Carrier 48/50HC04-28 User guide

48/50TC04---30, 50TCQ04---24
48/50HC04---28, 50HCQ04---12
48/50LC04---26
Factory Installed Option
RTU Open
Multi---Protocol Controller
Controls, Start---Up, Operation
and Troubleshooting
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 2.........................
GENERAL 2.........................................
SENSOR/ACCESSORY INSTALLATION 2................
Sensors and Accessories 4.............................
User Interfaces 4.....................................
Install Analog Sensors 4...............................
Supply Air Sensor (SAT) 4...........................
Outdoor Air Sensor (OAT) 4..........................
Space Temperature Sensor (SPT) 4.....................
Sensor Averaging 9...............................
CO2Sensor(s) (IAQ and OAQ) 9......................
Relative Humidity Sensors (Space or Duct Mounted) 11.....
Installing Discrete Inputs 11............................
Compressor Safety 11...............................
Humidistat 11.....................................
Single Enthalpy (Outdoor Enthalpy) 11.................
Differential Enthalpy 11.............................
Fire Shutdown 12..................................
Filter Status 12.....................................
Fan Status 12......................................
Remote Occupancy 12...............................
IGC Override 12...................................
Communication Wiring--Protocols 13.....................
General 13........................................
i--VuRBuilding Automation System 13.................
BACnetRMS/TP 13................................
Modbus 14.......................................
Johnson N2 14.....................................
LonWorks 14......................................
Local Access 15....................................
START--UP 16........................................
Additional Installation/Inspection 16.....................
Power Exhaust Relay Power 16........................
Service Test 16......................................
Fan Test 16.......................................
High Speed Fan Test 16..............................
Compressor 1 and Compressor 2 Test 16.................
Heat 1 and Heat 2 Test 16............................
Dehumidification Test 16.............................
Power Exhaust Test 17..............................
Economizer Test 17.................................
VFD Speed Test 17.................................
Configuration 17....................................
Setpoint 17.......................................
Unit 17..........................................
Inputs 18.........................................
Service Configuration 19.............................
OPERATION 20......................................
Occupancy 20.......................................
Indoor (Supply) Fan 21...............................
Cooling 21.........................................
Supply Fan 22......................................
Economizer 22......................................
Enthalpy Control 22..................................
Space Air Quality 23.................................
Power Exhaust 23....................................
Pre--Occupancy Purge 23..............................
Heating 23.........................................
Indoor Air Quality 23.................................
Dehumidification 24..................................
Demand Limit 24....................................
Unoccupied Free Cooling 24...........................
Optimal Start 24.....................................
Fire Shutdown 24....................................
Compressor Safety 24.................................
Fan Status 25.......................................
Filter Status 25......................................
Door Switch 25......................................
Remote Occupancy 25................................
Linkage 25.........................................
TROUBLESHOOTING 25..............................
General 25.........................................
Replacing the RTU Open’s Battery 25...................
Thermistor Troubleshooting 26.........................
Software Version 26..................................
Communication LED’s 26.............................
Alarms 29..........................................
Performance 31......................................

2
Third Party Networking 32.............................
APPENDIX A -- USER INTERFACE MENUS 33............
APPENDIX B -- THIRD PARTY POINTS LIST 41..........
APPENDIX C -- EQUIPMENT TOUCH
NAVIGATION SCREENS 45..............
RTUOPENSTART--UPSHEET 49.......................
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical
components. Only trained and qualified service personnel
should install, repair, or service air-conditioning
equipment. Untrained personnel can perform the basic
maintenance functions of replacing filters. Trained service
personnel should perform all other operations.
When working on air-conditioning equipment, observe
precautions in the literature, tags and labels attached to
the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Have fire extinguisher available. Read these
instructions thoroughly and follow all warnings or
cautions attached to the unit. Consult local building codes
and National Electrical Code (NEC) for special
requirements.
Recognize safety information. This is the safety--alert
symbol . When you see this symbol on the unit and in
instructions or manuals, be alert to the potential for
personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION. These words are used with the safety--alert
symbol. DANGER identifies the most serious hazards
which will result in severe personal injury or death.
WARNING signifies a hazard which could result in
personal injury or death. CAUTION is used to identify
unsafe practices which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect all power to the unit before performing
maintenance or service. Unit may automatically start
if power is connected.
!WARNING
GENERAL
The RTU Open controller is an integrated component of
the Carrier rooftop unit. Its internal application
programming provides optimum performance and energy
efficiency. RTU Open enables the unit to run in 100%
stand--alone control mode, Carrier’s i--VuROpen network,
or a Third Party Building Automation System (BAS).
On--board DIP switches allow you to select your protocol
(and baud rate) of choice among the four most popular
protocols in use today: BACnetR, Modbus, Johnson N2
and LonWorks. (See Fig. 1.)
NOTE: Lon Works requires addition of LonWorks
Option card.
Carrier’s diagnostic display tools such as Equipment
Touch or Field Assistant can be used with the RTU Open
controller. Access is available via a 5--pin J12 access port
or Rnet communication network.
SENSOR/ACCESSORY
INSTALLATION
There are a variety of sensors and accessories available
for the RTU Open. Some of these can be factory or field
installed, while others are only field installable. The RTU
Open controller may also require connection to a building
network system or building zoning system. All field
control wiring that connects to the RTU Open must be
routed through the raceway built into the corner post of
the unit or secured to the unit control box with electrical
conduit. The unit raceway provides the UL required
clearance between high and low-voltage wiring. Pass the
control wires through the hole provided in the corner post,
then feed the wires thorough the raceway to the RTU
Open. Connect the wires to the removable Phoenix
connectors and then reconnect the connectors to the board.
See Fig. 1 and Table 1 for board connections and Fig. 2
Through Fig. 5 for Typical Factory RTU Open wiring.
IMPORTANT: Refer to the specific sensor or accessory
instructions for its proper installation and for rooftop unit
installation refer to base unit installation instructions and
the unit’s wiring diagrams.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, death and/or equipment damage.
Disconnect electrical power and use lock--out tags
before wiring the RTU Open controller.
!WARNING
48---50LHTCQ---01T

3
J4
J2J1
J5 J5
J22
J17
J19 J14
J11
J22
J3
J13
J12
J15
J20
Network Comm
Configurable - Input_8
24 VAC
Configurable - Input_5
24 VAC
Configurable - Input_3
24 VAC
Input_9 (Humidistat)
24 VAC
24 VAC
Input _8 (Enthalpy)
AO-1 (ECON)
Gnd
(OAT)
Gnd
(SAT)
Input_5 (SMK) Input_4 (R) BO-5 (Y1) BO-4 (Y2) BO-3 (W1) BO-2 (W2) BO-1 (G) Gnd Input_3 (X) 24 VAC IN
+24 VDC
Input_2 (CO2/RH)
Gnd
+24 VDC
Input_1 (CO2/RH)
Gnd
Board Power
(AO-1)
0-10VDC
4-20mA
BO-6
(H) Humidimizer
BO-7
(Reversing Valve/High Speed Fan/Y3)
BO-8
(Power Exhaust)
LonWorks
Option Card
Port
Example set for
BACnet MS/TP
and 76.8K baud
(1, 2, and 4 ON)
Recommended for all
i-Vu Open installations
Protocol Selector SPT (temp input) BACnet, Modbus, or N2
(LON connection J15)
SPT (common)
SPT (offset input)
*Remove
both for 0-5V
AO-2
GND
(2-10V)
3-Volt
Lithium
Battery
BO-1 BO-2 BO-3 BO-4 BO-5
BO-6
BO-7
BO-8
VFD Output
C14129
Fig. 1 -- RTU Open Control Module
48---50LHTCQ---01T

