Carrier 48FC Series User guide

1
Controls, Start-- Up, Operation
and Troubleshooting
48/50FC 04---07, 48/50GC 04---06
Single Package Rooftop Units
with SystemVu™ Controls Version 1.X
and Puronr(R---410A) Refrigerant
C150173
IMPORTANT: This literature covers 48/50FC 04--07 and 48/50GC 04--06 models with SystemVu controls version 1.X (factory--installed
option).
TABLE OF CONTENTS
Page
SAFETY CONSIDERATIONS 2.........................
GENERAL 3.........................................
Conventions Used in This Manual 3......................
BASIC CONTROL USAGE 3...........................
SystemVu Control (factory--installed option) 3..............
SystemVu Interface 3.................................
Accessory NavigatortDisplay 4........................
System PilottandTouchPilottDevices 5................
CCN Tables and Display 5.............................
START--UP 6.........................................
Unit Preparation 6....................................
Refrigerant Service Ports 6.............................
Crankcase Heater 6...................................
Compressor Rotation 6................................
Power Supply 6.....................................
Internal Wiring 6.....................................
Evaporator Fan 6....................................
Condenser Fans and Motors 6...........................
Return--Air Filters 8..................................
Outdoor--Air Inlet Screens 8............................
Accessory Installation 8...............................
Gas Heat (48FC and 48GC) 8...........................
CONTROLS QUICK SET--UP 8.........................
Control Set Point and Confirmation Log 8.................
Initial Startup 8......................................
Thermostat Control 9.................................
Space Temperature Sensor Control -- Direct Wired
(T--55 or T--56 or T--59) 9.............................
Space Humidistat Control 9............................
Space Relative Humidity Sensor Control 9.................
CCN Communication 9...............................
CCN Linkage Control 9...............................

2
System Pilott-- Communication Space Sensor 9...........
Accessories 9.......................................
Programming Operating Schedules 10....................
SERVICE TEST 10....................................
Independent Outputs 10...............................
Fan Test 10.........................................
Cooling Test 11.....................................
Heating Test 11......................................
Automatic Test 11....................................
THIRD PARTY CONTROL 12..........................
Cooling/Heating Control 12............................
Dehumidification Control 12...........................
Remote Occupancy 12................................
Remote Shutdown 12.................................
Alarm Output 12.....................................
Economizer Damper Control 12.........................
CONTROLS OPERATION 12...........................
Display Configuration 12..............................
Unit Configuration 12.................................
General Operation 13.................................
Demand Determination 13.............................
Occupancy Determination 15...........................
Indoor Fan Operation 16...............................
Cooling Operation 16.................................
Optional Humidi--MiZerRDehumidification System 17......
Indoor Fan Based Dehumidification 21...................
Heating Operation 21.................................
Supply Air Tempering 22..............................
Two Position Damper Operation 22......................
Economizer Operation 22..............................
Power Exhaust 24....................................
Indoor Air Quality (IAQ) 25............................
Pre--occupancy Purge 26...............................
Temperature Compensated Start 26.......................
Linkage 26.........................................
Carrier Comfort NetworkR(CCN) Operation 26............
BACnet Network Operation 26.........................
Alarm Handling 27...................................
TROUBLESHOOTING 27..............................
Complete Unit Stoppage 27............................
Restart Procedure 27..................................
Faults and Alerts 27..................................
Control Module Communication 34......................
Communication Failures 34............................
Cooling Troubleshooting 35............................
Humidi--MiZer System Troubleshooting 36................
Economizer Troubleshooting 37.........................
Heating Troubleshooting 38............................
Phase Protection 41..................................
Thermistor Troubleshooting 41.........................
Sensor Trim 41......................................
Transducer Troubleshooting 41.........................
MAJOR SYSTEM COMPONENTS 46....................
General 46.........................................
Main Base Board (MBB) 54............................
Integrated Gas Control (IGC) Board 56...................
Protective Devices 57.................................
Space Mounted Sensors 57.............................
Carrier Comfort NetworkR(CCN) Interface 59.............
APPENDIX A: SystemVutController Display 61...........
APPENDIX B: SystemVu Controller Text Point Reference 83...
APPENDIX C: NavigatortDisplay 84....................
APPENDIX D: SystemVu Controller CCN Tables 95..........
APPENDIX E: BACnet Points List 119....................
CONTROL SET POINT AND CONFIGURATION LOG 132...
UNIT START--UP CHECKLIST 143......................
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. Use quenching cloth for unbrazing
operations. Have fire extinguishers available for all brazing operations.
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 cause personal injury
or death.
Before performing service or maintenance operations on
unit, turn off main power switch to unit and install lockout
tag. Ensure electrical service to rooftop unit agrees with
voltage and amperage listed on the unit rating plate.
!WARNING

3
UNIT DAMAGE HAZARD
Failure to follow this caution may cause equipment
damage.
This unit uses a microprocessor--based electronic control
system. Do not use jumpers or other tools to short out
components or to bypass or otherwise depart from
recommended procedures. Any short--to--ground of the
control board or accompanying wiring may destroy the
electronic modules or electrical components.
CAUTION
!
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Improper installation, adjustment, alteration, service, or
maintenance can cause property damage, personal injury, or
loss of life. Refer to the User’s Information Manual
provided with this unit for more details.
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance. What
to do if you smell gas:
1. DO NOT try to light any appliance.
2. DO NOT touch any electrical switch, or use any phone in
your building.
3. IMMEDIATELY call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
4. If you cannot reach your gas supplier, call the fire
department.
!WARNING
GENERAL
This publication contains Start--Up, Controls, Operation, Service,
and Troubleshooting information for the 48/50FC and 48/50GC
rooftop units equipped with the factory--installed optional
SystemVutcontrols (version 1.X or higher) and use Puronr
(R--410A) refrigerant. The specific base unit installation
instructions, service manual and/or wiring label diagram may also
be required in conjunction with this book as a guide to a specific
unit on the roof. All units in Table 1 are Staged Air Volume
(SAVt) units that allow for stand--alone or network operation.
Table 1 – Rooftop Units
MODEL SIZE NOMINAL TONS
48/50FC
04 3
05 4
06 5
07 6
48/50GC
04 3
05 4
06 5
Conventions Used in This Manual
The following conventions for discussing configuration points for
the local display (SystemVu controller or Navigatortaccessory)
will be used in this manual.
Menu paths will be written with the main menu name first, then
any menus or sub menus, each separated by an arrow symbol ()
and will also be shown in bold and italics. As an example, the
General sub menu which is located in the Setting main menu under
Unit Configuration menu would be written as SETTINGS
UNIT CONFIGURATIONSGENERAL.
This path name will show the user how to navigate through the
local display to reach the desired menu. The user scrolls through
the Menus using the up and down keys. The arrow symbol in the
path name represents pressing ENTER to move into the next level
of the menu structure.
Point names are referenced in in parentheses and bold and italics as
would be shown on the local display.
CCN point names are also referenced for users configuring the
unit with CCN software instead of the local display. See
Appendix A at the end of this manual.
BASIC CONTROL USAGE
SystemVu Control (factory--installed option)
The SystemVu control is a comprehensive unit-management
system. The control system is easy to access, configure, diagnose
and troubleshoot.
The SystemVu control system is fully communicating and
cable-ready for connection to the Carrier Comfort Network
(CCN), Carrier i--Vu, and Third Party BACnet* building
management systems. The control provides high-speed
communications for remote monitoring via the Internet. Multiple
units can be linked together (and to other Direct Digital Control
(DDC) equipped units) using a 3-wire communication bus.
The SystemVu control system is easy to access through the use of a
integrated display module. A computer is not required for start-up.
Access to control menus is simplified by the ability to quickly
select from 7 main menu items. An expanded readout provides
detailed explanations of control information. Only six buttons are
required to maneuver through the entire controls menu. The
display readout is designed to be visible even in bright sunlight.
BACK ENTER MENU
RUN
ALERT
FAULT
System u
TESTTEST
C14319
Fig. 1 -- SystemVu Interface
SystemVu Interface
This integrated device is the keypad interface used to access the
control information, read sensor values, and test the unit. The
interface is located in the main control box and is standard on all
units. The interface is a 6--key, 4x30 character, LCD (liquid--crystal
display) display module. The interface also contains Status LEDs.
(See Fig. 1.) The interface is easy to operate using 6 buttons and
themainmenustructuresshowninFig.2.
Through the SystemVu interface, the user can access all of the
inputs and outputs to check on their values and status, configure
operating parameters, and evaluate the current decision status for
operating modes. The control also includes an alarm history which
can be accessed from the display. The user can access a built--in test
routine that can be used at start--up commissioning and
troubleshooting.
* BACnet is a registered trademark of ASHRAE (American Society of
Heating, Refrigerating and Air ---Conditioning Engineers).

