Carrier 50HCQ04-12 User Manual

48/50TC04 ---28, 50TCQ04---12
48/50HC04---14, 50HCQ04---12
Factory Installed Option
R T U --- O P E N

Controls, Start---Up, Operation

and Troubleshoot ing Instruct io ns

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(s) (IAQ and OAQ) 6......................

CO

2

Relative Humidity Sensors 8..........................

Installing Discrete Inputs 8.............................

Compressor Safety 8................................

Humidistat 8......................................

Single Enthalpy (Outdoor Enthalpy) 8..................

Differential Enthalpy 8..............................

Fire Shutdown 9...................................

Filter Status 9......................................

Fan Status 9.......................................

Remote Occupancy 9................................

Communication Wiring--Protocols 10.....................

General 10........................................

I--Vu OPEN 10....................................

BACnet MS/TP 10.................................

Modbus 11.......................................

Johnson N2 11.....................................

LonWorks 11......................................

Local Access 12....................................

START--UP 13........................................

Additional Installation/Inspection 13.....................

Service Test 13......................................

Fan Test 13.......................................

Compressor 1 and Compressor 2 Test 13.................

Heat 1 and Heat 2 Test 13............................

Reversing Valve Test 13.............................

Dehumidification Test 14.............................

Power Exhaust Test 14..............................

Economizer Test 14.................................

Analog Output 2 Test 14.............................

Configuration 14....................................

Setpoint 14.......................................

Unit 14..........................................

Inputs 15.........................................

Service 16........................................

Clockset 16.......................................

USERPW 17......................................

OPERATION 17......................................

Occupancy 17.......................................

Indoor (Supply) Fan 17...............................

Cooling 18.........................................

Economizer 18......................................

Power Exhaust 18....................................

Heating 18.........................................

Indoor Air Quality 19.................................

Dehumidification 19..................................

Demand Limit 19....................................

Unoccupied Free Cooling 19...........................

Optimal Start 20.....................................

Fire Shutdown 20

Compressor Safety 20.................................

Fan Status 20.......................................

Filter Status 20......................................

Door Switch 20......................................

Linkage 20.........................................

TROUBLESHOOTING 21..............................

General 21.........................................

Thermistor Troubleshooting 21.........................

Software Version 21..................................

Communication LED’s 22.............................

Alarms 24..........................................

Third Party Networking 26.............................

APPENDIX A -- USER INTERFACE MENUS 27............

APPENDIX B -- THIRD PARTY POINTS LIST 36...........

RTU --OPEN START --UP SHEET 41......................

....................................

Copyright 2010 Carrier Corp. D 7310 W. Morris St. D Indianapolis, IN 46231 Printed in U.S.A. Edition Date: 08/10

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.

Catalog No:48---50HCTQ ---01T

Replaces: NEW

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.

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

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 disconnected.

. When you see this symbol on the unit and in

!

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--Vu Open 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: BACnet, Modbus, Johnson N2 and
LonWorks. (See Fig. 1.)

Carrier’s diagnostic display tools such as Field Assistant
BACview6 Handheld or Virtual BACview can be used
with the RTU--OPEN controller. Access is available via a
5--pin J12 access port.

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
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.

!

WARNING

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.

2

Fig. 1 -- RTU--OPEN Control Module

3

C10818

Table 1 – RTU--OPEN Inputs and Outputs

POINT NAME

Space Temp / Zone Temp zone_temp AI (10K Thermistor) J 2 0 --- 1 , 2
Supply Air Temperature sa_temp AI (10K Thermistor) J 2 --- 1 , 2
Outdoor Air Temperature oa_temp AI (10K Thermistor) J2 --- 3 , 4
Space Temperature Offset Pot stpt_adj_offset AI (100K Potentiometer) J 2 0 --- 3
Safety Chain Feedback safety_status DI (24 VAC) J 1 --- 9
Compressor Safety Status comp_status DI (24 VAC) J 1 --- 2
Fire Shutdown Status firedown_status DI (24 VAC) J 1 --- 1 0
Enthalpy Status enthalpy_status DI (24 VAC) J 2 --- 6
Humidistat Input Status humstat_status DI (24 VAC) J 5 --- 7