4
Table 1 – RTU Open Inputs and Outputs
POINT NAME BACnet OBJECT
NAME TYPE OF I/O CONNECTION PIN NUMBER(S) CHANNEL DESIGNATION
DEDICATED INPUTS
Space Temp / Zone Temp zone_temp AI (10K Thermistor) J 2 0 --- 1 & 2 Analog Input 10
Supply Air Temperature sa_temp AI (10K Thermistor) J 2 --- 1 & 2 Analog Input 6
Outside Air Temperature oa_temp AI (10K Thermistor) J 2 --- 3 & 4 Analog Input 7
Space Temperature Offset Pot stpt_adj_offset AI (100K Potentiometer) J 2 0 --- 3 & 4 Analog Input 11
Safety Chain Feedback safety_status BI (24 VAC) J 1 --- 9 Binary Input 4
Compressor Safety Status (1) comp_status BI (24 VAC) J 1 --- 2 Binary Input 3
Fire Shutdown Status firedown_status BI (24 VAC) J 1 --- 1 0 Binary Input 5
Enthalpy Status enthalpy_status BI (24 VAC) J 2 --- 6 & 7 Binary Input 8
Humidistat Input Status humstat_status BI (24 VAC) J 5 --- 7 & 8 Binary Input 9
Zone Temperature n/a n/a J 1 3 --- 1 --- 4 Rnet
CONFIGURABLE INPUTS (4)
Indoor Air CO2 iaq A I ( 4 --- 2 0 m A )
J 4 --- 2 & 3 o r J 4 --- 5 & 6
Analog Input 2
Outdoor Air CO2 oaq A I ( 4 --- 2 0 m A ) Analog Input 1
Space Relative Humidity space_rh A I ( 4 --- 2 0 m A ) Analog Input 10
Supply Fan Status (2) sfan_status BI (24 VAC)
J 5 --- 1 & 2 o r J 5 --- 3 & 4,
J 5 --- 5 & 6 o r J 5 --- 7 & 8 (3)
BinaryInput3,5,8,or9,exceptwhereintrinsicinputisused
Filter Status (2) filter_status BI (24 VAC) BinaryInput3,5,8,or9,exceptwhereintrinsicinputisused
Door Contact (2) door_contact_status BI (24 VAC) BinaryInput3,5,8,or9,exceptwhereintrinsicinputisused
Remote Occupancy input (2) occ_contact_status BI (24 VAC) BinaryInput3,5,8,or9,exceptwhereintrinsicinputisused
IGC input (2) igcovr_status BI (24 VAC) Binary Input 9. Mandatory input on gas heat units.
OUTPUTS
Economizer Output econ_output AO (4 --- 20mA) J 2 --- 5 Analog Output 1
Supply Fan VFD vfd_output A O ( 2 --- 1 0 V d c) J 2 2 --- 1 & 2 Analog Output 2
Supply Fan Relay sfan BO Relay (24VAC, 1A) J 1 --- 4 Binary Output 1 (G)
Cool 1 Relay State comp_1 BO Relay (24VAC, 1A) J 1 --- 8 Binary Output 5 (Y1)
Cool 2 Relay State comp_2 BO Relay (24VAC, 1A) J 1 --- 7 Binary Output 4 (Y2)
Cool 3 Relay State comp_3 BO Relay (24VAC, 1A) J 1 1 --- 5 & 6 Binary Output 7 (Y3)
Heat 1 Relay State heat_1 BO Relay (24VAC, 1A) J 1 --- 6 Binary Output 3 (W1)
Heat 2 Relay State heat_2 BO Relay (24VAC, 1A) J 1 --- 5 Binary Output 2 (W2)
Power Exhaust Relay State pexh BO Relay (24VAC, 1A) J11---2&3(N.O.) Binary Output 8 (PE)
Dehumidification Relay dehum BO Relay (24VAC, 1A) J11---7&8(N.O.) Binary Output 6
(1) Safety Chain Feedback: 24Vac required at this terminal to provide “Run Enable” status. See Input/Output section for additional instructions.
(2) These inputs are configurable. If installed, they take the place of the default input on the specific channel. See appropriate Input Configuration Section for wiring and setup instructions.
(3) Pa r a l l e l p i n s J 5 --- 1 = J 2 --- 6 , J 5 --- 3 = J 1 --- 1 0 , J 5 --- 5 = J 1 --- 2 a r e u s e d f o r f i l e d i n s t a l l a t i o n .
(4) Refer to the input configuration and accessory sections for more detail.
Sensors and Accessories
The RTU Open controller is configurable with the
following field-supplied sensors:
NOTE: Supply air temperature sensor (33ZCSENSAT) is
factory-installed.
SSpace temperature sensor (ZS--CAR, ZS--C--CAR,
ZS--H--CAR, ZS--HC--CAR, ZSPL--C--CAR,
ZSPL--H--CAR, ZSPL--HC--CAR, ZSP--CAR,
ZSP--C--CAR, ZSP--H--CAR, ZSP--HC--CAR ,
33ZCT55SPT, 33ZCT56SPT, or 33ZCT59SPT)
SIndoor air quality sensor (ZS--C--CAR, ZS--HC--CAR,
Z S P L -- C -- C A R , Z S P L -- H C -- C A R , Z S P -- C -- C A R ,
ZSP--HC--CAR, 33ZCSPTCO2--01,
33ZCSPTCO2LCD--01, 33ZCT55CO2--02, or
33ZCT56CO2--02) required for demand control
ventilation.
SOutdoor air quality sensor (33ZCSPTCO2--01,
33ZCSPTCO2LCD--01)
SCO2aspirator box (C33ZCCASPCO2) required for CO2
return duct/outside air applications
SOutdoor air enthalpy switch (33CSENTHSW)
SReturn air enthalpy sensor (33CSENTSEN) required for
differential enthalpy control
SSpace relative humidity sensor (33ZCSENSRH-02)
SDuct relative humidity (33ZCSENDRH-02)
SHumidistat (--HL--38MG-029) (not permitted for use on
48LC 07--26 units due to same input as IGC input)
SSmoke Detectors (CRSMKSEN002A00,
CRSMKKIT002A00)
SFan and/or Filter Status (CRSTATUS001A00,
CRSTATUS005A00)
User Interfaces
SField Assistant (USB-TKIT required)
SWall mounted Equipment Touch
SWall mounted System Touch
Install Analog Sensors
Supply Air Sensor (SAT)
The factory supplies the discharge (supply) air sensor with
the unit and is pre--wired.
Unit/Size SAT Shipping Location/Installation Location
LC 04 --- 12
HC/TC 04--- 16
HCQ 04--- 12
T C Q 0 4 --- 1 4
The SAT is secured to the unit’s supply duct opening.
This sensor must be relocated into the supply duct
during unit installation.
LC 14 --- 26
HC 17 --- 24
TC/TCQ 17--- 30
The SAT is mounted through the side of the heat
chamber below the fan deck, and does NOT require
relocation.
OutdoorAirSensor(OAT)
The OAT is supplied with the economizer option or
accessory. It is wired through the 12-pin plug (PL6) in the
return air section of the unit and is mounted on the
economizer assembly.
Space Temperature Sensor (SPT)
There are 2 types of space temperature sensors available
from Carrier, resistive input non-communicating (T55, T56,
and T59) and Rnet communicating (ZS--CAR, ZS--C--CAR,
ZS--H--CAR, ZS--HC--CAR, ZSPL--C--CAR, ZSPL--H--CAR,
Z S P L -- H C -- C A R , Z S P -- C A R , Z S P -- C -- C A R , Z S P -- H -- C A R ,
ZSP--HC--CAR) sensors. Each type has a variety of options
consisting of: timed override button, set point adjustment, a
LCD screen, combination of humidity or CO2sensing and
communication tie in. Space temperature can be also be
written to from a building network or zoning system.
However, it is still recommended that return air duct sensor
be installed to allow stand-alone operation for back-up.
Refer to the configuration section for details on controller
configurations associated with space sensors.
48---50LHTCQ---01T

