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3
GENERAL
This book contains Controls, Start-Up, Operation, Service and
Troubleshooting information for the 48/50A Series rooftop
units. See Table 1. These units are equipped with
Comfort
Link
controls. Use this guide in conjunction with the separate instal-
lation instructions packaged with the unit. Refer to the Wiring
Diagrams literature for more detailed wiring information.
The A Series units provide ventilation, cooling, and heating
(when equipped) in variable air volume (VAV), variable volume
and temperature (VVT
®
), and constant volume (CV) applica-
tions. The A Series units contain the factory-installed
Com-
fort
Link control system which provides full system manage-
ment. The main base board (MBB) stores hundreds of unit
configuration settings and 8 time of day schedules. The MBB
also performs self diagnostic tests at unit start-up, monitors the
operation of the unit, and provides alarms and alert information.
The system also contains other optional boards that are connect-
ed to the MBB through the Local Equipment Network (LEN).
Information on system operation and status are sent to the MBB
processor by various sensors and optional boards that are located
at the unit. Access to the unit controls for configuration, setpoint
selection, schedule creation, and service can be done through a
unit-mounted scrolling marquee. Access can also be done
through the Carrier Comfort Network
®
(CCN) system using the
ComfortVIEW™ software, the accessory Navigator™ hand-
held display, or the System Pilot™ interface.
Table 1 — A Series Product Line
LEGEND
The
Comfort
Link system controls all aspects of the rooftop. It
controls the supply-fan motor, compressors, and economizers to
maintain the proper temperature conditions. The controls also
cycle or vary the speeds of the condenser fans to maintain suit-
able head pressure. All VAV units are equipped with a standard
VFD (variable frequency drive) for supply fan speed control and
supply duct pressure control. The
Comfort
Link controls adjust
the speed of the VFD based on a static pressure sensor input.
Constant volume (CV) units can be equipped with optional VFD
for staged air volume (SAV™) control. The indoor fan will oper-
ate at low speed for energy savings and high speed when re-
quired. In addition, the
Comfort
Link controls can raise or lower
the building pressure using multiple power exhaust fans con-
trolled from economizer damper position or from a building
pressure sensor. The control safeties are continuously monitored
to ensure safe operation under all conditions. Sensors include
suction pressure transducers, discharge pressure transducers, and
saturated condensing temperature sensors which allow for dis-
play of operational pressures and saturation temperatures.
A scheduling function, programmed by the user, controls the
unit occupied/unoccupied schedule. Up to 8 different schedules
can be programmed. The controls also allow the service person
to operate a quick test so that all the controlled components can
be checked for proper operation.
Conventions Used in This Manual
The following conventions for discussing configuration points
for the local display (scrolling marquee or Navigator accesso-
ry) will be used in this manual. Point names will be written with
the Mode name first, then any sub-modes, then the point name,
each separated by an arrow symbol (
). Names will also be
shown in bold and italics. As an example, the IAQ Economizer
Override Position which is located in the Configuration mode, In-
door Air Quality Configuration sub-mode, and the Air Quality
Setpoints sub-sub-mode, would be written as
Configuration
IAQ
IAQ.SP
IQ.O.P
.
A list of point names can be found in
Appendix A.
This path name will show the user how to navigate through the
local display to reach the desired configuration. The user
AVERTISSEMENT
RISQUE D´INCENDIE OU D´EXPLOSION
Si les consignes de sécurité ne sont pas suivies à la lettre,
cela peut entraîner la mort, de graves blessures ou des dom-
mages matériels.
Ne pas entreposer ni utiliser d´essence ni autres vapeurs ou
liquides inflammables à proximité de cet appareil ou de tout
autre appareil.
QUE FAIRE SI UNE ODEUR DE GAZ EST DÉTECTÉE
• Ne mettre en marche aucun appareil.
• Ne toucher aucun interrupteur électrique; ne pas
utiliser de téléphone dans le bâtiment.
• Quitter le bâtiment immédiatement.
• Appeler immédiatement le fournisseur de gaz en
utilisant le téléphone d´un voisin. Suivre les
instructions du fournisseur de gaz.
• Si le fournisseur de gaz n´est pas accessible, appeler le
service d´incendie.
L´installation et l´entretien doivent être effectués par un in-
stallateur ou une entreprise d´entretien qualifié, ou le four-
nisseur de gaz.
CAUTION
UNIT DAMAGE HAZARD
This unit uses a microprocessor-based electronic control
system.
Do not
use jumpers or other tools to short out com-
ponents or to bypass or otherwise depart from recommend-
ed procedures. Any short-to-ground of the control board or
accompanying wiring may destroy the electronic modules
or electrical components.
WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron
®
(R-410A) refrigerant systems operate at higher pres-
sures than standard R-22 systems. Do not use R-22 service
equipment or components on Puron refrigerant equipment.
UNIT
APPLICATION
48A2
CV Unit with Gas Heat, Vertical Supply
48A3
VAV Unit with Gas Heat, Vertical Supply
48A4
CV Unit with Gas Heat, Horizontal Supply
48A5
VAV Unit with Gas Heat, Horizontal Supply
48A6
CV Unit with Gas Heat, Vertical Supply with Greenspeed
®
Outdoor Fan
Control
48A7
VAV Unit with Gas Heat, Vertical Supply with Greenspeed Outdoor Fan
Control
48A8
CV Unit with Gas Heat, Horizontal Supply with Greenspeed Outdoor Fan
Control
48A9
VAV Unit with Gas Heat, Horizontal Supply with Greenspeed Outdoor Fan
Control
50A2
CV Unit with Optional Electric Heat, Vertical Supply
50A3
VAV Unit with Optional Electric Heat, Vertical Supply
50A4
CV Unit with Optional Electric Heat, Horizontal Supply
50A5
VAV Unit with Optional Electric Heat, Horizontal Supply
50A6
CV Unit with Optional Electric Heat, Vertical Supply with Greenspeed
Outdoor Fan Control
50A7
VAV Unit with Optional Electric Heat, Vertical Supply with Greenspeed
Outdoor Fan Control
50A8
CV Unit with Optional Electric Heat, Horizontal Supply with Greenspeed
Outdoor Fan Control
50A9
VAV Unit with Optional Electric Heat, Horizontal Supply with Greenspeed
Outdoor Fan Control
CV
—
Constant Volume
MCHX —
Microchannel Heat Exchanger
VAV
—
Variable Air Volume
Summary of Contents for WEATHERMAKER 48A2020
Page 112: ...112 Fig 20 Typical Main Control Box Wiring Schematic 48 50A Units ...
Page 113: ...113 Fig 21 Typical Auxiliary Control Box Wiring Schematic ...
Page 114: ...114 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown ...
Page 115: ...115 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown TO NEXT PAGE ...
Page 116: ...116 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont ...
Page 117: ...117 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown ...
Page 118: ...118 Fig 25 Typical Controls Option Wiring Schematic SW1 SW2 OR DEHUMIDIFY SWITCH ...
Page 119: ...119 Fig 26 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown ...
Page 120: ...120 Fig 27 Typical Power Schematic of Greenspeed Low Ambient Option 48 50A 060 Unit Shown ...
Page 121: ...121 Fig 28 Typical Small Chassis Component Location Size 020 035 Units ...
Page 122: ...122 Fig 29 Typical Large Chassis Component Locations Size 040 060 Units ...
Page 185: ...185 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...