Indoor Air CO2 iaq A I ( 4 --- 2 0 m a )
Outdoor Air CO2 oaq A I ( 4 --- 2 0 m a )
Space Relative Humidity space_rh A I ( 4 --- 2 0 m a )
Supply Fan Status* sfan_status DI (24 VAC)
Filter Status* filter_status DI (24 VAC)
Door Contact Input* door_contact_status DI (24 VAC)
Occupancy Contact* occ_contact_status DI (24 VAC)

Economizer Output econ_output A O ( 4 --- 2 0 m a ) J 2 --- 5
SupplyFanRelayState sfan DO Relay (24VAC , 1A) J 1 --- 4
Compressor 1 Relay State comp_1 DO Relay (24VAC , 1A) J 1 --- 8
Compressor 2 Relay State comp_2 DO Relay (24VAC , 1A) J 1 --- 7
Heat Stage 1 Relay State heat_1 DO Relay (24VAC , 1A) J 1 --- 6
Heat Stage 2 Relay State heat_2 DO Relay (24VAC , 1A) J 1 --- 5
Power Exhaust Relay State pexh DO Relay (24VAC , 1A) J 1 1 --- 3
Dehumidification Relay State dehum DO Relay (24VAC, 1A) J 1 1 --- 7 , 8

* These inputs (if installed) take the place of the default input on the specific channel

Pa r a l l e l pin 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 in s t a l l a t i o n .

Refer to the input configuration and accessory sections for more detail.

BACnet OBJECT

NAME

DEDICATED INPUTS

CONFIGURABLE INPUTS

TYPE OF I/O

OUTPUTS

CONNECTION PIN

NUMBER(S)

J 4 --- 2 o r J 4 --- 5

J 5 --- 1 o r J 5 --- 3 o r

J55orJ5---7

Sensors and Accessories

The RTU-OPEN controller is configurable with the
following field-supplied sensors:

NOTE: Supply air temperature sensor (33ZCSENSAT) is
factory-installed.

S Space temperature sensor (SPS, SPPL, SPP, SPPF,

33ZCT55SPT, 33ZCT56SPT, or 33ZCT59SPT

S Indoor air quality sensor (33ZCSENCO2,

33ZCT55CO2, 33ZCT56CO2) required for demand
control ventilation.

S Outdoor air quality sensor (33ZCTSENCO2)

aspirator box (C33ZCCASPCO2) required for CO

S CO

2

return duct/outside air applications

S Outdoor air enthalpy switch (33CSENTHSW)
S Return air enthalpy sensor (33CSENTSEN) required for

differential enthalpy control

S Space relative humidity sensor (33ZCSENSRH-01)
S Duct relative humidity (33ZCSENDRH-01)
S Humidistat (--HL--38MG-029)
S Smoke Detectors (CRSMKSEN002A00,

CRSMKKIT002A00)

S Fan and/or Filter Status (CRSTATUS001A00,

CRSTATUS005A00)

User Interfaces

S BACview 6 Handheld (BV6H)

S Virtual BACview (USB-L or USB-TKIT required)
S Field Assistant (USB-TKIT required)

Install Analog Sensors

Supply Air Sensor (SAT)

The factory supplies the discharge (supply) air sensor with
the unit and is pre--wired. On 04-16 size units, the SAT is
secured to the unit’s supply duct opening. This sensor
must be relocated into the supply duct during unit
installation. On 17-30 size units, the SAT is mounted
through the side of the heat chamber below the fan deck,
and does NOT require relocation.

2

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 SPT sensors available from Carrier,
resistive input non-communicating (T55, T56, and T59)
and Rnet communicating (SPS, SPPL, SPP, and SPPF)
sensors. Each type has a variety of options consisting of:
timed override button, set point adjustment, a LCD
screen, 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.