5
C14119
Fig. 2 -- Typical Factory Option Wiring -- 50LC 14--26 Shown
48---50LHTCQ---01T

6
C14146
Fig. 3 -- Typical Factory Option Wiring -- 48LC 04--06 Shown
48---50LHTCQ---01T

7
C13768
Fig. 4 -- Typical Factory Option Wiring -- 48TC 17--30 Shown
48---50LHTCQ---01T

8
C13668
Fig. 5 -- Typical Factory Option Wiring -- 50HC 17--28 Shown
48---50LHTCQ---01T

9
Resistive Non--Communicating Sensor Wiring
For sensor with setpoint adjustment up to 1000 ft (305m),
use three-conductor shielded cable 20 gauge wire to
connect the sensor to the controller. For non set point
adjustment (slidebar) or return air duct sensor, an
unshielded, 18 or 20 gauge, two-conductor, twisted pair
cable may be used. Below is the list of the connections of
the SPT to the RTU Open, refer to Fig. 6 and 7 for typical
connections at the sensor.
SJ20-1 = temperature sensor input (SEN)
SJ20-2 = sensor common
SJ20-3 = Setpoint adjustment input (SET)
NOTE: See Fig. 8 for space temperature sensor averaging.
T55/56 Override button will no longer function when sensors
are averaged. Only Sensor 1 T56 STO input can be used.
2345 61
SW1
SEN SET
Cool Warm
BRN (GND)
BLU (SPT) SENSOR WIRING
JUMPER
TERMINALS
AS SHOWN
BLK
(T56)
C07131
Fig. 6 -- Space Temperature Sensor
Typical Wiring (33ZCT56SPT)
OR SET SEN
OPB COM- PWR+
BLU (SPT)
BLK (STO)
24 VAC
SENSOR
WIRING
POWER
WIRING
BRN (COM)
NOTE: Must use a separate isolated transformer.
J20-3
J20-2
J20-1
C10291
Fig. 7 -- Space Temperature Sensor
Typical Wiring (33ZCT59SPT)
Rnet Communicating Sensor Wiring
The Rnet bus allows local communication with the RTU
Open, including communicating sensors. The Rnet bus
can hold up to 6 devices in the following combinations
wired in daisy-chain or hybrid configuration:
S1-4 ZS--CAR sensor(s)
S1 ZSPL--CAR or ZSP--CAR sensor
S1-4 SPS sensor(s), and 1ZSPL--CAR or ZSP--CAR sensor
SAny of the above combinations, plus CO2or RH
combination
NOTE: Additional ZS sensors must be addressed. Use
the jumpers on the ZS sensor’s circuit board and refer to
the sensor installation instructions for addressing.
For Rnet wiring up to 500ft (152m), use 18 AWG 4
conductor unshielded plenum rated cable. The RTU Open’s
J13-RNET connection has a 4 pin Phoenix connector wired
as described below, Fig. 9 shows sensor Rnet wiring.
SRNET -- 1 = Signal ground (GND)
SRNET -- 2 = Signal (Rnet+)
SRNET -- 3 = Signal (Rnet--)
SRNET -- 4 = Power (+12v)
Sensor Averaging
Non--communicating sensors:
See Fig. 8 for space temperature sensor averaging
configurations, only combinations of 4 or 9 sensors will
operate correctly.
NOTE: T55/T56 Override button will no longer function
when sensors are averaged. Only 1 T56 STO input can be
used. Non--communication CO2sensors can not be
averaged.
Communicating sensors:
Any combination of sensors described in the “Rnet
Communicating Sensor Wiring” section can be used.
NOTE: Communicating CO2sensors and RH sensors can
be averaged if within the realm described.
CO2 Sensor(s) (IAQ and OAQ)
The indoor air quality (IAQ) and outdoor air quality
(OAQ) sensors monitor carbon dioxide (CO2) levels. This
information is used to monitor the quality of air in terms
of parts per million (PPM). The same sensor is used for
inside, outside, and duct monitoring, except an aspirator
box is required for outside and duct mounting. The CO2
sensor is preset for a range of 0 to 2000 ppm and a linear
mA output of 4 to 20. The rooftop unit may have a factory
installed CO2sensor on the side of the economizer
assembly in the return air section of the unit and is
pre-wired and pre-configured at the factory. For field
installed sensors, a field supplied transformer must be
used to power the sensor. Refer to the instructions
supplied with the CO2sensor for electrical requirements
and terminal locations. RTU Open configurations must be
changed after adding a CO2sensor. See below and Fig. 10
for typical CO2sensor wiring.
SJ4--2 or J4--5 = 4--20mA signal input
SJ4--3 or J4--6 = signal common
NOTE: The factory used J4-2&3 for CO2(IAQ) sensor
inputs.
48---50LHTCQ---01T

10
Combination Temperature and CO2Sensor
If using a combination temperature and CO2sensor
(33ZCT55CO2--02 or 33ZCT56CO2--02), refer to the
installation instructions provided with the sensor.
LEGEND
RED RED
BLK BLK
J20
1
2
RED
BLK BLK
RED
BLK
RED
SENSOR 2 SENSOR 3 SENSOR 4SENSOR 1
SPACE TEMPERATURE AVERAGING — 4 SENSOR NON-COMMUNICATING APPLICATION
J20
RED
BLK
RED
BLK
SENSOR 2
SENSOR 1
RED
RED
BLK
SENSOR 3
SENSOR 4
BLK
BLK
RED
RED RED
BLK BLK
SENSOR 8 SENSOR 9
SENSOR 5
RED
BLK
SENSOR 6
SENSOR 7
BLK
RED
SPACE TEMPERATURE AVERAGING — 9 SENSOR NON-COMMUNICATING APPLICATION
Factory Wiring
Field Wiring
1
2
C14130
Fig. 8 -- Space Temperature Averaging for Non--Communicating Sensors
C10820
Fig. 9 -- Typical Rnet Communication Sensor Wiring
To controller
24 Vac Line
Dedicated Transforme
r
+
-
24 Vac
or Vdc
8 7 6 5 4
2 1
SENSOR LEGEND
1 +24 Vac/Vdc
2 Gnd (-24 Vac/Vdc)
4 -Thermistor
5 +Thermistor
6 4-20 mA
7 SIG COM
8 0-5 Vdc
C12748
Fig. 10 -- Indoor/Outdoor Air Quality (CO2)Sensor
(33ZCSPTCO2--01 or 33ZCSPTCO2LCD--01)
Typical Wiring Diagram
48---50LHTCQ---01T