4
a48---10366
Fig. 2 -- SystemVut-- Main Menu Structures
SystemVu Interface Operation
Units are shipped from the factory with the SystemVu interface
FIOP, located in the main control box. (See Fig. 1.) In addition, the
interface has up and down arrow keys, BACK, ENTER, MENU,
and TEST keys. These keys are used to navigate through the
different levels of the menu structure. All discussions and examples
in this document will be based on the SystemVu display except in
the Navigatortdisplay section. See the Accessory Navigator
Display section for further details and Table 2 for the Navigator
menu structure and usage.
The six keys are used to navigate through the display structure,
which is organized in a tiered menu structure. If the buttons have
not been used for a period, the display will default to a standby
screen intended to provide a quick overall look at the system. To
show the top--level display, press any key first to turn the display
backlight on, and then press the MENU key. Then use the up and
down arrow keys to scroll through the top--level menus. These are
showninFig.2andlistedinAppendixA.
When a specific menu or sub--menu is located, push the ENTER
key to enter the menu. Depending on the menu, there may be
additional tiers. Continue to use the up and down keys and the
ENTER key until the desired display item is found. At any time,
the user can move back a menu level by pressing the BACK key.
Once an item has been selected the display will flash showing the
item, followed by the item value and then followed by the item
units (if any). Pressing the TEST button at any time will jump the
display to the test menu. Pressing the MENU button any time will
jump the display to the main menu.
Items in the Configuration and Service Test menus are password
protected. The display will prompt the enter password screen when
required. Use the ENTER, BACK, and arrow keys to enter the four
digits of the password. The default user password is 1111.
Pressing the BACK and ENTER keys simultaneously will show an
expanded text description screen on the display indicating the full
meaning of each display point. To put the screen in standby, hold
down the BACK key for 5 seconds.
Some points can be forced from the SystemVutinterface. To force a
variable, follow the same process as editing a configuration
parameter. A forced variable, regardless where the force has come
from will be displayed with a lower case “f” following its value.
For example, if ECON CMD POSITION is forced, the display
shows “80%f”, where the “f” is to signify a force on the point.
Remove the force by selecting the point that is forced with the key
ENTER and then pressing the up and down arrow keys
simultaneously. Pressing ENTER and BACK on a forced item will
display the expanded description for that item including the force
level that is currently applied. Depending on the type of unit
(48FC,GC or 50FC,GC), factory--installed options and
field--installed accessories, some of the items in the various menus
may not apply.
Accessory NavigatortDisplay
The accessory hand-held Navigator display can be used with the
48/50FG, GC units. (See Fig. 3.) The Navigator display is plugged
into the LEN (local equipment network) port on either the
SystemVu display or the Main Base Board (MBB).
Navigator Display Operation
The Navigator display has up and down arrow keys, an ESCAPE
key and an ENTER key. These keys are used to navigate through
the different levels of the display structure.
The four keys are used to navigate through the display structure,
which is organized in a tiered mode structure. If the buttons have
not been used for a period, the display will default to the AUTO
VIEW display category as shown under the RUN STATUS
category. To show the top-level display, press the ESCAPE key
until a blank display is shown. Then use the up and down arrow
keys to scroll through the top-level categories. These are listed in
Appendix C and will be indicated on the Navigator display by the
LED next to each mode listed on the face of the display.
Run Status
Service Test
Temperatures
Pressures
Setpoints
Inputs
Outputs
Configuration
Time Clock
Operating Modes
Alarms
ENTER
ESC
MODE
Alarm Status
TIME
EWT
LWT
SETP
12.58
54.6°F
44.1°F
44.0°F
NAVIGATOR
ComfortLink
C06321
Fig. 3 -- Accessory Navigator Display
When a specific mode or sub-mode is located, push the ENTER key
to enter the mode. Depending on the mode, there may be additional
tiers. Continue to use the up and down keys and the ENTER keys
until the desired display item is found. At any time, the user can move
back a mode level by pressing the ESCAPE key. Once an item has
been selected the display will flash showing the item, followed by the
item value and then followed by the item units (if any).
Items in the Configuration and Service Test modes are password
protected. The display will flash PASS and WORD when required.
Use the ENTER and arrow keys to enter the four digits of the
password. The default password is 1111.

5
Table 2 – Navigator Mode and Menu Display Structure
RUN
STATUS
SERVICE
TEST TEMPERATURES PRESSURES SET- POINTS INPUTS OUTPUTS CONFIGURATION TIMECLOCK OPERATING MODES ALARMS
Auto View of
Run Status
(VIEW)

Service Test
Mode
(TEST)

Thermostat
Inputs
(STAT)

General
Outputs
(GEN)

General Unit
Config
(GEN)

Time of Day
(TIME)

Curr Active
Alarm
(CURR)

Cooling
Status
(COOL)

Test Independent
Outputs
(INDP)

Switch
Inputs
(SW)

Cooling
Outputs
(COOL)

Indoor Fan
Config
(I.FAN)

Month, Date
Day and Year
(DATE)

History
(HIST)

Heating
Status
(HEAT)

Te s t F a n s
(FANS)

Analog
Inputs
(AIS)

Heating
Outputs
(HEAT)
Economizer
Config
(ECON)

Daylight
Savings
Config
(DST)

Reset All
Current
Alarms
(R.CUR)

Ventilation
Status
(VENT)

Test Cooling
(COOL)

General
Inputs
(GEN)
Building Net
Config
(NET)

Schedules
Adjust
(SCHD)

Alarm Reset
History
(R.HIS)
Assigned I/O
Channels
(A.IO)

Te s t H e a t i n g
(HEAT)
User Display
Config
(DISP)
Holiday
Adjustment
(HLDY)
Versions
(VERS)
Pressing the ESC and ENTER keys simultaneously will display an
expanded text description across the display indicating the full
meaning of each display point. Pressing the ESCAPE and ENTER
keys when the display is blank (MODE LED level) will return the
display to its default menu of rotating AUTO VIEW display items.
In addition, the password will need to be entered again before
changes can be made.
Changing item values or testing outputs is accomplished in the
same manner. Locate and display the desired item. If the display is
in rotating auto-view, press the ENTER key to stop the display at
the desired item. Press the ENTER key again so that the item value
flashes. Use the arrow keys to change the value of state of an item
and press the ENTER key to accept it. Press the ESCAPE key and
the item, value or units display will resume. Repeat the process as
required for other items.
There are some points that can be forced from the Navigator
display. If the user needs to force a variable, follow the same
process as when editing a configuration parameter. A forced
variable, regardless where the force has come from will be
displayed with a blinking “f” on a Navigator display following its
value. For example, if economizer commanded position (EC.CP) is
forced, the Navigatortdisplay shows “80f”, where the “f” is
blinking to signify a force on the point. Remove the force by
selecting the point that is forced with the key ENTER and then
pressing the up and down arrow keys simultaneously.
Depending on the type of unit (48FC,GC or 50FC,GC),
factory-installed options and field-installed accessories, some of the
items in the various Mode categories may not apply.
See Table 2 and Appendix C for full Navigator display menu
layout.
System Pilottand Touch PilottDevices
The System Pilot device (33PILOT-01) and Touch Pilot device
(33CNTPILOT) can be used as CCN communication
user--interfaces. These devices can be put on the CCN bus and
addressed to communicate with any other device on the network.
Unlike the SystemVutdisplay and Navigator display, these pilots
read the unit’s CCN tables and its CCN points can be monitored,
forced, or configured. The Pilot devices can be used to install and
commission a 3Vtzoning system, linkage compatible air source,
universal controller, and all other devices operating on the Carrier
communicating network.
Additionally, the System Pilot device can serve as a wall-mounted
temperature sensor for space temperature measurement. Occupants
can use the System Pilot device to change set points. See Fig. 4 for
System Pilot device details.
CCN Tables and Display
In addition to the unit--mounted SystemVutdisplay, the user can
also access the same information through the CCN tables by using
the service tool or other CCN programs/devices. The variable
names used for the CCN tables and the SystemVu display menus
may be different and more items may be displayed in the CCN
tables. Details on the CCN tables are included in Appendix D.
SCROLL +
-
NAVIGATE/
EXIT
MODIFY
/
SELECT
PAGE
C06322
Fig. 4 -- System PilottUser Interface
Force Hierarchy
There is a hierarchy in SystemVu controls with regards to forcing a
point. Programs and devices write a force at different priority
levels. A higher level (smaller number, 1 being the highest) will
override a lower level force. The SystemVu controller uses a
Control Force at level 7. The Navigatortdevice writes a Service
Force which is level 3. System Pilottand Touch Pilottdevices
write Supervisor Forces at level 4. Network programs can be set to
write different level priority forces.
NOTE: In the case of a control power reset, any force in effect at
the time of power reset will be cleared.
IMPORTANT: All further discussions and examples in this
document will be based on the SystemVutcontroller.

6
START-UP
IMPORTANT: Do not attempt to start unit, even momentarily,
until all items on the Start--Up Checklist (see page 143) and the
following steps have been read/completed.
Unit Preparation
Check that unit has been installed in accordance with these
installation instructions and all applicable codes.
Refrigerant Service Ports
The refrigerant system has a total of 3 Schrader-type service gauge
ports per circuit. One port is located on the suction line, one on the
compressor discharge line, and one on the liquid line. Be sure that
caps on the ports are tight.
Crankcase Heater
The compressor is equipped with a crankcase heater. There is a control
function used to turn the crankcase heaters on and off when the
compressor is not running. This is a configurable value for which the
factory default value is set to 65_F. If the ambient is above the selected
value the control will prevent the crankcase heater from turning on.
IMPORTANT: Unit power must be on for 24 hours prior to
start--up to allow the crankcase heater to run. Otherwise, damage to
the compressor may result.
Compressor Rotation
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit damage.
Improper wiring will cause compressor stoppage and alarm.
Correct wiring by switching leads as indicated below.
CAUTION
!
On 3-phase units, it is important to be certain the compressors are
rotating in the proper direction. To determine whether or not
compressors are rotating in the proper direction, use a phase-rotation
meter on the unit input power to check for L1-L2-L3 or clockwise
rotation or use the Service Test mode to energize a compressor. If the
compressor is rotating in the wrong direction, the controls will stop the
compressor and display alarm for “Circuit A Reverse Rotation”.
NOTE: Indoor or outdoor fan rotation direction may not indicate
proper input power phase sequence, as some 3-phase units use
single-phase fan motors.
To correct the wrong compressor rotation direction, perform the
following procedure:
1. Turn off power to the unit and lock out the power.
2. Switch any two of the incoming unit power leads.
3. Turn on power to the unit.
4. Verify corrected compressor rotation.
Power Supply
All 208/230-v units are factory wired for 230-v power supply. If
the 208/230-v unit is to be connected to a 208-v power supply, the
transformers must be rewired by moving the wire from the
230-volt connection and moving to the 200-volt terminal on the
primary side of the transformer. Refer to unit label diagram for
additional information.
Internal Wiring
Check all electrical connections in unit control boxes; tighten as
required.
Evaporator Fan
The Evaporator fan does not need to be checked for rotation as it
only operates in one direction. Refer to the unit product data for
full Fan Performance tables and physical data. The specific unit’s
fan performance table is printed and adhered to the control box
high voltage cover. See Fig. 5 for an example fan performance
table.
Use the job specifications and unit fan performance table to determine
the operating mode specific fan speeds. The following instructions are
included in the unit installation instructions. When adjusting the
Heating Fan Speed and High Cooling Fan Speed, ensure that the
CFM is not lower than the minimum CFM allowed in the product
data.
1. Check the job specifications for the CFM (cubic feet per
minute) and ESP (external static pressure) required.
2. Using the chart on the Fan Speed Set Up labels (see Fig. 5),
calculate the RPM from the CFM and ESP for the base unit
plus any field accessories (as listed on the label).
NOTE: The Fan Speed Set Up labels are located on the High
Voltage cover in the Control Box.
3. Press any key on the SystemVu interface to activate the
display backlight and then press the MENU key.
4. Using the UP and DOWN arrow keys highlight SETTINGS
and then press ENTER.
5. Use the DOWN arrow key highlight the UNIT
CONFIGURATIONS menu then press ENTER.
6. Highlight UNIT CONFIGURATIONS then press ENTER.
7. Highlight INDOOR FAN and then press ENTER.
8. Refer to the job specifications to set the following,
determining the values per the RPM Calculator label
(Figure 5). Use the UP and DOWN arrow keys and the
BACK key to set the values. Press ENTER after setting
each value to continue to the next selection.
SIDF VENT SPD
SIDF HEAT SPD
SIDF LOW COOL SPD
SIDF HIGH SPD
SIDF FREE COOL SPD
Service test mode can also be used to temporarily operate the
Evaporator Fan with a percentage (0--100%) command. The fan
test menu will show the converted RPM from the percentage being
commanded. Refer to the Service test section for more details.
Adjust the IDF Maximum Fan Speed (IDF MAX SPEED) to
restrict higher fan speeds as needed for sensitive applications.
IMPORTANT: The IDF Maximum Fan Speed (IDF MAX
SPEED) RPM must not produce a supply CFM that is lower than
the minimum CFM allowed in the product data for heating and
cooling. The IDF Maximum Fan Speed (IDF MAX SPEED) must
also be greater than or equal to the highest operating mode speed
setting.
Condenser Fans and Motors
Condenser fans and motors are factory set.

