity must rise  
above to generate a High Space Humidity Alarm. Requires a space relative humidity  
transmitter and Configuration >Unit Configuration >Input 1 (or 2) Function set to  
Space RH Sensor.  
D:  
R:  
70%  
0 – 99 %  
IAQ/Ventilation Alarm  
D:  
R:  
1200ppm  
Occupied High CO2 Alarm Limit – The value that the CO2 sensor must exceed to  
generate an IAQ Alarm in the occupied mode. There is a fixed hysteresis of 100ppm  
for return to normal. Requires a space CO2 sensor and Configuration >Unit  
Configuration >Input 1 (or 2) Function set to IAQ Sensor.  
0 to 9999 ppm  
Service Configuration  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Configuration > Service Configuration  
HOME > CONFIG > SERVICE  
Point Name/Description  
Default/Range  
Unit Type – The type of equipment that the RTU Open is controlling.  
D:  
R:  
Heat/Cool  
Options:  
Heat/Cool  
Heat/Cool – Standard rooftop air handling unit.  
HP O/B Ctrl – Heat Pump application, uses reversing valve output to control heating  
and cooling.  
HP O/B Ctrl  
HP Y1/W1 Ctrl  
HP Y1/W1 Ctrl – Carrier Heat Pump application only.  
66  
RTU Open  
Point Name/Description  
Default/Range  
Compressor Stages – The number of mechanical cooling stages.  
D:  
R:  
One Stage  
One Stage  
Two Stages  
Economizer Exists – Set to Yes to enable economizer control for units equipped with  
an economizer damper.  
D:  
R:  
D:  
R:  
D:  
No  
No/Yes  
Electric  
Electric/Gas  
2
Heat Type – The type of heating that the unit has.  
Number Of Heat Stages – The number of heat stages.  
R: 1 /2 /0 (no heating)  
Continuous Occupied Exhaust – Configures the exhaust fan control strategy (BO-8). If D:  
Yes, the power exhaust runs continuously in occupied mode and is off in unoccupied  
mode. If No, the power exhaust is controlled by the Power Exhaust Setpoint.  
No  
R:  
No/Yes  
Indoor CO2 Sensor Value @min (ma) – The CO2 value that corresponds to a 4mA  
input at the appropriate input channel.  
D:  
R:  
D:  
R:  
D:  
R:  
0ppm  
0 to 9999 ppm  
2000 ppm  
0 to 9999 ppm  
0ppm  
Indoor CO2 Sensor Value @max (ma) – The CO2 value that corresponds to a 20mA  
input at the appropriate input channel.  
Outdoor CO2 Sensor Value @min (ma) – The CO2 value that corresponds to a 4 mA  
input at the appropriate input channel.  
0 to 9999 ppm  
2000 ppm  
0 to 9999 ppm  
-999.00 °F  
N/A  
Outdoor CO2 Sensor Value @max (ma) – The CO2 value that corresponds to a 20 mA D:  
input at the appropriate input channel.  
R:  
System Space Temperature – The network space temperature value that the  
controller is using for control (if applicable).  
D:  
R:  
System Cool Demand Level – The system cool demand level being received over the D:  
0.00  
network.  
R:  
0 - 3  
System Heat Demand Level – The system heat demand level being received over the D:  
0.00  
network.  
R:  
0 - 3  
System Outside Air Temperature – Allows the outside air temperature value to be  
network readable when enabled. Requires that controller is equipped with an outdoor  
air temperature sensor.  
D:  
R:  
-999.0°F  
N/A  
Service Test  
Service Test – Enable to stop automatic control so you can test the controller's  
outputs. Automatically resets to Disable after 1 hour.  
D:  
R:  
Disable  
Disable/Enable  
Disable  
Fan Test – Enable to test the controller's fan speeds. Sequences fan from low to high D:  
speed and operates at each speed for 1 minute. Resets to Disable when complete.  
Service Test must be set to Enable.  
R:  
Disable/Enable  
Compressor 1 Test – Enable to test the controller's compressor 1 output. Service  
Test must be set to Enable.  