11
Relative Humidity Sensors (Space or Duct
Mounted)
The accessory space humidity sensor or duct humidity
sensor is used to measure the relative humidity of the air
within the space or return air duct. The RH reading is used
to control the Humidi-MiZerRoption of the rooftop unit. For
wiring distances up to 500 ft (152m), use a 3-conductor, 18
or 20 AWG shielded cable. The shield must be removed
from the sensor end of the cable and grounded at the unit
end. The current loop power for the sensor is provided by
the RTU Open controller as 24vdc. Refer to the instructions
supplied with the RH sensor for electrical requirements and
terminal locations. RTU Open configurations must be
changed after adding a RH sensor. See below and Figs. 11 &
12 for typical non--communicating RH sensor wiring.
SJ4--1 or J4--4 = 24vdc loop power
SJ4--2 or J4--5 = 4--20mA signal input
NOTE: The factory default for dehumidification control
is a normally open humidistat.
Installing Discrete Inputs
Compressor Safety
The compressor safety input provides the RTU Open with
feedback to when the compressor is not running and
should be. This feedback can be provided by a
Compressor Lock-Out (CLO) device or current switch
when field installed. Compressor safety is a dedicated
input on the configurable input 3 and tells the RTU Open
when the compressor is locked out. The normal condition
for compressor safety is good operation. A normally open
compressor safety is the factory default for all units.
Follow specific accessory instructions if installing a CLO
device. The CLO should wire into the unit’s Integrated
Staging Control (ISC) board (48/50LC 07--26) or Central
Terminal Board (CTB) (all 48/50TC(Q), 48/50HC(Q), and
04--06 48/50LC units).
NOTE: Input 3 can also be wired into J--5.
SW2
12345 6
ON
Io Vin Gnd Vo
MOUNTING
HOLES
WIRING
OPENING
a33-9141
Vin - J4 -1 or J4 -4 24Vdc
Io - J4 -2 or J4 -5 4 -20mA output
C07201
Fig. 11 -- Space Relative Humidity Sensor Typical Wiring
Humidistat
The accessory humidistat provides the RTU Open insight
to the relative humidity in the space. The humidistat reads
the RH level in the space and compares it to its setpoint to
operate a dry contact. The humidistat is a dedicated input
on the configurable input 9 and tells the RTU Open when
the RH level is HIGH or LOW. The normal condition for
humidity is LOW. A normally open humidistat is the
factory default control for the Humidi-MiZer option. To
wire in the field:
SJ5--8 = 24 VAC source for dry contact
SJ5--7 = Signal input
NOTE: Not permitted for use on 48LC 07--26 units due
to same input as IGC input.
Single Enthalpy (Outdoor Enthalpy)
The outdoor enthalpy switch/receiver (33CSENTHSW)
senses temperature and humidity of the air surrounding
the device and calculates the enthalpy when used without
an enthalpy sensor. The relay is energized when enthalpy
is high (above 28 BTU/lb OR dry bulb temperature is
above 75_F) and de-energized when enthalpy is low
(below 27 BTU/lb AND dry bulb temperature is below
74.5_F). The enthalpy input is dedicated to input 8 and
tells the RTU Open when the outside air enthalpy is HIGH
or LOW. The normal condition for the enthalpy input is
HIGH. Enthalpy is configured on input 8 in the factory
when it is added as an option.
NOTE: The enthalpy calculation is done using an
average altitude of 1000 ft above sea level.
For field installation, refer to the enthalpy accessory
instructions. For wiring see below and Fig. 10. The RTU
Open board provides 24vac on one of the two loose grey
wires in the return air section of the rooftop near the
12-pin economizer plug. To determine the correct grey,
measure the voltage on the wires with power applied to
the unit. If 24-vac is sensed, then that is the grey wire that
is connected to the RTU Open board at J2-7. The other is
the signal for input 8, connect it to the LOW Enthalpy
terminal on the enthalpy switch/receiver. Tie into the
12-pin economizer plug on pin 4 or the black wire
connected to the actuator for the enthalpy’s GND
connection. Power can also be provided direct from the
unit transformer and J5 terminal on the RTU Open.
SJ2--7orJ5--2=24VACforenthalpyswitchpower
SJ2--6 or J5--1 = input signal
Differential Enthalpy
Differential enthalpy control requires both an enthalpy
switch/receiver (33CSENTHSW) and an enthalpy sensor
(33CSENTSEN). The enthalpy sensor must be installed in
the field as the factory can only provide single enthalpy.
The enthalpy sensor must be mounted in the return
airstream and calculates the enthalpy of the indoor air.
The relay is energized when the enthalpy detected by the
return air enthalpy sensor is less than the enthalpy at the
enthalpy switch/receiver. The relay is de-energized when
the enthalpy detected by the return air enthalpy sensor is
greater than the enthalpy at the enthalpy switch/receiver
(differential enthalpy control).
48---50LHTCQ---01T

12
SPAN
ZERO
4-20
mA
VAC
or
VDC
GND 0-5V
or
0-10V
123456
ON
J4-1 or J4-4 + 24 VDC Supply Voltage
J4-2 or J4-5 (-)4 to 20 mA Current Loop Output
to RTU Open
Relative Humidity Sensor
(Polarized Male Connector)
C12756
Fig. 12 -- Duct Relative Humidity Sensor Typical Wiring
To wire return air enthalpy sensor:--MP
Connect the 4-20 mA In terminal on the enthalpy switch/
receiver to the 4-20 mA Out terminal on the return air
enthalpy sensor. Connect the 24-36 VDC Out terminal on
the enthalpy switch/receiver to the 24-36 VDC In terminal
on the return air enthalpy sensor. (See Fig. 13.)
Fire Shutdown
The fire shutdown input is provided for unit shutdown in
response to a fire alarm or smoke detector. The fire
shutdown input is dedicated to input 5 and tells the RTU
Open when to shutdown due to smoke detection or fire
alarm system. The normal condition for fire shutdown is
there is no fire alarm. The unit may have factory installed
smoke detector(s); refer to the base unit installation
instructions for details on any adjustments required during
unit installation. Fire shutdown is always factory
configured for a normally open smoke detector.
For field installation of a smoke detector see instructions
for that specific accessory. See below and the
troubleshooting section for wiring at the unit’s Integrated
Staging Control (ISC) board (48/50LC 07--26) or Central
Terminal Board (CTB) (all 48/50TC(Q), all 48/50HC(Q),
and 04--06 48/50LC units).
SISC or CTB -- UNIT SHUTDOWN -- 24v OUT = 24
VAC source
SISC or CTB -- UNIT SHUTDOWN -- Smoke Alarm =
Signal input to RTU Open
NOTE: Input 5 can also be wired into J5--3.
Filter Status
The filter status accessory is a field-installed accessory.
This accessory detects plugged filters. When installing
this accessory, the unit must have a free input (input 3, 5,
8, or 9). One of the dedicated functions (Humidistat, Fire
shutdown, Enthalpy, or Compressor safety) must not be in
use to configure Filter Status. Refer to the configuration
section for details on configuring inputs for specific
functions and state. Refer to Fig. 1 for wire terminations
at J5.
Fan Status
The fan status accessory is a field-installed accessory.
This accessory detects when the indoor fan is moving air.
When installing this accessory, the unit must have a free
input (input 3, 5, 8, or 9). One of the dedicated functions
(Humidistat, Fire shutdown, Enthalpy, or Compressor
safety) must not be in use to configure Fan Status. Refer
to the configuration section for details on configuring
inputs for specific functions and state. Refer to Fig. 1 for
wire terminations at J5.
Remote Occupancy
The remote occupancy accessory is a field-installed
accessory. This accessory provides an input to change the
units occupancy status. When installing this accessory, the
unit must have a free input (input 3, 5, 8, or 9). One of the
dedicated functions (Humidistat, Fire shutdown, Enthalpy,
or Compressor safety) must not be in use to configure
remote occupancy. Refer to the configuration section for
details on configuring inputs for specific functions and
state. Refer to Fig. 1 for wire terminations at J5.
IGC Override
The IGC Override input is factory--installed for 48LC
07--26 gas heat units. This input provides an indication
that the gas valve is stuck open and the heat is still
operating after any call for heating has been dropped. This
function requires the use of input 9. Any of the other
dedicated functions (Humidistat, Fan Status, Filter Status,
Remote Occupancy, or Door Contact) will not be in use if
IGC Override is configured. Refer to the configuration
section for details on configuring inputs for specific
functions and state. Refer to Fig. 2 for wire terminations.
48---50LHTCQ---01T