7
Field Accessories:
2500
Economizer
ESP in. wg
RPM Calculator
CFM
0.2
1301
1381
1463
1548
1633
1720
1808
1897
1987
1500
1625
1750
1875
2000
2125
2250
2375
66
80
107
0.4
1477
1544
1615
1688
1764
1842
1921
2003
2068
66
0.6
1639
1699
1763
1828
1897
1967
2040
2115
2191
0.8
1788
1843
1902
1962
2025
2090
2157
2227
2298
66
1.0
1925
1976
2031
2087
2146
2208
2271
2336
66
1.2
2054
2101
2152
2206
2262
2320
2380
66
1.4
2174
2220
2268
2318
2372
66
1.6 1.8 2.0
2289
2332
2378
66 66
80 80 80 80 80 80 80
107 107 107 107 107 107 107
1 Stage E Heat
2 Stage E Heat
UNIT MODEL NUMBER
a50---10219
Fig. 5 -- Example of Fan Speed Set Up Labels

8
INDOOR
BLOWER
ACCESS
PANEL
CONTROL BOX
AND GAS SECTION
ACCESS PANEL INDOOR COIL
ACCESS PANEL
FILTER
ACCESS PANEL
UNIT BACKUNIT FRONT
a48---9937
Fig. 6 -- Panel and Filter Locations
Return--Air Filters
Check that correct filters are installed in filter tracks (see Physical
Data table in unit Product Data). Do not operate unit without
return-air filters. Determine the filter change run time (DIRTY
FILTER TIME) to be set in the quick setup configurations menu.
Outdoor--Air Inlet Screens
Outdoor-air inlet screens must be in place before operating unit.
Accessory Installation
Check to make sure that all accessories including space thermostats
and sensors have been installed and wired as required by the
instructions and unit wiring diagrams.
Gas Heat (48FC and 48GC)
Inspect the gas heat section of the unit. Verify the number of
burners match the number of heat exchanger openings and the
burner assembly is properly aligned. If the orifices were changed
out for elevation or Liquid Propane purposes, verify proper
installation. Visually inspect other components in heat section.
Verify gas pressures before turning on heat as follows:
1. Close the field-supplied manual gas shut off valve, located
external to the unit.
2. Connect a pressure gauge to the supply gas pressure tap,
located on the field-supplied manual gas shut off valve (see
Fig. 7).
MANUAL GAS SHUT OFF VALVE
(FIELD SUPPLIED)
SUPPLY GAS
PRESSURE TAP
(1/8˝ NPT PLUG)
GAS
SUPPL
Y
SEDIMENT TRAP
UNION
TO
UNIT
a48---9382
Fig. 7 -- Field Gas Piping
3. Connect a pressure gauge to the manifold pressure tap on
the burner assembly located inside the unit.
4. Open the field-supplied manual gas shut off valve. Enter
Service Test mode by setting TEST MODE to “ON” using the
SystemVutcontroller interface. Use the Service Test feature
to set HEAT 1 TEST to ON (first stage of heat) using the
SystemVu controller interface.
5. After the unit has run for several minutes, verify the supply
gas pressure is adequate per the base unit installation in-
structions. If not, adjust accordingly.
NOTE: Supply gas pressure must not exceed 13.0--in. wg.
6. Set HEAT 1 TEST to OFF using the SystemVu controller
interface.
7. Exit Service Test mode by setting TEST MODE to “OFF”
using the SystemVu controller interface.
CONTROLS QUICK SET--UP
The following information will provide a quick guide to setting up
and configuring the 48/50FC and 48/50GC series units with
SystemVu controls. Unit controls are pre-configured at the factory for
factory-installed options. Field-installed accessories will require
configuration at start-up. Initial System Startup is recommended for
initial start--up. Additionally, specific job requirements may require
changes to default configuration values. See Appendix A and other
sections of these instructions for more details. Refer to the Major
System Components or accessory installation instructions for specific
wiring detail.
Control Set Point and Configuration Log
During start up, accessory installation, and equipment service set
points and/or configuration changes might have to be made. When
setting set points or configuration settings, documentation is
recommend. The Control Set Point and Configuration Log starting
on page 132 should be filled out and left with the unit at all times,
a copy should also be provided to the equipment owner. A USB
jump drive can be used to back up the unit’s configurations. Refer
to the USB Operation section for details.
Initial Startup
Initial Startup refers to the first time this particular unit has a startup
performed. The SystemVu controller will continually display the
Initial Startup prompt until it is completed. To complete the initial
startup you must complete the Quick Setup, Network Setup, and
the System Auto Test.

9
Quick Setup
This a list of common adjusted configurations set during startup.
These are common accessories, and control means. Set the list in
Table 3. After setting these per the specific unit set the QUICK
SET CHKLIST point to done.
Table 3 – Quick Setup Menu Items
SystemVu™ Display Expanded Name Range Default
QUICK SETUP CONFIG QUICK SETUP
CONFIG MENU
TIME Clock Hour and Minute HH:MM
DATE Current Date MM/DD/YYYY
STARTUP DELAY Unit Startup Delay 10 to 600 30
UNIT CONTROL TYPE Unit Control Type 0=TSTAT,
1=SPACE SEN,
2=RAT SEN
0
THERMOSTAT TYPE Thermostat Hardware
Type
0=CONV 2C2H,
1=DIGI 2C2H,
2=CONV 3C2H,
3=DIGI 3C2H
2
DIRTY FILTER TIME Change Filter Timer 0to9999 600
HEATINGSTAGQTY Number of Heating
Stages
1to2 2*
VENT METHOD Ventilation Method 0=NONE
1=ECON
2=2POS DMPR
3=ERV
4=ECON ERV
0*
FREECOOL MAX OAT Free Cooling Max OAT 0to90 65
FIRE SHUTDOWN SW Fire Shutdown Switch 0=No Switch,
1=N/Open
2=N/Close
0*
QUICK SET CHKLIST QUICK SETUP
CHECKLIST
0=Undone,
1=View,
2=Done
0
* These defaults change based on the Unit model number.
Network Setup
This is a shortcut to the Network Settings submenu. In this sub
menu are the specific network settings required to get the network
piece up and running. After setting these per the specific unit set
the NETWORK CHKLIST point to done.
System Auto Test
Turning this to Start will run enable test mode and execute the System
Auto Test. After the auto test has completed, set this to done.
Thermostat Control
Wire accessory thermostat to the corresponding R, Y1, Y2, W1,
W2, and G terminals on the Main Base board.
The Unit Control Type configuration, (UNIT CONTROL TYPE)
default value is for thermostat (0) so there is no need to configure
this item.
The Thermostat Hardware Type, (THERMOSTAT TYPE) selects
the unit response to the thermostat inputs above.
NOTE: May not be compatible with heat anticipator thermostats.
Space Temperature Sensor Control -- Direct Wired
(T--55 or T--56 or T--59)
Wire accessory space temperature sensor(s) to the T-55 terminals
on the field connection terminal board located at the unit control
box. Refer to Space Mounted Sensors section (page 57) for
additional information.
The Unit Control Type configuration, (UNIT CONTROL TYPE)
must be set to Space Sensor (1).
Space Humidistat Control
For units with factory installed Humidi--MiZerRsystem option, the
humidistat input is defaulted for use on the Y3 thermostat input
screw terminal as a normally open switch. This can be changed
with the Humidistat Switch Channel configuration (HUMSTAT
CHANNEL) and the Humidistat switch type configuration
(HUMSTAT SW TYPE).
Space Relative Humidity Sensor Control
For units with factory installed Humidi--MiZer system option, a
Relative Humidity (RH) sensor input can be used in addition to or
in place of the Humidistat switch. This can be done by wiring into
one of the configurable analog inputs and setting the Space
Relative Humidity sensor channel (SPRH SENSOR CHAN) to the
input channel selected. The most field accessible input channel is
AI06 located at TB5--5 on the MBB (Main Base board).
CCN Communication
First configure the building protocol SETTINGS NETWORK
SETTINGS BAS PROTOCOL to CCN (default is 0 = NONE).
Configure the following under the CCN menu (SETTINGS 
NETWORK SETTINGS CCN).
CCN ELEMENT # -- D e f a u l t i s 1
BUS NUMBER -- D e f a u l t i s 0
CCN BAUDRATE -- Default is 2 = 38400
CCN Linkage Control
The CCN communication must be properly configured for the
units and all other devices. Linkage configuration is automatically
done by the supervisory CCN Linkage device.
The unit control type configuration, (UNIT CONTROL TYPE)
must be set to space sensor (1).
The factory location of the SAT sensor will read accurately for
heating and cooling for proper operation with linkage applications,
therefore the SAT heating mode sensing configuration (SAT
DURING HEAT?) is enabled from the factory. If a more accurate
SAT reading is need, the sensor can be re--located into the duct and
no configuration adjustment needed.
System Pilott-- Communication Space Sensor
Install the System Pilot device and connect the CCN communication
bus from it to the unit’s CCN connection on TB4 -- BAS connector of
the Main Base Board (MBB). Configure the unit’s CCN
communication element number, bus number, and baud rate. Refer to
the System Pilot’s installation instructions for configuring it to be used
as a space temperature and attaching it to a unit.
Accessories
Below are quick configuration settings for field--installed
accessories. When factory--installed as options the points will
already be configured. See the Space Mounted Sensors section
(page 57), third party control, control connection tables, and CCN
or Display parameter tables for any accessories not mentioned
below and refer to installation manual of the accessory.
Economizer
When an economizer is field--installed, the unit must be configured
for it by setting SETTINGSUNIT CONFIGURATIONS 
ECONOMIZER VENT METHOD to ECON. The default
settings for the other economizer configurations should be
satisfactory. If they need to be changed, additional information
about these configuration settings can be found in the Economizer
section.
Power Exhaust
When power exhaust is field--installed, the unit must be
configured for it by setting SETTINGSUNIT
CONFIGURATIONSECONOMIZER POWER EXHAUST
CONFIGS PE1 RELAY CHANNEL to the channel the
accessory was wired into. The default settings for the other power
exhaust configurations should be satisfactory. If they need to be
changed, additional information about these configurations can be
found in the Power Exhaust section.
Electric Heat
When electric heat is field--installed, the number of electric heat stages
must be configured by setting SETTINGS UNIT
CONFIGURATIONS HEATING HEATING STAGE QTY
per the installed heater.