D:  
R:  
Disable  
Disable/Enable  
RTU Open  
67  
Appendix A: RTU Open Points/Properties  
Point Name/Description  
Default/Range  
Compressor 2 Test – Enable to test the controller's compressor 2 output. Service  
Test must be set to Enable.  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
Disable  
Disable/Enable  
Disable  
Heat 1 Test – Enable to test the controller's heat 1 output. Service Test must be set  
to Enable.  
Disable/Enable  
Disable  
Heat 2 Test – Enable to test the controller's heat 2 output. Service Test must be set  
to Enable.  
Disable/Enable  
Disable  
Reversing Valve Test – Enable to test the controller's reversing valve output. Service  
Test must be set to Enable.  
Disable/Enable  
Disable  
Dehumidification Test – Enable to test the controller's humidimizer output. Service  
Test must be set to Enable.  
Disable/Enable  
Disable  
Power Exhaust Test – Enable to test the controller's exhaust fan output. Service Test D:  
must be set to Enable.  
R:  
Disable/Enable  
0% Open  
Economizer Test – Set to a value between 0 and 100% to test the controller's  
economizer output. Service Test must be set to Enable.  
D:  
R:  
D:  
R:  
0 to 100% Open  
0%  
Analog Output 2 Test – Analog Output 2 (0-10 Vdc) is currently unused.  
0 to 100%  
Maintenance  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Maintenance  
HOME > MAINT  
Point Name/Description  
Unit  
Default/Range  
Occupancy Status – The controller's occupancy status as determined by a network  
schedule, a local schedule, or a timed override.  
R:  
R:  
Occupied/Unoccupied  
Space Temp Sensor – The source of the controlling space temperature value.  
Sensor Failure  
SPT Sensor  
T55/T56  
Network  
Airside Linkage  
Locked Value  
Options:  
Sensor Failure – No valid space temperature or sensor status = failed.  
SPT Sensor – An SPT sensor is connected to the controller’s Rnet port.  
T55/56 – A T55, T56, or T59 sensor is connected to the controller’s J20 terminals.  
Network – A network temperature sensor is bound to the controller’s space temperature  
AV.  
Airside Linkage – The space temperature from a linked terminal.  
Locked Value –The controller’s space temperature input has been manually locked at a  
value.  
Safety Chain Feedback - Indicates a completed circuit from J1, 1 to J1, 9. This circuit is  
R:  
Off/Run Enabled  
typically used for safety devices that immediately stop unit operation when tripped.  
68  
RTU Open  
Point Name/Description  
Default/Range  
Fire Shutdown Shutdown indicates that a fire shutdown is in effect.  
R:  
R:  
Run Enabled/  
Shutdown  
Compressor Safety Status Trouble indicates that the compressor safety device has  
Normal/Trouble  
tripped.  
Enthalpy Status – The enthalpy status determined by an enthalpy switch.  
Humidistat Input Status – The humidity status determined by a humidistat.  
Reset Supply Fan Runtime Alarm – Set to Clear to reset Supply Fan Runtime to 0.  
R:  
R:  
High/Low  
High/Low  
D:  
R:  
D:  
R:  
D:  
R:  
D:  
R:  
Run  
Run/Clear  
Run  
Reset Comp 1 Runtime Alarm – Set to Clear to reset Compressor 1 Runtime to 0.  
Reset Comp 2 Runtime Alarm – Set to Clear to reset Compressor 2 Runtime to 0.  
Reset Filter Runtime Alarm – Set to On to reset Filter Runtime to 0.  
Run/Clear  
Run  
Run/Clear  
Off  
Off/On  
Occupancy  
BAS On/Off – Determines the occupancy state of the controller and can be set over the  
network by another device or third party BAS.  
D:  
R:  
Inactive  
Inactive  
Options:  
Occupied  
Unoccupied  
Inactive – Occupancy is determined by a configured schedule.  
Occupied – The controller is always in the occupied mode.  
Unoccupied – The controller is always in the unoccupied mode.  
Schedules – The controller's occupancy status based on the schedule.  
R:  
R:  
Occupied/Unoccupied  
Off/Active  
Pushbutton Override Active indicates if a user pushed the sensor's override button to  
override the occupancy state.  
Override Time Remaining – The amount of time remaining in an override period.  
R:  
0 to 240 minutes  
Runtime  
Supply Fan Runtime – The total number of hours that the supply fan relay has been  
energized since the runtime was last reset to 0 using Reset Supply Fan Runtime Alarm.  