13
C10821
Fig. 13 -- Enthalpy Switch and Sensor Wiring
Communication Wiring--Protocols
General
Protocols are the communication languages spoken by
control devices. The main purpose of a protocol is to
communicate information in the most efficient method
possible. Different protocols exist to provide different
kinds of information for different applications. In the BAS
application, many different protocols are used, depending
on manufacturer. Protocols do not change the function of
a controller; just make the front end user different.
The RTU Open can be set to communicate on four
different protocols: BACnet, Modbus, N2, and LonWorks.
Switch 3 (SW3) on the board is used to set protocol and
baud rate. Switches 1 and 2 (SW1 and SW2) are used to
set the board’s network address. See Fig. 14 and 15 for
protocol switch settings and address switches. The 3rd
party connection to the RTU Open is through plug J19.
See Fig. 16 for wiring. Refer to the RTU Open v3
Integration Guide for more detailed information on
protocols, 3rd party wiring, and networking.
NOTE: Power must be cycled after changing the SW1--3
switch settings.
i--VuRBuilding Automation System
i--Vu is a Carrier front-end and Building Automation
System (BAS). It is a web based network system that uses
a native BACnet over MS/TP communication protocol.
The speed of the network can range from 9600 to 76,800
baud. Open controllers communicate with a proprietary
language called Linkage in i--Vu. Linkage is established
automatically and allows the flow of specific data across
Open devices. Refer to i--Vu literature for more
information on i--Vu.
BACnetRMS/TP
BACnet Master Slave/Token Passing (MS/TP) is used for
communicating BACnet over a sub--network of
BACnet--only controllers. This is the default Carrier
communications protocol. Each RTU Open module acts as
an MS/TP Master. The speed of an MS/TP network can
range from 9600 to 76.8K baud. Physical Addresses can
be set from 01 to 99.
48---50LHTCQ---01T

14
SW3 Protocol Selection
PROTOCOL DS8 DS7 DS6 DS5 DS4 DS3 DS2 DS1
BACnet MS/TP
(Master) Unused OFF OFF OFF ON OFF Select Baud Select Baud
Modbus
(Slave) Unused OFF OFF ON ON OFF Select Baud Select Baud
N2
(Slave) Unused OFF OFF OFF ON ON OFF OFF
LonWorks Unused ON ON OFF ON OFF OFF ON
NOTE:
DS = Dip Switch
BACnet MS/TP SW3 example shown
Baud Rate Selections
BAUD RATE DS2 DS1
9600 OFF OFF
19,200 ON OFF
38,400 OFF ON
76,800 ON ON
C07166
Fig. 14 -- RTU Open SW3 Dip Switch Settings
C10815
Fig. 15 -- RTU Open Address Switches
C10816
Fig. 16 -- Network Wiring
Modbus
The RTU Open module can speak the Modicon Modbus
RTU Protocol as described in the Modicon Modbus
Protocol Reference Guide, PI----MBUS----300 Rev. J. The
speed of a Modbus network can range from 9600 to 76.8K
baud. Physical Addresses can be set from 01 to 99.
Johnson N2
N2 is not a standard protocol, but one that was created by
Johnson Controls, Inc. that has been made open and
available to the public. The speed of N2 network is
limited to only 9600 baud. Physical Addresses can be set
from 01 to 99.
LonWorks
LonWorks is an open protocol that requires the use of
Echelon’s Neuron microprocessor to encode and decode
the LonWorks packets. In order to reduce the cost of
adding that hardware on every module, a separate
LonWorks Option Card (LON--OC) was designed to
connect to the RTU Open.
This accessory card is needed for LonWorks and has to be
ordered and connected using the ribbon cable to plug J15.
The RTU Open’s baud rate must be set to 38.4k to
communicate with the LonWorks Option Card. The address
switches (SW1 & SW2) are not used with LonWorks.
48---50LHTCQ---01T

15
LON OC Rev.4
Net
1 2
J15
COMM
OPTION
Network
Connector
C12750
Fig. 17 -- LON--OC and LON Network Wiring
Local Access
Wall Mounted Equipment Touch
The Equipment Touch is a wall mounted interface used to
connect to the RTU Open to access the control
information, read sensor values, and maintenance. This is
an accessory interface that does not come with the RTU
Open controller. You wire the Equipment Touch to the
RTU Open’s J13 local access port. There are 2 password
protected levels in the display (User and Admin). See the
Equipment Touch Installation and Setup Guide for more
information. See Appendix A for navigation and screen
content.
Field Assistant
Field Assistant is a computer program included with the
purchase of the Tech Tool Kit (USB-TKIT). This is a field
Tech Tool to set-up, service, or download application
software to the RTU Open controller and includes a USB
Link Cable. The link cable connects a USB port to the J12
local access port. The Field Assistant’s menu structure is
similar and functions the same as i--VuR. See Fig. 18.
Connect to
computer’s
USB port
Connect to
the Local
Access port
USB Link Kit RTU Open
Access
Port
J12
P1 P1
P5 P5
LOCAL
ACCESS
PORT
GND GND
*Therm
mA
*Therm
mA
UI-10
UI-11
SW3
on
COMM
OPTION
CR2032
+
-
SW1 SW2
MSB LSB
TXRX
+12 DVC
Rnet-
Rnet+
GND
RNET
J12
J13
J15
J20
C14131
Fig. 18 -- PC Running Field Assistant
48---50LHTCQ---01T