4

Fig. 2 -- Typical Factory Option Wiring

5

C10819

Resistive Non--Communicating Sensor Wiring

For sensor with setpoint adjustment up to 500 ft (152m),
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. 3 and 4 for
typical connections at the sensor.

S J20-1 = temperature sensor input (SEN)
S J20-2 = sensor common
S J20-3 = Setpoint adjustment input (SET)

NOTE: See Fig. 5 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.

2

3

SEN

SW1

Cool Warm

Fig. 3 -- Space Temperature Sensor

Typical Wiring (33ZCT56SPT)

OR SET SEN

OPB COM- PW R+

45

BRN (COM)

BLK (STO)

BLU (SPT)

61

SET

BLK
(T56)

BRN (GND)
BLU (SPT)

SENSOR WIRING

JUMPER
TERMINALS
AS SHOWN

SENSOR

WIRING

C07131

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:

S 1-4 SPS sensor(s)
S 1 SPPL, SPP, or SPPF sensor
S 1-4 SPS sensor(s), and 1 SPPL, SPP, or SPPF sensor
S Any of the above combinations, plus up to 2

6

BACview

NOTE: Additional SPS sensors and BACview

s

6

must be

addressed. Use the jumpers on the SPS sensor’s circuit

6’

board and refer to the BACview

s 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. 6 shows sensor
Rnet wiring.

S RNET -- 1 = Signal ground (GND)
S RNET -- 2 = Signal (Rnet+)
S RNET -- 3 = Signal (Rnet--)
S RNET -- 4 = Power (+12v)

CO2Sensor(s) (IAQ and OAQ)

The indoor air quality (IAQ) and outdoor air quality

2

Sensor

) levels. This

2

(IAQ) sensor

sensor

2

(OAQ) sensors monitor carbon dioxide (CO
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 CO
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 CO

sensor on the side of the economizer

2

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 CO

sensor for electrical requirements

2

and terminal locations. RTU-OPEN configurations must
be changed after adding a CO
7 for typical CO

sensor wiring.

2

sensor. See below and Fig.

2

S J4--2 or J4--5 = 4--20mA signal input
S J4--3 or J4--6 = signal common

NOTE: The factory used J4-2&3 for CO
inputs.

Combination Temperature and CO

2

If using a combination temperature and CO
(33ZCT55CO2 or 33ZCT56CO2), refer to the installation
instructions provided with the sensor.

2

24 VAC

NOTE: Must use a separate isolated transformer.

Fig. 4 -- Space Temperature Sensor

Typical Wiring (33ZCT59SPT)

POWER
WIRING

6

RED

BLK

RED

BLK

J20

J20

1

2

1

2

RED

BLK

LEGEND

Factory Wiring

Field Wiring

RED

BLK

RED

BLK

SENSOR 1 SENSOR 2 SENSOR 3 SENSOR 4

RED

BLK

SPACE TEMPERATURE AVERAGING — 4 SENSOR APPLICATION

BLK

BLK

SENSOR 1

RED

SENSOR 4

RED

RED

BLK

SENSOR 2

RED

BLK

SENSOR 5

RED

BLK

RED

BLK

SENSOR 3

RED

BLK

SENSOR 6

RED

BLK

SENSOR 7

SENSOR 8

SPACE TEMPERATURE AVERAGING — 9 SENSOR APPLICATION

Fig. 5 -- Space Temperature Averaging

24 VAC

HG

OR

+

-

24 VDC

2

1

SENSOR 9

C07133

+

0-10VDC

-

SIG COM (J4-6)

+

4-20mA (J4-5)

ALARM

NC
COM

RELAY

}

CONTACTS

NO

5

1

4

32

7

6

8

Fig. 6 -- Typical Rnet Communication Sensor Wiring

C07134

Fig. 7 -- Indoor/Outdoor Air Quality (CO2)Sensor

33ZCSENC02) -- Typical Wiring Diagram

C10820

7

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-Mizert option 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 Fig. 8 and 9 for typical RH
sensor wiring.