R:  
R:  
___ hr  
___ hr  
Compressor 1 Runtime – The total number of hours that the Compressor 1 relay has  
been energized since the runtime was last reset 0 using Reset Comp 1 Runtime Alarm.  
Compressor 2 Runtime – The total number of hours that the Compressor 2 relay has  
been energized since the runtime was last reset using Reset Comp 2 Runtime Alarm.  
R:  
R:  
___ hr  
___ hr  
Filter Runtime – The total number of hours that the unit has been operating since the  
runtime was last reset to 0 using Reset Filter Runtime Alarm.  
RTU Open  
69  
Appendix A: RTU Open Points/Properties  
Alarms  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Alarms  
HOME > ALARM  
Point Name/Description  
Range  
Safety Chain – Indicates if the Safety Chain circuit trips.  
R:  
R:  
R:  
R:  
R:  
R:  
R:  
R:  
R:  
Normal/Alarm  
Fire Shutdown – Indicates if the Fire Shutdown circuit trips.  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
Compressor Safety – Indicates if the Compressor Safety circuit trips.  
Space Temp Sensor – Indicates if the space temperature sensor fails.  
Supply Air Temp Sensor – Indicates if the supply air temperature sensor fails.  
Outdoor Air Temp Sensor Alarm – Indicates if the outdoor air temperature sensor fails.  
Space Relative Humidity Sensor – Indicates if the space relative humidity sensor fails.  
IAQ Sensor – Indicates if the indoor air quality (CO2) sensor fails.  
OAQ Sensor – Indicates if the outdoor air quality (CO2) sensor fails.  
Space Temperature – Indicates if the space temperature sensor exceeds the high or low alarm R:  
limit.  
Alarming Temperature – The value of the alarming space temperature sensor.  
R:  
The sensor's  
range  
Alarm Limit Exceeded – The alarm limit that the alarming space temperature sensor exceeded. R:  
-60 to 250°F  
Normal/Alarm  
High Supply Air Temperature – Indicates if the supply air temperature exceeds the High SAT  
Alarm Limit.  
R:  
R:  
R:  
Low Supply Air Temperature – Indicates if the supply air temperature falls below the Low SAT  
Alarm Limit.  
Normal/Alarm  
Setpoint Slider – Indicates if the T56 sensor's setpoint slider potentiometer fails.  
Normal/Alarm  
Normal/Alarm  
Switch Configuration – Indicates if a duplicate configuration exists for two or more binary Input R:  
3, 5, 8, & 9 Functions.  
Analog Input Configuration – Indicates if a duplicate configuration exists at the analog Input 1  
& 2 Functions.  
R:  
R:  
R:  
Normal/Alarm  
Normal/Alarm  
Normal/Alarm  
High Space Relative Humidity – Indicates if the space relative humidity exceeds the High  
Space Humidity Alarm Limit.  
Low Space Relative Humidity – Indicates if the space relative humidity falls below the Low  
Space Humidity Alarm Limit.  
High CO2 – Indicates if the indoor CO2 level rises above the Occupied High CO2 Alarm Limit.  
R:  
R:  
Normal/Alarm  
Normal/Alarm  
Supply Fan Runtime – Indicates if the supply fan runtime exceeds the value of the Supply Fan  
Service Alarm Timer.  
Compressor 1 Runtime – Indicates if the compressor 1 runtime exceeds the value of the  
Compressor 1 Service Alarm Timer.  
R:  
Normal/Alarm  
70  
RTU Open  
Point Name/Description  
Range  
Compressor 2 Runtime – Indicates if the compressor 1 runtime exceeds the value of the  
Compressor 2 Service Alarm Timer.  
R:  
R:  
R:  
Normal/Alarm  
Filter – Indicates a dirty filter condition when the filter runtime exceeds the value of the Filter  
Service Alarm Timer or in response to a filter status switch binary input.  
Clean/Dirty  
Airside Linkage Alarm – Indicates if Linkage fails in a zoned system using Linkage.  
Normal/Alarm  
Linkage  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > Equipment > Linkage  
Properties > Equipment > Linkage  
Point Name/Description  
Range  
Linkage Collector – Allows access to the Collector's details.  