16
START--UP
IMPORTANT: Follow the base unit’s start-up sequence
documented in its specific instructions. Use the base unit’s
start-up check list when performing the start-up. At the
end of this manual there is an additional RTU Open
Start-up Sheet to be completed and included with the base
unit check list.
Besides the base unit start-up, there are a few steps to take to
properly start-up the controls. RTU Open’s Service Test
function should be used to assist in the base unit start-up and
also allows verification of output operation. Controller
configuration is also part of start-up. This is especially
important when field accessories have been added to the
unit. The factory pre-configures options installed at the
factory. There may also be additional installation steps or
inspection required during the start-up process.
Additional Installation/Inspection
Inspect the field installed accessories for proper
installation, making note of which ones do or do not
require configuration changes. Inspect the RTU Open’s
Alarms for initial insight to any potential issues. See
troubleshooting section for alarms. Inspect the SAT sensor
for relocation as intended during installation. Inspect
special wiring as directed below.
Power Exhaust Relay Power
The relay used by the RTU Open board to control power
exhaust is a dry contact which means it does not have
24vac. This 24vac must be connected to the relay to allow
it operate the power exhaust relay in the PE accessory. A
24vac source should be provided to the J11-2 pin on the
RTU Open. This can be provided by the unit’s transformer
from various sources. The “R” terminal on the unit’s
Integrated Staging Control (ISC) board (on 48/50LC
07--26 units) or the “R” terminal on the Central Terminal
Board (CTB) (on all 48/50TC(Q), 48/50HC(Q) and 04--06
48/50LC units) is a logical source.
NOTE: Factory installed power exhaust comes
pre--configured and does not require routing 24vac as
described above. This factory installed option is only
available on the following vertical air flow units:
48/50TC(Q) 17--30, 48/50HC 16--30, and 48/50LC 14--26.
Service Test
The Service Test function can be used to verify proper
operation of compressors, heating stages, indoor fan,
power exhaust fans, economizer, and dehumidification.
Use of Service Test is recommended at initial system start
up and during troubleshooting. See Appendix A for
Service Test Mode table.
Service Test mode has the following changes from normal
operation:
SOutdoor air temperature limits for cooling circuits,
economizer, and heating are ignored.
SNormal compressor time guards and other staging
delays are ignored.
SThe status of Alarms (except Fire and Safety chain) is
ignored, but all alerts and alarms are still broadcasted
on the network.
Service Test can be turned ON/OFF from Field Assistant,
from the network, or from the Equipment or System
Touch. Once turned ON, other entries may be made with
the display or through the network. To turn Service Test
on, change the value of Test Mode to ON, to turn Service
Test off, change the value of Test Mode to OFF.
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
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 when Service Test is set to
Disable. In addition, Service Test also returns to Disable
after 1 hour.
Fan Test
This point allows the board’s fan output to be manually
turned On (Enable) and Off (Disable). Other test points
that require the fan for operation will automatically turn
the fan on and this point will still show “Disable.” Fan test
can operate simultaneously with other Service Test Points.
For units equipped with variable speed fans, the fan test
will operate the unit’s fan at minimum VFD output speed.
High Speed Fan Test
Use the High Speed Fan Test to activate and deactivate
the Supply Fan (BO--1) output. Note that this output is
only applicable if Fan Control is set to Two Speed and
Unit Type is NOT equal to HP O/B Ctrl.
Compressor 1 and Compressor 2 Test
The compressor test points are used to change output
status for the individual compressors. Compressor starts
are not staggered. The fan and heating service test outputs
are reset to “Disable” for the compressor service tests.
The Indoor fan and outdoor fans are controlled normally
to maintain proper unit operation. All normal cooling
alarms and alerts are functional.
NOTE: For the LC WeatherExpert size 07--26 units, each
compressor stage can be operated independently.
Heat 1 and Heat 2 Test
The heat test points are used to change output status for
the individual heat stages, gas or electric. The fans and
cooling service test outputs are reset to “Disable” for the
heat service tests. Indoor and outdoor fans are controlled
normally to maintain proper unit operation. All normal
heating alarms and alerts are functional.
Dehumidification Test
For units with the factory Reheat option, the dehumidifica-
tion relay is used to change the output status to operate the
circuits in different Reheat modes. Dehumidification relay
on by itself puts all circuits running in Hot Gas Reheat dehu-
midification mode; dehumidification relay on and the cool-
ing test (compressor test relays) on puts unit and or individu-
al circuits in subcooling dehumidification mode. The fans
and heating service test outputs are reset to “Disable” for the
dehumidification service test. Indoor and outdoor fans are
controlled normally to maintain proper unit operation. All
normal cooling/dehum alarms and alerts are functional.
48---50LHTCQ---01T

17
Power Exhaust Test
This point allows the board’s power exhaust (PE) output
to be manually turned On (Enable) and Off (Disable).
Power Exhaust test can operate simultaneously with other
Service Test Points.
Economizer Test
This point allows the board’s economizer output to be
manually controlled from 0 to 100 % Open. Economizer test
can operate simultaneously with other Service Test Points.
VFD Speed Test
This point activates the board’s 0--10vdc analog output
that controls the unit’s supply fan VFD speed.
NOTE: This output is only applicable if Fan Control is
set to Variable Speed.
NOTE: Service Test Mode does not timeout. Be sure to
turn off test mode or cycle power to the RTU to return to
normal operation.
Configuration
The RTU Open controller’s configuration points effect the
unit’s inputs and operation. Review and understand the
meaning and purpose of each configuration point before
changing it from the factory default value. Use the RTU
Open Start-up Sheet during configuration; fill in changed
values if changed from factory default. There are three main
configurations menus: SETPOINT, UNIT, and SERVICE.
Each configuration point is described below under its
according menu. See Appendix A for menu structure.
Setpoint
Occupied Heating Setpoint -- The heating setpoint the
controller maintains during the occupied period.
Range = 40 - 90_F Default = 70_F
Occupied Cooling Setpoint – The cooling setpoint the
controller maintains during the occupied period.
Range = 55 - 99_F Default = 76_F
Unoccupied Heating Setpoint – The heating setpoint the
controller maintains during the unoccupied period.
Range = 40 - 90_F Default = 55_F
Unoccupied Cooling Setpoint – The cooling setpoint the
controller maintains during the unoccupied period.
Range = 45 - 99_F Default = 90_F
Effective Heating Setpoint – The current setpoint value
heating operation will control to.
Range = 0 - 120_F
Effective Cooling Setpoint – The current setpoint value
cooling operation will control to.
Range = 0 - 120_F
Optimal Start - The earliest time prior to occupancy, at
which the Optimal Start function may begin to adjust the
effective setpoints. Setting this to 0 will disable optimal start.
Range = 0 - 4 hours Default = 4 hour
Occ Relative Humidity Setpoint – The space RH setpoint
the controller maintains during the occupied period.
Range = 0 to the Unocc RH setpoint
Default 60%
Unocc Relative Humidity Setpoint – The space RH
setpoint the controller will maintain during the
unoccupied period.
Range = 30-100% Default = 95%
DCV Max Ctrl Setpoint – The difference between indoor
and outdoor CO2level which results in maximum
ventilation damper position.
Range = 0-9999ppm Default = 650ppm
Power Exhaust Setpoint –Usedtodeterminewhenthe
power exhaust operation will begin. This setpoint is based
on the maximum fan speed. When the economizer
position opens above this point, power exhaust operation
will begin and when the damper position falls 5% below
this point, the power exhaust will shutdown.
Range = 20-90% Default = 50%
NOTE: This setpoint is automatically adjusted if the Fan
Type is set to Variable Speed or 2--Speed in order to
maintain proper building pressure. The actual calculated
value, Calculated PE Setpoint, is shown in
MAINTENANCE.
NOTE: This point is only used when Continuous
Occupied Exhaust = NO
Unit
Fan Mode – Sets the operation of the indoor fan when not
in cooling or heating mode. Refer to fan operation for
details on each operation.
Range = Auto, Continuous, or Always On
Default = Continuous
Power Fail Restart Delay -- Sets how long the controller
delays normal operation after the power is restored.
Typically used to prevent excessive demand when
recovering from a power failure
Range = 0 - 30 sec Default = 5 sec
Fan Off Delay – Time delay in which the fan will
continue run after being commanded off.
Range = 10 -300 sec Default = 90 sec
Minimum Cooling SAT – The supply air temperature
must remain above this value to allow cooling with the
economizer and/or compressors. There is 5_Fplusand
minus deadband to this point. If the SAT falls below this
value during cooling a compressor stage will be removed
and/or the economizer will return to minimum position.
Range = 45 - 75_F Default = 50_F
Maximum Heating SAT – The supply air temperature must
remain below this value to allow heating. There is 5_Fplus
and minus deadband to this point. If the SAT falls below this
value during heating the heat stages will begin to decrease
until the SAT has dropped below this value.
Range = 85 - 150_F Default = 120_F
Vent Dmpr Pos / DCV Min Pos – Minimum damper
position for ventilation during the occupied period when
the fan is operating at full speed.
Range = 0 -- 100% open Default = 20% open
Economizer Purge Min Pos – The damper position used
during the Pre--Occupancy Purge cycle prior to occupancy
when Pre--Occupancy purge is active
Range = 0 -- 100% open Default = 40% open
Low Fan Econ Min Pos – The minimum damper position
used for ventilation during the occupied period when the
fan is operating at it’s lowest speed.
Range = 0 -- 100% open Default = 33% open
NOTE: This setpoint is only applicable if the Fan Type is
set to Variable Speed or 2--Speed.
48---50LHTCQ---01T