S J4--1 or J4--4 = 24vdc loop power
S J4--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 is usually provided by a
Compressor Lock-Out (CLO) device. 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 Low Voltage terminal Board (LVTB).

NOTE: Input 3 can also be wired into J--5.

MOUNTING
HOLES

Io

Gnd

Vin

Vo

SW2

123456

ON

a33-9141

Vin - J4 -1 or J4 -4 24Vdc
Io - J4 -2 or J4 -5 4 -20mA output

Fig. 8 -- Space Relative Humidity Sensor Typical Wiring

WIRING
OPENING

C07201

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-MiZert option. To wire in the field:

S J5--8 = 24 VAC source for dry contact
S J5--7 = Signal 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.

S J2--7orJ5--2=24VACforenthalpyswitchpower
S J2--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).

8

J4-1 or J4-4 + 24 VDC Supply Voltage

J4-2 or J4-5 (-) 4 to 20 mA Current Loop Output

to RTU-OPEN

Fig. 9 -- Duct Relative Humidity Sensor Typical Wiring

4-20 VAC GND 0-5V
mA or or
VDC 0-10V

SPAN

Relative Humidity Sensor
(Polarized Male Connector)

ZERO

C10839

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 10.)

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 Low
Voltage Terminal Board (LVTB).

S LVTB -- UNIT SHUTDOWN -- 24v OUT = 24 VAC

source

S LVTB -- 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.

9

Fig. 10 -- Enthalpy Switch and Sensor Wiring

C10821

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. 11 and 12 for
protocol switch settings and address switches. The 3rd
party connection to the RTU--OPEN is through plug J19.
See Fig. 13 for wiring. Refer to the RTU--OPEN 3rd Party
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--Vu OPEN

I-Vu OPEN 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 devices
communicate with a proprietary language called Linkage
on I-Vu OPEN. Linkage is established automatically and
allows the flow of specific data across OPEN devices.
Refer to I-Vu OPEN literature for more information on
I-Vu.

BACnet MS/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.

10

SW3 Protocol Selection

PROTOCOL DS8 DS7 DS6 DS5 DS4 DS3 DS2 DS1
BACnet MS/TP

(Master)
Modbus

(Slave)
N2

(Slave)
LonWorks Unused ON ON OFF ON OFF OFF ON

NOTE:
DS = Dip Switch
BACnet MS/TP SW3 example shown

BAUD RATE DS2 DS1

9600 OFF OFF
19,200 ON OFF
38,400 OFF ON
76,800 ON ON

Unused OFF OFF OFF ON OFF Select Baud Select Baud

Unused OFF OFF ON ON OFF Select Baud Select Baud

Unused OFF OFF OFF ON ON OFF OFF

Baud Rate Selections

Fig. 11 -- RTU--OPEN SW3 Dip Switch Settings

Fig. 12 -- RTU--OPEN Address Switches

C10815

C07166

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 LON--OC. The address switches
(SW1 & SW2) are not used with LonWorks.

Fig. 13 -- Network Wiring

C10816

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Fig. 14 -- LON--OC and LON Network Wiring

C10817

Local Access

BACview6Handheld

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The BACview
connect to the RTU--OPEN to access the control
information, read sensor values, and test the RTU. (See
Fig. 15.) This is an accessory interface that does not come
with the RTU--OPEN controller. You connect the
BACview

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one of the communicating space sensor’s access port.
There are 2 password protected levels in the display (User
and Admin). The user password is defaulted to 0000, but
can be changed. The Admin password is 1111 and cannot
be changed. There is a 10 minute auto logout if a screen is
left idle. See Appendix A for navigation and screen
content.

is a keypad/display interface used to

to the RTU--OPEN’s J12 local access port or

Virtual BACview

Virtual BACview is a freeware computer program that

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functions as the BACview

Handheld. The USB Link
interface (USB--L) is required to connect a computer to
the RTU--OPEN board. The link cable connects a USB
port to the J12 local access port. This program functions
and operates identical to the handheld.