Airside Linkage Status – If Active, the controller is part of a linked system. If Not  
Active, the controller is a stand-alone device.  
R:  
Active/Not Active  
If Airside Linkage Status is Active, the following provide information received from  
the VVT Master (as applicable):  
Occupancy Status  
Space Temperature  
Occupied Cooling Setpoint  
Occupied Heating Setpoint  
Unoccupied Cooling Setpoint  
Unoccupied Heating Setpoint  
Indoor Air CO2  
Space Relative Humidity  
I/O Points  
The values shown on the I/O Points Properties page are the raw values at the I/O objects and may not match  
values shown on status displays that are affected by control program logic.  
i-Vu users logged in as Power User and above are able to edit various parameters associated with the input  
channels and the display names for all channels.  
We strongly recommend that you leave these parameters at their defaults. The RTU Open is not a  
programmable controller. I/O can only be used for the purpose designed in the equipment control program.  
Modifying these parameters may result in unpredictable equipment control.  
See Wiring inputs and outputs (page 12) for more information. This table lists each of the I/O Channels, their  
functions, associated hardware, and terminal numbers.  
RTU Open  
71  
Appendix A: RTU Open Points/Properties  
i-Vu / Field Assistant:  
BACview:  
Navigation:  
Properties > I/O Points  
N/A  
Point Name/Description  
Space Temp – The value of the Optional SPT (Rnet) sensor. Also allows i-Vu & Field Assistant users access to sensor  
configuration. See Carrier Sensors Installation Guide for additional details.  
input 1 – Input Channel 1; 4 - 20 mA only. User-configurable for IAQ, OAQ, or Space RH.  
input 2 – Input Channel 2; 4 - 20 mA only. User-configurable for IAQ, OAQ, or Space Relative Humidity.  
input 6 – Input Channel 6; 10K Thermistor only. Supply Air Temperature.  
input 7 – Input Channel 7; 10K Thermistor only. Outside Air Temperature.  
input 10 – Input Channel 10; 10K Thermistor only. Space Temperature (T55, 56, 59).  
input 11 – Input Channel 11; 100K Potentiometer only. Setpoint adjust (T56, 59).  
slidepot voltage reading – Input Channel 11; used to detect an open circuit (faulty Setpoint adjustment mechanism).  
input 3 – Input Channel 3; Dry Contact only. User-configurable for No Function, Compressor Safety, Fan Status, Filter  
Status, Remote Occupancy, or Door Contact.  
input 4 – Input Channel 4; Dry Contact only. Safety Chain.  
input 5 – Input Channel 5; Dry Contact only. User-configurable for No Function, Fire Shutdown, Fan Status, Filter  
Status, Remote Occupancy, or Door Contact.  
input 8 – Input Channel 8; Dry Contact only. User-configurable for No Function, Enthalpy, Fan Status, Filter Status,  
Remote Occupancy, or Door Contact.  
input 9 – Input Channel 9; Dry Contact only. User-configurable for No Function, Humidistat, Fan Status, Filter Status,  
Remote Occupancy, or Door Contact.  
Sensor Invalid – Reflects the status of the Space Temp (Rnet) input. On = Space Temp invalid,  
Off = Space Temp valid.  
ao 1 – Analog Output Channel 1; jumper selectable.  
ao 2 – Analog Output Channel 2; 0 - 10 Vdc. Not Utilized.  
relay 1 – Binary Output 1; Fan (G) Output.  
relay 2 – Binary Output 2; Heat 2 (W2) Output.  
relay 3 – Binary Output 3; Heat 1 (W1) Output.  
relay 4 – Binary Output 4; Cool 2 (Y2) Output.  
relay 5 – Binary Output 5; Cool 1 (Y1) Output.  
relay 6 – Binary Output 6; Humidi-MiZer ™ Output.  
relay 7 – Binary Output 7; Reversing Valve Output.  
relay 8 – Binary Output 8; Power Exhaust Output.  
72  
RTU Open  
Appendix B: Single Point Linkage and Device Address Binding  
Single Point Linkage  
The RTU Open receives data from other Open controllers when they are installed as part of an Open system.  
The data transfer may take the form of Single Point Linkage (SPL), which is automatic, or Device Address  
Binding, which you must configure.  