18
DCV Max Vent Damper Pos – This is the greatest
position the economizer can open to while trying to
control the indoor air quality levels
Range = 0 -- 75% open Default = 50% open
Supply Fan Service Alarm Timer – The timer set for the
Supply Fan Runtime Alarm. After the number of hours set
on this point is exceeded the corresponding alarm will be
generated, and must be manually cleared in the maintenance
menu after the maintenance has been completed. The timer
will then begin counting its runtime again for the next due
maintenance.
Range = 0 to 9999 hr Default = 600 hr
NOTE: If set to 0 hr this setpoint is disabled and its alarm
will never be generated.
Comp 1 Service Alarm Timer – The timer set for the
Compressor 1 Runtime Alarm. After the number of hours
set on this point is exceeded the corresponding alarm will
be generated, and must be manually cleared in the
maintenance menu after the maintenance has been
completed. The timer will then begin counting its runtime
again for the next due maintenance.
Range = 0 to 9999 hr Default = 0 hr
NOTE: Default = 0 hours, if set = 0 hr this point is
disabled and its alarm will never be generated.
Comp 2 Service Alarm Timer – The timer set for the
Compressor 2 Runtime Alarm. After the number of hours
set on this point is exceeded the corresponding alarm will
be generated, and must be manually cleared in the
maintenance menu after the maintenance has been
completed. The timer will then begin counting its runtime
again for the next due maintenance.
Range = 0 to 9999 hr Default = 0 hr
NOTE: Default = 0 hours, if set = 0 hr this point is
disabled and its alarm will never be generated.
Filter Service Alarm Timer – The timer set for the Dirty
Filter Alarm. After the number of hours set on this point is
exceeded the corresponding alarm will be generated, and
must be manually cleared in the maintenance menu after the
maintenance has been completed. The timer will then begin
counting its runtime again for the next due maintenance.
Range = 0 to 9999 hr Default = 600 hr
NOTE: Default = 600 hours, if set = 0 hr this point is
disabled and its alarm will never be generated.
Pushbutton Override – Set to enable or disable the push-
button override function of the locally installed space sensor.
Range = Disable/Enable Default = Enable
Door Alarm Delay -- Determines the amount of delay
before a door alarm is generated.
Range = 0 to 3600 seconds Default = 60 seconds
Setpoint Adjustment – Set to enable or disable the setpoint
adjustment function of the locally installed space sensor.
Range = Disable/Enable Default = Enable
Setpoint Adjustment Range -- Sets the slider range of a
space sensor (with built in function). The slider is used to
offset the control setpoint
Range = 0 to 5_F Default = 5_F
Cooling Lockout Temperature -- This defines the
minimum outdoor air temperature that cooling mode can
be enabled and run. If the OAT falls below this number
during cooling the compressors will be de-energized
Range = --65 - 80_F Default = 45_F
Economizer High OAT Lockout Temp – If the outdoor
air temperature rises above this value, economizer cooling
will be disabled and dampers will return and stay at
minimum position.
Range = 55 - 80_F Default = 75_F
Heating Lockout Temperature – This defines the
maximum outdoor air temperature that heating mode can
be enabled and run. If the OAT rises above this number
during heating the heat stages will be de-energized.
Range = 35 -- 150_F Default = 65_F
Pre--Occupancy Purge -- Enables or disables the use of a
purge cycle immediately prior to the start of a scheduled
occupied period.
Range = Enable/Disable Default = Disable
Purge Time -- The maximum amount of time used for a
pre--occupancy purge.
Range = 0 to 240 minutes Default = 60 minutes
Unocc Free Cool Enable – Set to enable or disable the
economizer for night time free cooling (NTFC) operation.
Range = Disable/Enable Default = Disable
Setpoint Separation – Sets the minimum separation gap
in which setpoints can be set.
Range = 2 - 10_F Default = 5_F
Occupancy Source – Tells the controller which method of
occupancy control to use in determining occupancy of the
rooftop. Refer to Occupancy in the operation section for
detail on each specific operation function.
Range = Always Occupied, BACnet Schedule,
BAS On/Off, or Remote Occ Input
Default =Always Occupied
Inputs
Input 1 Function – This input is an analog input and can
be configured to be one of four different inputs: No
Sensor, IAQ Sensor, OAQ Sensor, or Space RH Sensor.
Input 1 is wired to pin J4--4,5,6.
Default = No Sensor
Input 2 Function – This input is an analog input and can
be configured to be one of four different inputs: No
Sensor, IAQ Sensor, OAQ Sensor, or Space RH Sensor.
Input 2 is wired to pin J4--1,2,3.
Software Default = No Sensor
Factory Default = IAQ Sensor with factory
installed CO2sensor
NOTE: For Inputs 1 & 2, if using Carrier air quality
sensors do not use 24Vdc from RTU Open board. External
24Vdc power supply required.
Input 3 -- This input is a discrete input and can be
configured to be one of six different functions: No
Function, Compressor Safety, Fan Status, Filter Status,
Remote Occupancy, or Door Contact. This input can also
be configured to be either a Normally Open (N/O) or a
Normally Closed (N/C) switch. Input 3 is factory wired to
pin J1-2. Field accessories can be wired to its parallel pin
J5-5. Factory Default = Compressor Safety and N/O
48---50LHTCQ---01T