Field Assistant

Field Assistant is a computer program included with the
purchase of the USB Link Tech Kit (USB-TKIT). This is
a field Tech Tool to set-up, service, or download the
RTU-OPEN controller. The link cable connects a USB
port to the J12 local access port. The menu structure is
similar to the BACview, but accessed and functions the
same as I-Vu.

Fig. 15 -- BACview6Handheld Connections

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C07170

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.

Humidi--MiZert Control Wiring

In units equipped with the optional Humidi-MiZer option
there are 2 pink wires loose in the control box used to
control the dehumidification function of the unit. These
pink wires are meant to be ties to a space humidistat or
thermidistat on an electromechanical unit. On
RTU-OPEN equipped units these pink wires must be
connected to J11-7 & 8 to allow the OPEN board to
operate the dehumidification function or the unit.
Disconnect the J11 Phoenix style connector form the
board and use the plug screws to secure the pink wires in
pins 7 and 8, reconnect the plug to the board at J11.

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 low voltage terminal board (LVTB) is a
logical source.

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:

S Outdoor air temperature limits for cooling circuits,

economizer, and heating are ignored.

S Normal compressor time guards and other staging

delays are ignored.

S The 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 at the unit display or
from the network. 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.

NOTE: Service Test mode is password protected when
accessing from the display. Depending on the unit model,
factory--installed options, and field--installed accessories,
some of the Service Test functions may not apply.

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.

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: Compressor 1 is always operated with
Compressor 2 due to outdoor fan control on Compressor

1. Always test Compressor 1 first, and leave it on to test
Compressor 2.

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.

Reversing Valve Test

This test point activates the DO7 relay at J11. These
rooftop units do not use reversing valve control for heat
pumps, therefore this test is not used.

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Dehumidification Test

For units with the factory Reheat option, the
dehumidification 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 dehumidification mode;
dehumidification relay on and the cooling test
(compressor test relays) on puts unit and or individual
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.

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.

Analog Output 2 Test

This test point activates the AO2 0-10vdc analog output at
J22. These rooftops do not use this output, therefore this
test is not used.

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 BACview
menu structure.

Setpoint

Occupied Heating Setpoint -- The heating setpoint the

controller maintains during the occupied period.

Range = 40-90_F

Occupied Cooling Setpoint – The cooling setpoint the
controller maintains during the occupied period.

Range = 55-99_F

Unoccupied Heating Setpoint – The heating setpoint the
controller maintains during the unoccupied period.

Range = 40-90_F

Unoccupied Cooling Setpoint – The cooling setpoint the
controller maintains during the unoccupied period.

Range = 55-99_F

Effective Heating Setpoint – The current setpoint value
heating operation will control to.

Effective Cooling Setpoint – The current setpoint value
cooling operation will control to.

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 hours

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 = 90%

DCV Max Ctrl Setpoint – The difference between indoor
and outdoor CO
ventilation damper position.

Range = 0-9999ppm Default = 650ppm

Power Exhaust Setpoint – When the economizer damper
position opens above this point the power exhaust
operation will begin. When the damper position falls
below this point and 5% lower the power exhaust will
shutdown.

Range = 20-90% Default = 50%

NOTE: This point is only used when Continuous
Occupied Exhaust = NO

level which results in maximum

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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

Unit Start Delay – Refers to the time delay the unit will
wait after power up or when transitioning from
unoccupied to occupied before it pursues any specific
operation.

Range = 0-30 sec Default = 5 sec

Fan Off Delay – Time delay in which the fan will
continue run after being commanded off.

Range = 0-180sec Default = 90sec

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 = 45-70_F Default = 50_F

Maximum Heating SAT – The supply air temperature
must remain below this value to allow heating. There is
5_F plus 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 = 95-150_F Default = 120_F

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