Currently, the RTU Open implements Single Point Linkage for 3 variables: Refer to configuration section -  
complete list - make list to system system configuration1.....might be different for RTU - might be unit config  
System Cool Demand Level  
System Heat Demand Level  
System Outside Air Temperature  
Network Points for which SPL has been implemented are displayed in i-Vu and Field Assistant on the  
Properties page > Network Points tab.  
The following example involves outside air temperature. System Heat & Cool Demand Level behaves  
similarly, except that their usage involves a specific application loaded on a Universal Controller Open. See UC  
Open Installation Guide for additional information. In either case, note that the BACnet type and instance  
numbers specified in the Address field of these variables have been predefined.  
Network variables for which SPL is used are easily identified on the Properties page > Network Points tab.  
The asterisk in the BACnet address invokes the SPL function. These addresses cause the controller to issue a  
BACnet “who has” command for this variable. The controller binds to the closest of the first five devices from  
which it receives a valid response.  
RTU Open  
73  
 
Appendix B: Single Point Linkage and Device Address Binding  
Device Address Binding  
As described previously, Device Address Binding allows the RTU Open to receive data from other Open  
controllers when they are connected by a network. You must configure this method.  
Currently, the RTU Open allows Device Address Binding (DAB) only for System Space Temperature.  
Network Points on which DAB may be implemented are displayed in i-Vu and Field Assistant on the Properties  
page > Network Points tab with an undefined BACnet address.  
74  
RTU Open  
Index  
Index  
DCV Max Vent Damper Pos • 59  
Dehumidification Test • 66  
Economizer Exists • 40, 66  
Economizer High OAT Lockout • 59  
Economizer Output • 58  
Economizer Test • 66  
B
BACnet compliance • 57  
BACnet port • 11  
BT485 • 10  
Enthalpy Status • 68  
Fan Mode • 37, 59  
C
Fan Off Delay • 59  
Fan Test • 66  
Compliance • 57  
D
Filter Alarm • 70  
Filter Runtime • 68  
Filter Service Alarm Timer • 59  
Fire Shutdown • 68  
Fire Shutdown alarm • 70  
Heat 1 Test • 66  
Duct Air Temperature sensor • 22  
Duct sensors  
Duct Air Temperature sensor • 22  
Supply Air Temperature sensor • 21  
Heat 2 Test • 66  
Heat Type • 40, 66  
F
Heating Capacity • 61  
FCC compliance • 57  
Field Assistant • 58  
Heating Design Temp • 61  
Heating Lockout Temperature • 59  
High CO2 alarm • 70  
I
High SAT Alarm Limit • 65  
High Space Humidity Alarm Limit • 65  
High Space Relative Humidity alarm • 70  
High Supply Air Temperature alarm • 70  
HP Rev Cycle Lockout Temmp • 59  
Humidistat Input Status • 68  
Hysteresis • 61  
IAQ Sensor alarm • 70  
Indoor Air CO2 • 58, 71  
Indoor CO2 Sensor Value @max (ma) • 40, 66  
Indoor CO2 Sensor Value @min (ma) • 40, 66  
Input # Function • 37, 59  
i-Vu • 58  
L
Linkage • 73  
M
Module Status report • 55  
MS/TP network, wiring • 10  
P
Input # Switch Configuration • 37, 59  
LAT Airflow Increase • 58  
Linkage Collector • 71  
Points/Properties • 58  
Airside Linkage Alarm • 70  
Airside Linkage Status • 71  
Alarm Delay (min/deg) • 65  
Alarm Limit Exceeded • 70  
Alarming Temperature • 70  
Analog Input Configuration • 70  
Analog Output 2 Test • 65  
Low SAT Alarm Limit • 65  
Low Space Humidity Alarm Limit • 65  
Low Space Relative Humidity alarm • 70  