19
Input 5 -- This input is a discrete input and can be
configured to be one of six different functions: No Function,
Fire Shutdown, Fan Status, Filter Status, Remote Occupancy,
or Door Contact. This input can also be configured to be
either a Normally Open (N/O) or a Normally Closed (N/C)
switch. Input 5 is factory wired to pin J1-10. Field
accessories can be wired to its parallel pin J5-3.
Software Default = Fire Shutdown and N/C
Factory Default = Fire Shutdown and N/O
Input 8 -- This input is a discrete input and can be
configured to be one of six different functions: No
Function, Enthalpy Switch, Fan Status, Filter Status,
Remote Occupancy, or Door Contact. This input can also
be configured to be either a Normally Open (N/O) or a
Normally Closed (N/C) switch. Input 8 is factory wired to
pin J2-6. Field accessories can be wired to its parallel pin
J5-1.
Software Default= Enthalpy Switch and N/O
Factory Default = No Function and N/O without
factory installed enthalpy sensor
Input 9 -- This input is a discrete input and can be
configured to be one of seven different functions: No
Function, Humidistat, Fan Status, Filter Status, Remote
Occupancy, Door Contact, or IGC Override. This input
can also be configured to be either a Normally Open
(N/O) or a Normally Closed (N/C) switch. Input 9 is
factory and field wired to pin J5-7.
Factory Default = Humidistat and N/O
NOTE: For 48LC 07--26 Units (gas heat units) this decision
is automatically set to IGC Override and is factory wired.
Space Sensor Type – This tells the controller what type
of space sensor is installed to run the unit. The four types
that can be used are: a standard 10k Type II thermistor
(T55), sensor with a setpoint offset slider bar (T56), or a
communicating sensor (SPT Sensor) and, ZS Sensor.
Range = T55, T56 (Use for T59), SPT Sensor,
or ZS Sensor
Default = T55
ZS Sensor Type -- The type of local space temperature
sensor. Range = ZS Base, ZS Plus, ZS Pro
Default = None
T5x Override Duration – Sets the override time duration
the unit will change from unoccupied to occupied when
the override button is pushed on the space sensor.
Range = 0-24 hours Default = 1 hour
Rnet Port -- input for communicating sensor or
Equipment Touch Terminal J13 -- 1, 2, 3, 4
Range = SPT Sensor, ZS Sensor, or
Equipment Touch
Default= None
Service Configuration
Unit Type – This tells the control what type of unit it is
controlling. Heat/Cool refers to gas and electric heat units.
LC WeatherExpert refers to a special 3 stage/2 compressor
unit. HP O/B Ctrl refers to a heat pump unit which
requires reversing valve control. HP Y1/W1 Ctrl refers to
a heat pump unit whose reversing valve is built in to the
cooling or heating call. This decision is factory configured
for the specific unit type as supplied.
NOTE: When unit type is set to LC WeatherExpert other
configuration settings in the Service Configuration menu
will become hidden from user’s view. The configurations
that become hidden include Compressor Stages, Face Split
Coil, Fan Control.
Compressor Stages – This refers to the number of
mechanical cooling stages available on a specific unit. For
LC size 07--26 units this setting is “Three Stage” and is
not a visible menu configuration.
Factory Default = “Three Stage” for LC size
07--26 units
Economizer Exists – This indicates if there is an
economizer installed on the unit.
Factory Default = NO if no economizer, or YES if
there is an economizer installed
Fan Control -- This refers to the type of fan control for the
given unit. If Unit Type is selected to LC WeatherExpert,
then this is set to Variable Speed, and is not a visible menu
configuration.
Factory Default = Variable Speed for LC size
07--26 units.
VFD Input -- Defines the electrical control signal used by
the VFD’s input. Applies to Variable Speed fan control only
(LC size 07--26 units by default).
Range = 2--10VDC or 0--10VDC
Factory Default = 2--10 VDC
Max VFD Output --ThemaximumVFDsignalRTUOpen
supplies to the VFD as a percentage of its range. The
balancer can set this to adjust the unit’s maximum airflow.
Applies to Variable Speed fan control. (LC size 07--26 units
by default)
Range = 33--100% Default = 100%
Min VFD Output -- The minimum VFD signal RTU Open
supplies to the VFD as a percentage of its range. The
balancer can set this to adjust the unit’s minimum airflow.
Applies to Variable Speed fan control only (LC size 07--26
by default)
Range = 33--100% Default = 40%
Dehum Min VFD Output -- The minimum output signal
supplied by RTU Open during dehumidification as a
percentage of its range. Applies to Variable Speed fan
control only (LC size 07--26 by default)
Range = 50--100% Default = 100%
Stage 1 SAT Setpoint -- The VFD Supply Air Setpoint
during stage 1 cooling. Must be at least 4_F greater than
Minimum Cooling SAT parameter
Range = 45 -- 75_F Default = 57_F
Stage 2 SAT Setpoint -- The VFD Supply Air Setpoint
during stage 2 cooling. Must be at least 4_F greater than
Minimum Cooling SAT parameter
Range = 45 -- 75_F Default = 57_F
Stage 3 SAT Setpoint -- The VFD Supply Air Setpoint
during stage 3 cooling. Must be at least 4_F greater than
Minimum Cooling SAT parameter
Range = 45 -- 75_F Default = 56_F
Heat Type – Indicates the type of heat which is installed in
the unit. Electric is any unit without gas and a Gas unit is
one which requires gas input for heating.
Factory Default = Gas for gas units and Electric for
all other units (cooling only units and heat pumps)
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20
Number of Heat Stages – Indicates how many heat
stages are available for use. See configuration in
Appendix A for details on specific unit configuration.
Factory Default =1 for single heat stage units
2 for dual stage units
0 for cooling only units
Continuous Occupied Exhaust – This point tells the
controller when to run the power exhaust if equipped on
the unit.
If set to YES, the power exhaust will be on all the time
when in occupied mode and will be off when in
unoccupied mode. If set to NO the power exhaust will be
controlled by the Power Exhaust Setpoint.
Default = NO
RH Control -- Enables dehumidification control if an RH
sensor is available and the unit has the Humidi--MiZerR
dehumidification option installed.
Range = Disable/Enable
Default = Disable
(Enabled with Humidi--MiZer option)
DCV Control -- Enables demand controlled ventilation
(DCV)ifvalidCO
2sensor value is available and the unit
has an economizer installed.
Range = Disable/Enable
Default = Disable
System Space Temperature -- The network space
temperature value that the controller is using for control
(if applicable).
Range = N/A Default = --999.0_F
System Space RH -- The network relative humidity value
that the controller is using for control (if applicable)
Range = N/A Default = --999.0%
System Space AQ -- The network indoor air quality (CO2)
value that the controller is using for control (if applicable)
Range = N/A Default = --999.0 PPM
System Cool Demand Level -- The system cool demand
level being received over the network
Range = N/A Default = 0--3
System Heat Demand Level -- The system heat demand
level being received over the network
Range = N/A Default = --0--3
System Outdoor Air Temperature -- Allows the outdoor
air temperature value to be network readable when
enabled. Requires RTU Open to be equipped with an
outdoor air temperature sensor
Range = N/A Default = --999.0_F
System Outdoor AQ -- Allows network readable value of
OAQ for calculation during differential OAQ CO2levels
and IAQ CO2levels to drive the IAQ control
Range = N/A Default = --999.0 PPM
System Fire / Smoke -- Allows network readable fire/smoke
signal to invoke shutdown action in the RTU
Range = N/A Default = OFF
Indoor CO2Sensor Value @ Min mA – Sets the indoor
CO2value when the board reads 4 mA at input 1 or 2.
Range = 0 to 9999 ppm Default = 0 ppm
Indoor CO2Sensor Value @ Max mA – Sets the indoor
CO2value when the board reads 20 mA at input 1 or 2.
Range = 0 to 9999 ppm Default = 2000 ppm
Outdoor CO2Sensor Value @ Min mA – Sets the outdoor
CO2value when the board reads 4 mA at input 1 or 2.
Range = 0 to 9999 ppm Default = 0 ppm
Outdoor CO2Sensor Value @ Max mA – Sets the outdoor
CO2value when the board reads 20 mA at input 1 or 2.
Range = 0 to 9999 ppm Default = 2000 ppm
NOTE: The indoor and outdoor min and max mA setting
are used to set the linear curve of mA vs. PPM.
OPERATION
The RTU Open will control the compressors, economizer
and heating outputs based on its space temperature input
and setpoints. It can also be controlled by a building
control system or zoning system. An optional CO2IAQ
sensor mounted in the space can influence the economizer
minimum position. The RTU Open has a hardware clock
that can allow scheduling for stand-alone operation. The
RTU Open’s default is to control to occupied setpoints all
the time, until a type of occupancy control is set. The
following sections describe the operation for the functions
of the RTU Open.
Occupancy
Occupancy is the fundamental overall control of
equipment. The unit can be in one of two states: Occupied
or Unoccupied. These are usually referred to as periods
because they represent periods of any given day. Before
RTU Open can operate specific functions of the
equipment it is installed on, occupancy must be
determined. There are four different ways RTU Open can
determine occupancy. These are described below and
selected by the configuration point Occupancy Source.
Always Occupied (Default)
The unit will not determine occupancy and continuously
run in the occupied state or period. RTU Open ships from
the factory with this setting to allow immediate operation.
BACnetRSchedule
When Occupancy Source is set to BACnet Schedule, RTU
Open will use a schedule to change occupancy based upon
a day of week and a time period. Local time and date
should be set in the RTU Open for this function to operate
properly. This function applies if setting a local schedule
in the RTU Open or if applying the unit to an i--VuROpen
Building Automation System or an Open zoning system.
An Open network schedule can override a local schedule
within the unit. A space sensor push button override is
only available when running a local or Open schedule.
The push button will override an unoccupied period to
occupied for the specified time duration.
BAS On/Off
When Occupancy Source is set to BAS On/Off, RTU
Open follows occupancy based on an On/Off command to
the BAS ON/OFF software point. An on command sets
the occupancy to occupied, and an off command sets it to
unoccupied. The Building Automation System can be
speaking BACnet, Modbus, N2, or LON and is writing to
the BAS On/Off point in the open protocol point map.
Remote Occ Input
When Occupancy Source is set to Remote Occ Input, RTU
Open follows occupancy based on the remote occupancy
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