10
Fire Shutdown
When Fire Shutdown or Smoke Detector sensors are
field--installed, the unit must be configured for it by setting
SETTINGS UNIT CONFIGURATIONS SWITCH INPUTS
CONFIGS FIRE SHUTDOWN SW to normally open (0) or
normally closed (1).
Outdoor Enthalpy
When an Outdoor Enthalpy sensor is field--installed, the unit must
be configured for it by setting SETTINGS UNIT
CONFIGURATIONS ANALOG INPUTS CONFIGS OARH
SENSOR CHAN to the channel number the sensor was wired into.
IAQ Sensor
When a CO2sensor is field--installed, the unit must be
configured for it by setting SETTINGS UNIT
CONFIGURATIONS ANALOG INPUT CONFIGS IAQ
SENSOR CHAN selects the unit response to this input. Default
conversion to 0 to 2000 ppm.
OAQ Sensor
When an Outdoor Air Quality sensor is field--installed, the unit
must be configured for it by setting SETTINGS UNIT
CONFIGURATIONS ANALOG INPUT CONFIGS OAQ
SENSOR CHAN. Default conversion to 0 to 2000 ppm.
Filter Status
When a Filter Status Switch is field--installed, the unit must be
configured by setting the input channel it is wired to and normal state.
SETTINGSUNIT CONFIGURATIONSSWITCH INPUT
CONFIGSFILTER SW CHANNEL and FILTER SW TYPE.
Phase Monitor
When a phase monitor is field--installed, the unit must be
configured by setting the input channel it is wired to and normal
state SETTINGUNIT CONFIGURATIONSSWITCH INPUTS
CONFIGSPHASE MON CHANNEL and PHASE MON SW
TYPE.
Two Position Damper
When a Two Position damper is field--installed, the unit must be
configured by setting the output channel it is wired to.
SETTINGS UNIT CONFIGURATION GENERAL 2POS/
ERV CHANNEL.
Programming Operating Schedules
When the building automation system you have the SystemVut
controller configured for (BAS Protocol Select) is None (0) or
CCN (1) the SystemVu controller can follow a standard CCN
occupancy table. The occupancy can be modified from any CCN
tool or from the local display.
OCCUPANCY SCHEDULE — For flexibility of scheduling, the
occupancy programming is broken into eight separate periods. For
each period the schedule contains the following fields: Day of
Week, Occupied From, and Occupied To.
DAY OF WEEK — The day of week configuration consists of
eight fields corresponding to the seven days of the week and a
holiday field in the following order: Monday, Tuesday,
Wednesday, Thursday, Friday, Saturday, Sunday, and Holiday. If a
1 is configured in the corresponding place for a certain day of the
week, the related “Occupied from” and “Occupied to” times for
that period will take effect on that day of the week. If a 1 is placed
in the holiday field, the related times will take effect on a day
configured as a holiday. A zero means the schedule period will not
apply to that day.
Day of week: Range 0 or 1
Default Values 0 for all of the periods.
OCCUPIED FROM — This field is used to configure the hour and
minute, in 24 hour clock, that the mode for the controller will
switchtooccupied.
Occupied From: Units Hours:Minutes
Range 00:00 to 24:00
(Minutes 00 to 59)
Default Value 00:00
OCCUPIED TO — This field is used to configure the hour and
minute, in 24 hour clock, that the mode for the controller switches
from occupied to unoccupied.
Occupied To: Units Hours:Minutes
Range 00:00 to 24:00
(Minutes 00 to 59)
Default Value 00:00
When the building automation system configured to (BAS
PROTOCOL) is BACnet, the occupancy and holiday information
will be reset to defaults in preparation for receiving a BACnet
occupancy object. While participating on a BACnet network these
configurations cannot be changed at the local interface or with
CCN tools. All scheduling is done from the BACnet interface
designated to provide schedules.
SERVICE TEST
The Service Test function can be used to verify proper operation of
compressors, heating stages, indoor fan, outdoor fans,
Humidi--MiZerRsystem operation, power exhaust fans, economizer,
crankcase heaters, and the alarm relay. Use of Service Test is
recommended at initial system start up and during troubleshooting.
(See Table 4 for point details)
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
reduced to one minute or less.
SCircuit strike out time is reduced to 1 minute instead of 15 minutes.
SIt may take up to 30 seconds to actually enter test mode after
activating the command.
Press the TEST button on the SystemVutinterface anytime to
access the Test menu. Service Test mode can only be turned
ON/OFF at the unit display. Once turned ON, other entries may be
made with the display or through CCN. To turn Service Test mode
on, change the value of TEST MODE to ON. To turn service test
mode off, change the value of TEST MODE to OFF. Service Test
mode will be automatically turned off based on keypad inactivity
and the Service Mode Test Time out (TEST MODE TIMEOUT).
NOTE: Service Test mode may be password protected. Refer to
Basic Control Usage section for more information. Depending on
the unit model, factory--installed options, and field--installed
accessories, some of the Service Test functions may not apply.
Independent Outputs
The INDEPENDENTS submenu is used to change output status
for the economizer, Humidi--MiZer system valves, power exhaust
stages, crankcase heaters, the alarm relay, as well as perform a
compressor bump test. These independent outputs can operate
simultaneously with other Service Test modes. All outputs return to
normal operation when Service Test is turned off. The compressor
bump tests cannot be run while running cooling tests and will
automatically turn off after one minute.
Fan Test
The FAN TESTS submenu is used to setup or test speeds for the
indoor fan. Use the IDF SPEED TEST point to control the indoor
fan speed in terms of %, and use the CONVERTED IDF RPM
point as feedback to help set the fan speed settings in terms of
RPM. The indoor fan transition type point inform the test routine
how to handle the fans while running the cooling or heating tests.
Automatic will automatically transition the fans as the cooling or
heating tests change. While the Manual transition will only run the
fans as set by the test points.

11
Cooling Test
The COOL submenu is used to change output status for the
individual compressors and Humidi--MiZer system operation. The
HEAT submenu service test outputs are reset to OFF for the
cooling service test. Indoor fans and outdoor fans are controlled
normally to maintain proper unit operation when set for automatic
transition. The IDF SPEED TEST and ALL ODFSPD TEST can
be changed as needed for testing. These fans points show the
requested speed not actual speed. All normal cooling faults and
alerts are functional.
Heating Test
The HEAT submenu is used to change output status for the
individual heat stages, gas or electric. The COOL service test
outputs are reset to OFF for the heating service test. Indoor fan is
controlled normally to maintain proper unit operation when set for
automatic transition. The IDF SPEED TEST can be changed as
needed for testing and shows the requested speed not actual speed.
All normal heating faults and alerts are functional.
NOTE: When the IGC fan on command (IGC FAN REQUEST)
is active the fan may run when not expected.
Table 4 – Test Mode Unit Test Directory
Display Menu/Sub menu/Name Expanded Name Values
UNIT TESTS Unit Tests Menu
TEST MODE ServiceTestModeEnable Off/On
SERVICE TEST Service Test Menu
INDEPENDENTS INDEPENDENT TEST MENU
ECON POS TEST Economizer Position Test 0 to 100
BUMP COMP A1 TEST Compressor Bump A1 Test Off/On
RH DIS VALVE TEST Rht Dischg Valve Rly Tst Off/On
RH LIQ VALVE TEST Reheat Liq Valv Rly Test Off/On
CL LIQ VALVE TEST Cooling Liq Valv Test Off/On
CCH RELAY 1 TEST Crankcase Heater 1 test Off/On
ALARM RELAY TEST Alarm Output Relay Test Off/On
PE1 RELAY TEST Power Exhaust 1 Test Off/On
PE2 RELAY TEST Power Exhaust 2 Test Off/On
2POS/ERV RLY TEST 2Position/ERV Relay Test Off/On
FAN TESTS Indoor and Outdoor Fan tests
IDF SPEED TEST Indoor Fan Speed Test 0 to 100
CONVERTED IDF RPM Converted IDF Speed XXXX
IDF MANUAL TRANS IDF Manual Transition Yes/No
COOL Cooling Status Menu
COOL A1 TEST Cooling W/Comp.A1 Test Off/On
CIR A LOADER TEST Cooling W/Comp.ALD Test Off/On
IDF SPEED TEST Indoor Fan Speed Test 0 to 100
ODF RELAY TEST ODF Speed Relay Test Off/On
HUMIDIMIZER TEST Humidimizer Level Test 0=Off
1 = SUBCOOL
2=REHEAT
HEAT Heating Status Menu
HEAT 1 TEST Heating Stage 1 Test Off/On
HEAT 2 TEST Heating Stage 2 Test Off/On
IDF SPEED TEST Indoor Fan Speed Test 0 to 100
AUTOMATIC TEST Automatic Test Menu
AUTO INDP TEST AUTO INDEPENDENT TEST Yes/No
AUTO COOL TEST RUN AUTO COOLING TEST Yes/No
AUTO HEAT TEST RUN AUTO HEATING TEST Ye s/No
AUTO SYSTEM TEST RUN AUTO SYSTEM TEST Yes/No
Automatic Test
The AUTOMATIC TEST submenu is used to execute all the
applicable tests to the system automatically. These include
independent components, cooling, heating, and system. Table 5
shows the steps taken during the independent, cooling, and
heating automatic tests. The Hold time represents the time at
which that control waits before moving on to the next step.
The AUTO SYSTEM TEST will execute the independent auto
test, then the cooling auto test, then the heating auto test. At the end
of the system auto test a prompt will ask if you want to enter
measured data and complete a service report.
Table 5 – Independent, Cooling, and Heating Automatic Tests
AUTO INDP TEST
Step Action Hold (Sec)
1Turn on Crankcase Heater Relay 0
2Set IDF speed to 100% 30
3Turn on 2 position damper/ERV relay 30
4Set Economizer Damper to 100% 60
5Turn on power exhau st 1 10
6Turn on power exhau st 2 10
7SetEconomizerDamperto0% 60
8Turn off power exhaust 2 10
9Turn off power exhaust 1 10
10 Set IDF to the ventilation speed 30
11 Turn off 2 position damper/ERV relay 0
12 Turn on alarm relay 10
13 Turn off alarm relay 10
14 Set IDF to 0% speed 30
15 Turn off Crankcase Heater relay 0
AUTO COOL TEST
Step Action Hold (Sec)
1Set IDF auto transition 0
2Turn on C o o l A1 test 60
3Turn on Compressor Loader test 30
4Turn off OD F Rel a y test 10
5Turn off Compressor Loader test 60
6Turn off Cool A1 test 30
7Turn on Hot Gas Reheat Test 60
8Switch to Subcooling Test 30
9Turn off Subcooling Test 30
AUTO HEAT TEST
Step Action Hold (Sec)
1Set IDF auto transition 0
2Turn on Hea t 1 te st 60
3Turn on Hea t 2 te st 60
4TurnoffHeat1andHeat2tests 20