Low Supply Air Temperature alarm • 70  
Maximum Heating SAT • 59  
Minimum Cooling SAT • 59  
Number of Heat Stages • 40, 66  
OAQ Sensor alarm • 70  
OAT System Sensor • 66  
Occ Relative Humidity Setpoint • 39, 61  
Occupancy Source • 37, 59  
Occupancy Status • 68, 71  
Occupied Alarm Hysteresis • 65  
Occupied Cooling • 39, 61  
Occupied Cooling 1 • 61  
Occupied Cooling 2 • 61  
Occupied Cooling Setpoint • 71  
Occupied Heating • 39, 61  
Occupied Heating 1 • 61  
Occupied Heating 2 • 61  
Occupied Heating Setpoint • 71  
Occupied High CO2 Alarm Limit • 65  
BAS On/Off • 68  
Compressor 1 Runtime • 68  
Compressor 1 Runtime alarm • 70  
Compressor 1 Service Alarm Timer • 59  
Compressor 1 Test • 66  
Compressor 2 Runtime • 68  
Compressor 2 Runtime alarm • 70  
Compressor 2 Service Alarm Timer • 59  
Compressor 2 Test • 66  
Compressor Safety alarm • 70  
Compressor Safety Status • 68  
Compressor Stages • 40, 66  
Continuous Occupied Exhaust • 40, 66  
Cooling Capacity • 61  
Cooling Design Temp • 61  
Cooling Lockout Temp • 59  
DCV Max Ctrl Setpoint • 39, 59  
RTU Open  
75  
Index  
Operating Mode • 58  
Rnet wiring specifications • 20  
Optimal Start • 39, 61  
Outdoor Air CO2 • 58  
S
Outdoor Air Temp Sensor Alarm • 70  
Outdoor Air Temperature • 58  
Outdoor CO2 Sensor Value @max (ma) • 40, 66  
Outdoor CO2 Sensor Value @min (ma) • 40, 66  
Outside Air Temp Calibration • 59  
Override Time Remaining • 68  
Power Exhaust Setpoint • 39, 61  
Power Exhaust Test • 66  
Pushbutton Override • 59, 68  
Reset Comp 1 Runtime Alarm • 68  
Reset Comp 2 Runtime Alarm • 68  
Reset Filter Runtime Alarm • 68  
Reset Supply Fan Runtime Alarm • 68  
Reversing Valve Test • 66  
Serial number • 55  
SPT sensors • 20  
Supply Air Temperature sensor • 21  
T
temperature sensors  
Duct Air Temperature sensor • 22  
SPT sensors • 20  
Supply Air Temperature sensor • 21  
Troubleshooting • 55  
W
Wiring specifications  
Network • 11  
Rnet • 20  
Safety Chain alarm • 70  
Safety Chain Feedback • 68  
Schedules • 68  
Service Test • 66  
Setpoint Slider • 70  
Space Relative Humidity • 58, 71  
Space Relative Humidity Sensor alarm • 70  
Space sensor type • 37, 59  
Space Temp Calibration • 59  
Space Temp Sensor • 70  
Space Temp Sensor Alarm • 70  
Space Temperature • 71  
Space Temperature - Prime Variable • 58  
Space Temperature Alarm • 70  
Supply Air Temp Calibration • 59  
Supply Air Temp Sensor alarm • 70  
Supply Air Temperature • 58  
Supply Fan Runtime • 68  
Supply Fan Runtime alarm • 70  
Supply Fan Service Alarm Timer • 59  
Supply Fan Status • 58  
Switch Configuration • 70  
System Cool Demand Level • 66  
System Heat Demand Level • 66  
System Mode • 58  
System Outside Air Temperature • 66  
System Space Temperature • 66  
T5x Override Duration • 59  
Unit Start Delay • 59  
Unit Type • 40, 66  
Unocc Free Cool Enable • 59  
Unocc Relative Humidity Setpoint • 39, 61  
Unoccupied Cooling • 39, 61  
Unoccupied Cooling 1 • 61  
Unoccupied Cooling 2 • 61  
Unoccupied Cooling Setpoint • 71  
Unoccupied Heating • 39, 61  
Unoccupied Heating 1 • 61  
Unoccupied Heating 2 • 61  
Unoccupied Heating Setpoint • 71  
Unoccupied High SPT Alarm Limit • 65  
Unoccupied Low SPT Alarm Limit • 65  
Vent Dmpr Pos / DCV Min Pos • 59  
R
Rnet • 20  
76  
RTU Open  
CARRIER CORPORATION ©2010  
A member of the United Technologies Corporation family · Stock symbol UTX · Catalog No. 11-808-427-01 · 11/19/2010  

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