12
THIRD PARTY CONTROL
Third party controls may interface with the unit SystemVut
controller through the connections described below. See other
sections of these instructions for more information on the related
unit control and configurations.
Cooling/Heating Control
The thermostat inputs are provided on TB1 of the board. The
Unit Control Type configuration, UNIT CONTROL TYPE,
must be 0 (Tstat) to recognize the below inputs. Terminal R is
the 24--VAC source for the following:
Y1 = first stage cooling
Y2 = second stage cooling
W1 = first stage heating
W2 = second stage heating
G = Indoor fan
Dehumidification Control
For units with factory installed Humidi--MiZerRsystem option, the
humidistat input is defaulted for use on the Y3 thermostat input
screw terminal as a normally open switch. This can be changed
with the Humidistat Switch Channel configuration (HUMSTAT
CHANNEL) and the Humidistat switch type configuration
(HUMSTAT SW TYPE).
Remote Occupancy
The remote occupancy input can be provided on one of the
configurable inputs, most commonly TB3. The Remote
Occupancy Switch configuration, REMOTE OCC TYPE,
identifies the normally open or normally closed status of this input
when unoccupied. The Remote Occupancy Channel configuration,
REMOTE OCC CHAN, identifies the discrete input (DI) assigned
for this function.
Remote Shutdown
The remote shutdown input is provided for unit shutdown in response
to switch input configured most commonly on TB3. The Remote
Shutdown Switch configuration, REM. SHUTDOWN TYPE,
identifies the normally open or normally closed status of this input
when there is no shutdown command. The Remote Shutdown
Channel configuration, REM. SHUTDOWN CHAN, identifies the
discrete input (DI) assigned for this function.
Alarm Output
The alarm output is provided on as a configurable relay, most
commonly on TB2, to indicate when a current alarm is active. The
output will be 24--VAC if a current alarm exists. The Alarm Relay
Channel configuration, ALM RELY CHANNEL, identifies the
discrete output (DO) assigned for this function.
Economizer Damper Control
For units with the economizer option or accessory, the damper
position can be directly controlled through the IAQ sensor input.
The IAQ Analog Input configuration, IAQ LEVEL CONTROL
will have to set to 2 (CTL MINP). When IA.CF = 2, an external 4
to 20 mA source is used to move the damper 0% to 100% directly.
CONTROLS OPERATION
Display Configuration
The SETTINGSDISPLAY SETTINGS submenu is used to
configure the local display settings.
METRIC DISPLAY
This variable is used to change the display from English units to
Metric units.
LANGUAGE
This variable is used to change the language of the SystemVu
display. At this time, only English is available.
CONTRAST ADJUST
This is used to adjust the contrast of the SystemVu display.
PASSWORD ENABLE?
This variable enables or disables the use of a user password. The
password is used to restrict use of the control to change configurations.
VIEW USER PASSWORD
This menu allows the user to view the user password. The
password must be entered or disabled to view it.
CHANGE USER PASSWORD
This menu allows the user to change the user password. The
password must be entered or disabled to change it.
Unit Configuration
Many configurations that indicate what factory options and/or field
accessories are installed and other common operation variables are
included in SETTINGSUNIT CONFIGURATION submenu.
Some of these configurations will be set in the factory for the
factory--installed options (FIOPs). Field installed accessories and
custom control functions will require configuration changes. The
SETTINGSUNIT CONFIGURATIONGENERAL submenu
contains the following control configurations. Refer to other
specific sections for other configurations.
STARTUP DELAY
This configuration sets the control start-up delay after the power is
interrupted. This can be used to stagger the start-up of multiple
units.
UNIT CONTROL TYPE
This configuration defines if temperature control is based on
thermostat inputs or space temperature sensor input. TSTAT value
is when then unit determines cooling and heating demand by the
state of G, Y1, Y2, W1, and W2 inputs from a space thermostat.
This value is the factory default. SPACE SEN value is when the
unit determines cooling and heating demand based on the space
temperature and the appropriate set point. RAT SEN value is when
the unit determines cooling and heating demand based on the
return air temperature and the appropriate set point. SPACE SEN
or RAT SEN are also used as Linkage configuration.
THERMOSTAT TYPE
This configuration applies only if Unit Control Type is Thermostat.
The value determines how the inputs are interpreted. See the
specific operation sections for more information. The following
descriptions define what each value means.
0 = CONV 2C2H – Conventional Thermostat 2 stage cool and
2 stage heat.
1 = DIGI 2C2H – Digital Thermostat 2 stage cool and 2 stage heat.
2 = CONV 3C2H – Conventional Thermostat 3 stage cool and
2 stage heat. This is the default setting.
3 = DIGI 3C2H – Digital Thermostat 3 stage cool and 2 stage heat.
ADAPTIVE TSTAT
This configuration applies only if the Unit control type is
Thermostat. When this is YES the control will use Adaptive
Control for cooling and heating staging. When this is set to NO the
control will use the Traditional Thermostat Control, however
during integrated cooling Adaptive is always used.
DIRTY FILTER TIME
This configuration defines the life of the installed filter. A timer
will count down from this number while the indoor fan is running.
At the expiration of this timer, an alert will be activated to indicate
a filter change is required.
TEST MODE TIMEOUT
This configuration defines the time at which a test mode test has
not changed state will automatically disable test mode. This
configuration will disable the timeout when set to 0 (Disabled).

13
CCH MAX TEMP
This configuration defines the temperature threshold for which the
crankcase heater is no longer required to heat the compressor shell.
STD BARO PRESSURE
This configuration is used to specify the job location’s standard
barometer pressure reading. This will feed the BAROMETRIC
PRESS when a network is not writing to it. This should be used to
account for job site elevation if enthalpy calculations are being used.
LINK STAGEUP TIME
This configuration sets the cooling and heating stage up time
during linkage operation.
Configurable Switches and Analog sensors
The SystemVutcontroller has optional configurable inputs. These
consist of five physical board switch inputs (discrete inputs) and three
physical board analog inputs. There are more functions allowed for
configuration than there are inputs. Each function will have a
configuration for which input channel it is assigned to. Each switch
function will also have a switch type configuration which defines that
switches normal state. Table 6 shows the configurable functions and
what their normal and active states are. Table 7 shows the configurable
analog input functions. The switch configurations can be found in the
SETTINGSUNIT CONFIGURATIONSSWITCH INPUT
CONFIGS sub--menu. The analog input configurations can be found
in the SETTINGUNIT CONFIGURATIONSSWITCH INPUT
CONFIGS sub--menu. The configurable input assignment can be
viewed in the SERVICEHARDWAREASSIGNED
INPUTS/OUTPUTS sub--menu.
Table 6 – Configurable Switch Input Functions
Function Description Normal State Active State
Humidistat OFF ON
Condensate Overflow LOW HIGH
Phase Monitor NORMAL ALARM
Filter Status Switch CLEAN DIRTY
Remote Occupancy UNOCC OCCUPIED
Remote Shutdown RUN SHUTDOWN
Fan Status OFF ON
General Status Switch NORMAL ALARM
IAQ Override OFF ON
Enthalpy Switch Input LOW HIGH
Table 7 – Configurable Analog Input Functions
Function Description Sensor Type Sensor Values
Space Relative Humidity Sensor 0 --- 20mA %RH
Outside Air Relative Humidity Sensor 0 --- 20m A %RH
Return Air Relative Humidity Sensor 0 --- 2 0mA %RH
Indoor Air CO2Sensor 0 --- 2 0mA PPM
Outside Air CO2Sensor 0 --- 2 0m A PPM
Outdoor CFM Sensor 0 --- 20mA CFM
General Operation
48/50FC and 48/50GC units can provide cooling,
dehumidification, heating, and ventilation. The operating mode
(MODE) shows the highest level of operation of the unit at any
given time. The operating sub--mode (SUB--MODE) shows the
detail operation occurring while under a specific mode. Fig. 8
shows the MODE and SUB--MODE values.
Each unit will operate under one of three basic types of control,
thermostat, space temperature sensor, or return air temperature
sensor. There are many inputs, configurations, safety factors, and
conditions that ultimately control the unit. Refer to the specific
operation sections for detail on a specific unit operation. The
control will set the demand based on these types of control and
conditions, which then drives the operating mode.
When thermostat control is enabled (UNIT CONTROL TYPE),
the unit will operate based on discrete input commands (G, Y1,
Y2, W1, and W2) and there is a one minute time delay between
modes and when re--entering a mode. The G command calls for
ventilation, the Y1 and Y2 commands call for cooling, and the W1
and W2 commands call for heating. Thermostat Control Type
(THERMOSTAT TYPE) affects how cooling operates based on
Y1 and Y2 commands and if cooling/heating stage time guards are
applied.
When space temperature sensor control in enabled (UNIT
CONTROL TYPE), the unit will try to maintain the Space
Temperature (SPACE TEMPERATURE) between the effective
cool and heat setpoints (EFF COOL SETPOINT and EFF HEAT
SETPOINT). However, to minimize unnecessary cool to heat and
heat to cool changes, there is a 10 minute delay after the last stage
turns off before the control will switch modes. Linkage operation
overrides the mode changeover delay to 15 seconds. The cooling
and heating Mode Select Time guards (COOL MODE T.GUARD
and HEAT MODE T.GUARD) show the remaining time before
allowing the respective mode to be entered.
Demand Determination
Based on the unit control type (UNIT CONTROL TYPE),alarm
conditions, and user interaction, the control will determine an
overall demand of the unit. Table 8 shows the possible system
demands with their priority level and summary description.
Thermostat Demand
When the unit control type is configured for thermostat (UNIT
CONTROL TYPE = TSTAT) the level 5 demand in Table 8 will be
determined by thermostat inputs and the Thermostat Type
configuration (THERMOSTAT TYPE) as shown in the tables
below. Table 9 shows the cooling thermostat inputs and how they
map to the system demand. Table 10 shows the heating thermostat
inputs and how they map to the system demand.
SUB-
MODE
IDLE - NO DEMAND SUPPLY FAN ON UNOCC. FREE COOL
MODE TIMEGUARD MECH. COOLING
UNIT DISABLED ECON/MECH COOLING
URGENT SHUTDOWN DEHUMIDIFICATION
SAFETY CONTROL DEHUM/MECH COOL
MODE OFF VENT COOL HEAT TEST
STARTING UP MODE TIMEGUARD ECON FREE COOLING HEATING MANUAL TEST
OUTSIDE AIR TEMPERING
HEATING PREVENTED
AUTO TEST
SHUTTING HEAT OFF
SHUTTING TEST OFF
DEHUM PREVENTED
COOLING PREVENTED
SHUTTING COOL OFF
a48---9374
Fig. 8 -- Modes and Sub--Modes

14
Table 8 – Demand List and Priority
DEMAND Priority Description
EMERGENCY 1An emergency condition occurs which requires a unit shutdown
SAFETY FAULT 2A safety diagnostic requires the unit to run in safety mode.
SERVICE TEST 3User request test mode
SHUTDOWN 4A minor or user condition requires the unit to shutdown
NO DEMAND
5
There is no comfort demand from the building
FAN ONLY Only circulation or ventilation is requested form the building
DEHUM A dehumidification load is present in the building
LOW COOL A low cooling load is present in the building
HIGH COOL A high cooling load is present in the building
LOW COOL & DEHUM A low cooling and dehumidification load is present in the building
HIGH COOL & DEHUM A high cooling and dehumidification load is present in the building
UFC LOW COOL A low cooling load is present in the building due to the unoccupied free cooling algorithm
UFC HIGH COOL A high cooling load is present in the building due to the unoccupied free cooling algorithm
LOW HEAT A low heating load is present in the building
HIGH HEAT A high heating load is present in the building
SUPPLY AIR TEMPERING Due to outside air, supply air is uncomfortably cool during ventilation
Table 9 – Thermostat Cooling System Demands
Thermostat Inputs THERMOSTAT TYPE
Y1 Y2 CONV 2C2H* CONV 3C2H DIGI 2C2H DIGI 3C2H
0 0 No Cool No Cool No Cool No Cool
0 1 Alert & Low Cool Alert & Low Cool High Cool High Cool
1 0 Low Cool Low Cool Low Cool Low Cool
1 1 High Cool High Cool High Cool High Cool
*SettheLOW COOL COMP as needed.
Table 10 – Thermostat Heating System Demands
Thermostat Input THERMOSTAT TYPE
W1 W2 CONV 2C2H
CONV 3C2H
DIGI 2C2H
DIGI 3C2H
0 0 No Heat No Heat
0 1 Alert & Low Heat High Heat
1 0 Low Heat Low Heat
1 1 High Heat High Heat
Space Sensor Demand
When the unit control type is configured for space sensor (UNIT
CONTROL TYPE = SPACE SEN) the level 5 demand in Table 8
will be determined by the space sensor inputs and setpoints as
described below. The Effective Demand Temperature (DEMAND
CTRL TEMP) represents the temperature which the control is
using to control the space. This would come from the space sensor,
building network, linkage, or the return air sensor.
Setpoint Determination
Setpoints are used to control the unit. The Cool Setpoint in Effect
(EFF COOL SETPOINT) and the Heat Setpoint in Effect (EFF
HEAT SETPOINT) are the points in which the unit is controlling
to at a specific time. These points are read only points and change
according to occupancy, the offset slider status, and network writes.
The setpoint configurations are in the SETTINGSSPACE SET
POINTS submenu.
If the building is in occupied mode, the Occupied Cool Setpoint
(OCC COOL SETPOINT) and the Occupied Heat Setpoint (OCC
HEAT SETPOINT) are active. When the building is in
unoccupied mode, the Unoccupied Cool Setpoint (UNOCC COOL
SETPNT) and the Unoccupied Heat Setpoint (UNOCC HEAT
SETPNT) are active. The heating and cooling set points are also
separated by a Heat--Cool Set Point Gap (HEAT- COOL SP GAP)
that is user configurable from 2 to 10 degrees F. This parameter
will not allow the setpoints to be set too close together, it will
change the last setpoint adjusted if it is set within the GAP.
When the space sensor has a setpoint slider adjustment, the cool
and heat setpoints (occupied) can be offset by sliding the bar from
one side to the other. The SPT Offset Range (+/--) (SPT SLIDER
RANGE) sets the total positive or negative degrees that can be
added to the setpoints. With the slider in the middle, no offset is
applied. Moving the slider to the “COOL” side will subtract from
each setpoint, and sliding it to the “WARM” side will add to the
setpoints. The slider offset being applied at any given time is
displayed as Space Temperature Offset (SLIDER OFFSET VAL).
Temperature Demand
Space sensor staging control is an adaptive anticipation control that
weighs the actual space demand against the trend of that demand.
The control tries to anticipate the change in the space because of its
current stage status. This anticipation is based on the demand
trends. These trends will show the control how the space is reacting
to the current running conditions and help it decide when to
change the actual demand of the system. The following points are
in the RUN STATUSMODE submenu:
COOLING DEMAND — This is the difference between the Cool
Setpoint in Effect (EFF COOL SETPOINT) and the Effective
Demand Temperature (DEMAND CTRL TEMP) representing the
demand of the space for cooling.
COOL DEMAND TREND — This is the rate of change of the
cooling demand in degrees per minute, representing how the space
is changing its demand for cooling.
HEATING DEMAND — This is the difference between the Heat
Setpoint in Effect (EFF HEAT SETPOINT) and the Effective
Demand Temperature (DEMAND CTRL TEMP) representing the
demand of the space for cooling.
HEAT DEMAND TREND — This is the rate of change of the
heating demand in degrees per minute, representing how the space
is changing its demand for cooling.
In general the system demand will increase based on the demand
compared to the demand switch states in Fig. 9. The demand
cannot increase until Time guard 1 (DEMAND TIMEGUARD1)
expires. The LCON and LHON thresholds will also cause the

15
system demand to be reduced. When the demand hits the off switch
stages the system demand will be set to NO DEMAND. These
switch stages are in the SETTINGSSET POINTSTEMP
DEMAND CONFIG submenu.
The cooling and heating demand level up configurations (COOL
DMD LEVEL UP and HEAT DMD LEVEL UP) will restrict a
system demand increase if the demand trend is less than the level
up configuration. These level up configurations will also increase
the system demand if the demand trend is greater than it for greater
than the Time guard 2 (DEMAND TIMEGUARD2).
The system demand will increase if it has remained at the same
state for greater than Time Guard 3 (DEMAND TIMEGUARD3).
Cool Setpoint
Heat Setpoint
LCON
LHON
HCON
HHON
LHOF
LCOF
Decrease
Demand
Decrease
Demand
SPACE TEMP
a48---10313
Fig. 9 -- Space Sensor System Demand Switch States
RAT Demand
When the unit control type is configured for return air sensor
(UNIT CONTROL TYPE = RAT SEN) the level 5 demand in
Table 8 will be determined the same as space sensor but using the
return air temperature (RETURN AIR TEMP) instead of the space
temperature (SPACE TEMPERATURE).
Humidity Demand
When the unit is configured for either a Humidistat input
(HUMSTAT CHANNEL) or Space Humidity Sensor (SPRH
SENS CHANNEL) the level 5 demand in Table 8 will include a
determination of dehumidification demand.
Humidistat
When receiving an active input from the Humidistat
(HUMIDISTAT), dehumidification will be demanded.
Space Relative Humidity
On units with a relative humidity sensor, when the received value
of space relative humidity (SPRH LEVEL) has exceed the
humidity set point (SPRH SET POINT), dehumidification will be
demanded. This demand will remain until the space relative
humidity has fallen below the humidity set point by more than the
humidity set point deadband (SPRH DEADBAND). This would
come from the space humidity sensor, or building network.
Occupancy Determination
The building’s occupancy is affected by a number of different
factors. Occupancy affects the unit set points and the operation of
the economizer. The factors affecting occupancy are listed below
from highest to lowest priority.
Level 1 Priority
Level 1 classification is a force/write to occupancy and can occur
two ways. Listed in order of priority: force on OCCUPIED, and a
Linkage write. The CCN point OCCUPIED is forced via an
external device such as a ComfortIDtcontroller or a service tool:
when OCCUPIED is forced to YES, the unit is considered
occupied, when OCCUPIED is forced to NO, the unit is
considered unoccupied. If the unit is being controlled by Linkage,
the occupancy is communicated and mapped to OCCUPIED as an
input. Linkage does not force the point only write to it, therefore a
force applied to OCCUPIED will override it.
If OCCUPIED is not being forced or written to, proceed to the
level 2 priority.
Level 2 Priority
Level 2 is considered occupant interaction, and consists of Timed
Override and Remote Occupancy Switch. A timed override button
press will override a remote occupancy switch if both are installed
for operation.
While using the programmed schedule, occupancy can be
temporarily switched from unoccupied to occupied by pressing the
override button for approximately 3 seconds on the T--55, T--56, or
T--59 space temperature sensor. The length of the override period
when pressing the override button is determined by the Override
Time Limit (TIMED OVR LENGTH). The hours remaining in
override is displayed as Timed Override Hours (TIMED OVR
HOURS). This point can also be changed from the local display or
network to set or change the override period length.
Remote Occupancy Switch (REMOTE OCC SWITCH) can be
forced or configured for operation based on an actual switch. The
physical switch should be configured to either Normally Open or
Normally Closed when the user would like to control the
occupancy with an external switch. This switch is field--supplied
(24v, single pole, single throw [SPST]). There are two possible
configurations for the remote occupancy switch:
1. (REMOTE OCC TYPE = 0) Normally Open Switch
2. (REMOTE OCC TYPE = 1) Normally Closed Switch
If the switch is configured to No Switch (REMOTE OCC CHAN =
None), the switch input value will be ignored and software will
proceed to level 3 priority. For each type of switch, the appropriate
configuration and states are listed in the table below.
TYPE OF SWITCH SWITCH
CONFIGURATION
STATE OF SWITCH
AND STATE OF
OCCUPANCY
Occupied when
Closed or Unoccupied
when Open
Normal Open (0)
Open and Unoccupied
Closed and Occupied
Occupied when Open
or Unoccupied when
Closed
Normal Closed (1)
Open and Occupied
Closed and
Unoccupied
Level 3 Priority
The following occupancy options are determined by the state of
Occupancy Schedule Number (SCHEDULE NUMBER) and the
Global Schedule Broadcast (BROADCAST SCHEDL?).
1. (SCHEDULE NUMBER = 0) The unit is always
considered occupied and the programmed schedule is
ignored. This is the factory default.
2. (SCHEDULE NUMBER = 1- 64) Follow the local
programmed schedule. Schedules 1 to 64 are local within
the controller. The unit can only store one local schedule
and therefore changing this number only changes the title of
the schedule table.
3. (SCHEDULE NUMBER = 65- 99) Follow the global
programmed schedule. If the unit is configured as a Global
Schedule Broadcaster (BROADCAST SCHEDL? = YES),
the unit will follow the unit s programmed schedule and
broadcast the schedule so that other devices programmed to
follow this schedule number can receive the schedule. If the
unit is not programmed as a Global Schedule Broadcaster
(BROADCAST SCHEDL? = NO), the unit will receive
broadcasted schedules from a unit programmed to broadcast
this schedule number.

16
Indoor Fan Operation
These units use the Staged Air Volume (SAV) method of controlling
the supply fan for a typical constant volume rooftop unit. This control
method employs an Electronic Commutated Motor (ECM) to
operate the supply fan at different speeds in order to achieve energy
savings through reduced fan power. This method is specifically not
concerned with controlling static pressure in the supply duct, but rather
with setting different fan speeds for different operating conditions,
such as ventilation mode or part--load mechanical cooling.
The SAV function is NOT a Variable Air Volume (VAV) function.
The fan adapts its speed to one of eight based on mode and current
state to satisfy a demand. The eight speeds consist of off (0%) and
seven configurable values. The seven configurable fan speeds are:
Maximum Speed (MAXIMUM IDF SPEED), Ventilation (VENT
IDF SPEED), Heating (HEATING IDF SPD), Free Cool (FREE
COOL IDF SPD), Mechanical Low Cooling (LOW COOL IDF
SPD), Mechanical Medium Cooling (MED COOL IDF SPD),and
Mechanical High Cooling (HIGH COOL IDF SPD),TheECMis
powered direct from the distribution block and is always on with
power applied unless the CB is tripped. When the thermostat or
space sensor control conditions require the fan on, the ECM will
then be ramped to desired speed. Fan speed is always calculated by
evaluating the current applicable conditions. Each fan speed
condition is evaluated independently, and the highest fan speed is
used. For example, if a cooling call occurs during Ventilation
mode, the unit mode will transition to cooling but the fan speed is
set to the higher of the two (VENT IDF SPEED or LOW COOL
IDF SPD). Refer to the speed configurations below for when the
fan will run at them.
The Commanded Fan Speed (OUTPUTSGENERAL
OUTPUTSCOMMANDED IDF RPM) represents the controls
commanded speed for the fan at any given time. This commanded
speed is determined by the unit’s current HVAC mode and the unit
control type. For gas heating units, the IGC fan request output
(InputsGEN.IIGC.F) is monitored by the control. This can result
in additional modification of fan delays or other operation due to
safety functions of the IGC control. See the Gas Heating operation
section for more details. If configured for IAQ fan operation, the fan
may be turned on to satisfy air quality demands. See the Indoor Air
Quality section if using IAQ (indoor air quality) accessory sensors.
The fan can run under thermostat or space sensor control and will
remain on if compressors or heat relays are ever stuck on. If Shut
Down on IDF Failure is enabled (SHUTDOWN IDF FAIL = Yes),
the fan and unit will be shutdown without delay on fan alarm
conditions. Fan off delays are honored when exiting specific HVAC
modes. The Fan--off Delay delays are as follows: Cooling (COOL
FANOFF DELAY), and Heating (HEAT FANOFF DELAY).
Indoor (Supply) Fan Maximum Speed
(MAXIMUM IDF SPEED)
Max speed is the highest fan speed allowed. This is typically set to
deliver design CFM to the space per job requirement. Most safety
conditions for the unit will override the fan speed to this to help
protect the unit.
IMPORTANT: MAXIMUM IDF SPEED is used in the minimum
position curves and therefor important to set properly.
Ventilation Indoor Fan Speed (VENT IDF SPEED)
This configuration defines the fan speed used in Ventilation
(fan--only) mode. Ventilation mode is when the supply fan is
running, but there is no demand for heating or cooling. In
thermostat mode, this is with just a G call. In space sensor control,
this is when the unit is Occupied mode and the indoor fan is
configured to always run while occupied (OCCUPIED FAN?).If
the indoor fan is configured for intermittent fan (OCCUPIED
FAN? = No), the Mode will be off instead of Ventilation and the
fan will not run unless a heating or cooling mode is needed. During
the unoccupied period, the fan will always operate intermittently.
The economizer damper will adjust its position based on how far
away this speed is from max speed for ventilation.
IMPORTANT: It is important that the ventilation rate is checked after
setting this speed to verify that the unit can properly ventilate the space
per requirements. Adjusting this configuration or the economizer
minimum setting curve should be performed to meet job requirements.
Heating Indoor Fan Speed (HEATING IDF SPD)
This configuration defines the fan speed used when in heating
mode and running heat. On units equipped with Gas heat (UNIT
TYPE OF HEAT), this heat speed will be delayed on based on the
IGC’s fan on call (IGC FAN REQUEST). Once the IGC request
the fan the fan will run what this heating speed configuration is set
for until heating is ended. On units configured for Electric heat
(UNIT TYPE OF HEAT) and configured for Preheat without the
fan (PREHEAT W/O IDF), this heat speed will be delayed on
based on the Preheat fan delay time (PREHEAT FAN DELAY).
Once this preheat time has expired or not configured for preheat,
the fan will run at this heat speed while heat is on.
Free Cooling Indoor Fan Speed (FREE COOL IDF SPD)
This configuration defines the initial fan speed used when in Free
Cooling. Refer to the Economizer Controls Operation section for
details on free cooling. The fan will stay at this configured speed
whenever only the damper is being used for free cooling. If the
damper is at 100% for 5 minutes the fan will ramp to the high
cooling speed. It is locked there until the actual damper position
falls below 75% at which time it will ramp back down to this
configured speed.
Low Cooling Indoor Fan Speed (LOW COOL IDF SPD)
This configuration defines the fan speed used when the first stage
of mechanical cooling is being performed.
High Cooling Indoor Fan Speed (HIGH COOL IDF SPD)
This configuration defines the fan speed used when all (full load)
stages of mechanical cooling is being performed. When performing
integrated cooling with the economizer this speed will be used. When
only free cooling with a high cool demand, this speed will be used.
Cooling Operation
The unit’s cooling operation consists of: demand and mode
determination, staging request to satisfy the demand, and handling
a request with the unit’s resources. These resources can include
compressors, Humidi--MiZerRsystem, an economizer, and fan
speed based on options. This section covers mechanical cooling.
For economizer free cooling, refer to the Economizer Operation
section (starting on page 22).
For Humidi--MiZer system operation, refer to the Optional
Humidi--MiZer Dehumidification System section (see page 17).
Cooling Mode Control
The cooling HVAC mode (OPERATING MODE) has 9 different
operating sub modes (SUBMODE): ECON FREE COOLING,
UNOCC. FREE COOL, MECH. COOLING, ECON/MECH
COOLING, DEHUMIDIFICATION, DEHUM/MECH COOLING,
DEHUM PREVENTED, COOLING PREVENTED, and
SHUTTING COOL OFF. These are all part of a general cooling
mode and resemble the specific type of cooling that is being
performed at any given time. All types of cooling are still performed
under the general cooling function, and the expanded text is for user
reference only.
For the unit to enter cooling mode, three things must be true: the
indoor fan must be ok to use, the mode changeover time guard must
be expired, and there must be a cooling or dehumidification demand
(Y1, Y2, space cool demand, or humidity demand). The unit will
remain in cooling for at least one minute or until any of the above
conditions turn false. The cooling mode does not officially end until
the compressor is off and the fan off delay has expired.

17
Cooling Staging Control
Once the unit is in a cooling mode, determine what the demand is
and how to satisfy it. If an economizer is installed and can be used
for cooling (OK TO USE FREE COOLING? = Yes), the unit will
use it first (see economizer section for its operation). If the
economizer cannot be used or additional cooling is needed, a
mechanical cooling check is performed. OK to use Compressors?
(OK TO USE COMPS?) will be set to yes when the outdoor
temperature (OUTDOOR AIR TEMP) is above the Circuit A
Lockout temperature (CIR.A LOCKOUT OAT) and the Circuit A
is not locked out for diagnostic reasons (CIRCUIT A LOCKOUT).
Based on the unit control configuration, requested cooling stages
(REQ. COOL STAGES) will be determined then passed to
compressor control to actually add the cooling stages.
There are two ways of requesting stages when thermostat control is
enabled, Traditional thermostat control or adaptive control.
Traditional thermostat control is used if set for non--adaptive
thermostat (ADAPTIVE TSTAT = NO) and the unit cannot use the
economizer for free cooling. If set for adaptive thermostat
(ADAPTIVE TSTAT = YES) or any time the economizer is
available for free cooling, the unit will use adaptive control for
staging.
When configured for Space sensor or RAT control (UNIT
CONTOL TYPE) the unit will use adaptive control for staging.
With either staging method there are two supply air temperature
limits that apply, one restricts more cooling stages and the other
will remove cooling stages. If at any time the Supply--Air
Temperature (SUPPLY AIR TEMP) falls below the Minimum
Supply Air Temperature Upper Level (UPPER MIN SAT),the
requested stages will not be allowed to increase. If at any time the
SAT falls below the Minimum Supply Air Temperature Lower
Level (LOWER MIN SAT), the requested stages will be reduced
by one. If these SAT limits are configured so that they are too close
together, the last stage might cycle rapidly, slowed only by its
minimum on and off--time requirements.
Adaptive Control
Stage timers and Supply air trend apply when determining the
request for stages. The first request (REQ. COOL STAGES =1)
comes immediately when starting the staging process. The Cool
Stage Increase Time (COOL STAGEUP TIME) has to expire and
the Supply--Air Trend (SUPPLY AIR TREND) has to be above
the cooling supply air trend level (COOL SATTREND LEV)
before another stage can be added. Requested stages will only be
allowed to increase as the actual system demand allows
(DEMAND). A “LOW COOL” demand will only allow one
requested stage, and “HIGH COOL” all stages. The requested
stages will be reduced if the cooling demand is lowered or dropped
completely, or if the supply air falls below the lower level
(LOWER MIN SAT).
Traditional Thermostat Control
Stage timers and Supply air trend do not apply when determining the
request for stages. Request staging will follow the thermostat inputs
directly. “LOW COOL” will request one stage.“HIGH COOL” will
request two stages.
Compressor Control
The compressor control works hand and hand with the staging
control. As the staging control request stages, the compressor control
determines what is available or running and tries to provide stages for
what is requested. The availability of the compressors depends on
time guards, circuit diagnostics, and outdoor temperature.
There are time guards to protect the compressor, Compressor Min
On Time (COMP MIN ON TIME) and Compressor Min Off Time
(COMP MIN OFF TIME) apply before the compressor can be
turned back on or turned off. Timeguard A1 (COMP A1
TIMEGUARD) and Timeguard loader (COMP LDR
TIMEGUARD) display the time the compressor and loader have
before available for use.
Circuit diagnostic tests are performed during operation which may or
may not allow the compressor to be used. The availability of the
compressor is shown as Compressor A1 Available (COMP A1
AVAILABLE). The lockout status of the compressor is shown as
Compressor A1 Lockout (COMP A1 LOCKOUT). The actual stages
running at any given time is displayed as Actual Cooling Stages
(ACTIVE COOL STAGE). Individual compressor output state is
shown as (COMPRESSOR A1) and (COMP A LOADER).
Any time the outdoor ambient falls below the low cooling minimum
outdoor temperature (LOW COOL MIN OAT), the low cooling
lockout will be active (LOW COOL LOCKOUT) preventing
compressor A1 from running by itself. This means the loader will be
on with the compressor.
Outdoor Fan Control
The outdoor fan can be set for a single speed or 2 speed motor. The
3 to 5 ton 48/50FC units will have a single speed ODF. The 3 to 5
ton 48/50GC and the 6 ton 48/50FC will have a 2 speed ODF. The
ODF Relay Enabled (ODF RELAY ENABLE) point will tell the
control when a 2 speed motor is installed. The 2 speed relay state
output is shown as Outdoor Fan Speed Relay (ODF SPEED
RELAY). Units with a low ambient option or Humidi--MiZerR
option will also be equipped with a head pressure control device.
Normal Operation
On the single speed ODF system, the ODF will come on and off with
the compressor. On the 2 speed ODF systems, the ODF will come on
and off with the compressor at low speed. The High speed ODF will
be active when the compressor loader is on, and done by energizing
the ODF SPEED RELAY.
Low Ambient Operation
When equipped with the head pressure device and the OAT is
below approximately 40_F, the ODF speed will vary based on the
condensing temperature. Regardless of active low or high speed the
head pressure device will modulate the ODF speed to maintain
approximately 95_F temperature at the coil sensor location. In low
speed operation however the head pressure device cannot use high
speed if needed until the control turns on the ODF SPEED
RELAY.
Humidi--MiZerROperation
When equipped with the head pressure device and reheat is active, the
ODF speed will vary based on the condensing temperature. Regardless
of active low or high speed the head pressure device will modulate the
ODF speed to maintain approximately 95_F temperature at the coil
sensor location. In low speed operation however the head pressure
device cannot use high speed if needed until the control turns on the
ODF SPEED RELAY.
Optional Humidi--MiZer Dehumidification System
Units with the factory--installed Humidi--MiZer system option are
capable of providing multiple modes of improved
dehumidification as a variation of the normal cooling cycle. The
Humidi--MiZer system option includes additional valves in the
liquid line and discharge line of the refrigerant circuit and a reheat
coil downstream of the evaporator. The Humidi--MiZer system
equipped configuration is factory set to Yes for Humidi--MiZer system
equipped units (REHEAT EQUIPPED = YES). This enables
Humidi--MiZer system operating modes and service test.
Humidi--MiZer system operation requires the installation and
configuration of a relative humidity switch input or a space relative
humidity sensor. These provide the dehumidification demand to the
control.
Dehumidification Demand
When using a humidistat or switch input, the demand for
dehumidification is seen as Space Humidity Switch
(INPUTSSWITCH INPUTSHUMIDISTAT) being Off or On.
An Off value means humidity level is good and an On value means
that dehumidification is needed.

18
When using an SPRH sensor, the demand is based on the Space
Humidity Sensor (INPUTSANALOG INPUTSLEVEL) value
compared to the Space RH Setpoint (SETTINGSSPACE
SETPOINTSOCC SPRH SETPOINT or UNOCC SPRH SP).If
the Space Humidity Sensor (SPRH) value is above the Space RH
Setpoint, then dehumidification is needed. If the Space Humidity
Sensor (SPRH) value is below the Space RH Setpoint minus the
Space RH Deadband (SETTINGSCOOLINGSPRH
DEADBAND), then dehumidification is no longer needed.
NOTE: When there is a dehumidification demand, the economizer
damper position is limited to its minimum damper position.
Humidi--MiZerRSystem Modes
With Humidi--MiZer system units there are two additional HVAC
modes available for the user: Dehumidification and Dehum/Mech
Cooling. Selection of the Dehum/Mech Cooling mode is
determined by the dehumidification demand and the cooling
demand. Table 11 shows the corresponding circuit mode and
output status for the different demand combinations.
Normal Cooling
This mode is the standard rated cooling system performance, and
occurs when there is cooling demand without dehumidification
demand.
For 48/50FC 04--06 units, refrigerant flows through the outdoor
condenser and is diverted away from the reheat coil with the open
Cooling Liquid Valve (CLV) into the expansion device. Figure 10
shows the complete refrigerant flow.
For 48/50GC 04--06 and 48/50FC 07 units, refrigerant flows
through the outdoor condenser and is diverted away from the
reheat coil with the closed Reheat Liquid Valve (RLV) and open
Cooling Liquid Valve (CLV) into the expansion device. Figure 11
shows the complete refrigerant flow.
Dehum/Mech Cooling (Subcooling) Mode
This mode increases the latent heat removal and decreases sensible
cooling compared to normal cooling. This occurs when there is a
cooling and dehumidification demands.
For 48/50FC 04--06 units, refrigerant flows through the outdoor
condenser and is diverted through the reheat coil with the closed
Cooling Liquid Valve (CLV) into the expansion device. Figure 12
shows the complete refrigerant flow.
For 48/50GC 04--06 and 48/50FC 07 units, refrigerant flows
through the outdoor condenser and is diverted through the reheat
coil with the open Reheat Liquid Valve (RLV) and closed Cooling
Liquid Valve (CLV) into the expansion device. Figure 13 shows
the complete refrigerant flow.
Dehumidification (Hot Gas Reheat) Mode
This mode provides maximum latent cooling with little to no
sensible capacity. This occurs when there is a dehumidification
demand and no cooling demand.
For 48/50FC 04--06 units, refrigerant flows through the outdoor
condenser and mixes with hot gas bypassing the condenser, then
diverted through the reheat coil with the closed Cooling Liquid
Valve (CLV) into the expansion device. Figure 14 shows the
complete refrigerant flow.
For 48/50GC 04--06 and 48/50FC 07 units, refrigerant flows
through the outdoor condenser and mixes with hot gas bypassing
the condenser, then diverted through the reheat coil with the open
Reheat Liquid Valve (RLV) and closed Cooling Liquid Valve
(CLV) into the expansion device. Figure 15 shows the complete
refrigerant flow.
Reheat Control
When there is only a cooling demand, the unit will operate in
normal cooling mode. When there is only dehumidification
demand, the unit will operate in Dehumidification mode (Hot Gas
Reheat). When there is both cooling demand and dehumidification
demand, the unit will operate in Dehum/Mech Cooling mode
(Subcooling). During Dehumidification and Dehum/Mech cooling
mode, the unit will run all cooling stages. The unit can be restricted
from reheat operation by the outside temperature HUMZ
LOCKOUT OAT (SETTINGSUNIT CONFIGURATIONS
COOLINGDEHUMIDIFICATIONREHEAT OAT LIMIT)
sets the lowest outside temperature the unit is allowed to run reheat
control (Default = 40_F).
Table 11 – Humidi--MiZer System Control Modes -- Sizes 04--07
DEMAND AND MODE OUTPUTS
Dehumidification
Demand Cooling Demand Mode Compressor RDV CLV
RLV
(48/50FC 07 and
48/50GC 04 --- 06 only)
No Power No Power No power Off De---energized
(no flow)
D e --- e n e r g i z e d
(flow)
De---energized
(flow)
No No Off Off De---energized
(no flow)
D e --- e n e r g i z e d
(flow)
Energized
(no flow)
No Ye s COOL On De---energized
(no flow)
D e --- e n e r g i z e d
(flow)
Energized
(no flow)
Ye s Ye s DEHUM/MECH
COOL On De---energized (no flow)
Energized
(no flow)
De---energized
(flow)
Yse No DEHUM On Energized
(flow)
Energized
(no flow)
De---energized
(flow)

19
CONDENSER COIL HUMIDI-MIZER COIL
EVAPORATOR COIL
COMPRESSOR
OUTDOOR AIR
INDOOR LEAVING
AIR
INDOOR ENTERING
AIR
RDV
VALVE
CLV
VALVE
REHEAT MODE
METERING
DEVICE (TXV)
= CLOSED VALVE
= OPEN VALVE
a48---9191
Fig. 10 -- Normal Cooling Mode – Humidi--MiZer System with Single Stage Cooling, 48/50FC 04--06
HUMIDI-MIZER COIL
COMPRESSOR
OUTDOOR AIR
INDOOR SUPPLY
AIR
INDOOR RETURN
AIR
RLV
VALVE
EXPANSION
VALVE
(TXV)
= CLOSED VALVE
= OPEN VALVE
RDV
VALVE
EVAPORATOR COIL
CONDENSER COIL
CLV
VALVE
a48---10188
Fig. 11 -- Normal Cooling Mode – Humidi--MiZer System with 2 Stage Cooling, 48/50GC 04--06 and 48/50FC 07
RDV
VALVE
CLV
VALVE
CONDENSER COIL HUMIDI-MIZER COIL
EVAPORATOR COIL
COMPRESSOR
OUTDOOR AIR
INDOOR LEAVING
AIR
INDOOR ENTERING
AIR
REHEAT MODE
METERING
DEVICE (TXV)
= CLOSED VALVE
= OPEN VALVE
Subcooling Mode (Reheat 1) − Humidi−MiZer System with Single Stage Cooling
a48---9192
Fig. 12 -- Subcooling Mode – Humidi--MiZer System with Single Stage Cooling, 48/50FC 04--06

20
HUMIDI-MIZER COIL
COMPRESSOR
OUTDOOR AIR
INDOOR SUPPLY
AIR
INDOOR RETURN
AIR
RLV
VALVE
CLV
VALVE EXPANSION
VALVE
(TXV)
RDV
VALVE
EVAPORATOR COIL
CONDENSER COIL
= CLOSED VALVE
= OPEN VALVE
a48---10189
Fig. 13 -- Subcooling Mode – Humidi--MiZer System with 2 Stage Cooling, 48/50GC 04--06 and 48/50FC 07
RDV
VALVE
CLV
VALVE
CONDENSER COIL HUMIDI-MIZER COIL
EVAPORATOR COIL
COMPRESSOR
OUTDOOR AIR
INDOOR LEAVING
AIR
INDOOR ENTERING
AIR
REHEAT MODE
METERING
DEVICE (TXV)
= CLOSED VALVE
= OPEN VALVE
a48---9193
Fig. 14 -- Hot Gas Reheat Mode – Humidi--MiZer System with Single Stage Cooling, 48/50FC 04--06
HUMIDI-MIZER COIL
COMPRESSOR
OUTDOOR AIR
INDOOR SUPPLY
AIR
INDOOR RETURN
AIR
RLV
VALVE
CLV
VALVE
RDV
VALVE
EVAPORATOR COIL
CONDENSER COIL
= CLOSED VALVE
= OPEN VALVE
EXPANSION
VALVE
(TXV)
a48---10190
Fig. 15 -- Hot Gas Reheat Mode – Humidi--MiZer System with 2 Stage Cooling, 48/50GC 04--06 and 48/50FC 07