Safety Considerations; General; Basic Control Usage; Comfortlink Control - Carrier 48PG20 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

CONTENTS (cont)
• ENTHALPY SENSORS
• RETURN/SUPPLY AIR TEMPERATURE SENSOR
• SPACE HUMIDITY SENSOR
• ELECTRIC HEAT
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85-92
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Manual Outdoor Air Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Economizer Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Evaporator Fan Service and Replacement. . . . . . . . . . . . . . . . .87
Evaporator Fan Performance Adjustment . . . . . . . . . . . . . . . . .87
Evaporator Fan Belt Tension Adjustment . . . . . . . . . . . . . . . . .88
Condenser-Fan Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Verify Sensor Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Economizer Operation During Power Failure . . . . . . . . . . . . . .88
Evacuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Refrigerant Charge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Gas Valve Adjustment (48PG Only) . . . . . . . . . . . . . . . . . . . . . . .90
High Altitude (48PG Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
Main Burners (48PG Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Protective Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Relief Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Control Circuit 24-V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Diagnostic LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
APPENDIX A - LOCAL DISPLAY AND
CCN TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93-103
APPENDIX B - CONTROL MODES WITH
HUMIDI-MIZER SYSTEM AND ECONOMIZER. . . . . . . . . . 104
CONTROL SET UP POINT AND
CONFIGURATION LOG. . . . . . . . . . . . . . . . . . . . . . . . CL-1 to CL-5
UNIT START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . CL-6

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can
be hazardous due to system pressure and electrical compo-
nents. 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 pre-
cautions 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 avail-
able for all brazing operations.
Before performing service or maintenance operation on
unit turn off and lock off main power switch to unit.
Electrical shock can cause personal injury and death.
Shut off all power to this equipment during installation
and service. The unit may have an internal non-fused
disconnect or a field-installed disconnect.
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 recom-
mended procedures. Any short-to-ground of the control
board or accompanying wiring may destroy the electronic
modules or electrical components.
Page
1. 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.
2. 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 neigh-
bor's phone. Follow the gas supplier's instructions.
4. If you cannot reach your gas supplier call the fire
department.
This publication contains Start-Up, Controls, Operation,
Service, and Troubleshooting information for the 48/50PG
rooftop units. See Table 1. These units are equipped with
ComfortLink™ controls and use Puron® refrigerant.
Table 1 - Unit Sizes (48/50PG)
UNIT
48/50PG20
48/50PG24
48/50PG28

BASIC CONTROL USAGE

ComfortLink Control -

comprehensive unit-management system. The control system
is easy to access, configure, diagnose and troubleshoot.
The ComfortLink™ control is fully communicating and
cable-ready for connection to the Carrier Comfort Network®
(CCN) building management system. The control provides
high-speed communications for remote monitoring via the
Internet. Multiple units can be linked together (and to other
ComfortLink control equipped units) using a 3-wire communi-
cation bus.
The ComfortLink control system is easy to access through
the use of a unit-mounted display module. There is no need to
bring a separate computer to this unit for start-up. Access to
control menus is simplified by the ability to quickly select from
11 menus. A scrolling readout provides detailed explanations
of control information. Only four, large, easy-to-use buttons are
required to maneuver through the entire controls menu. The
display readout is designed to be visible even in bright sunlight.
For added service flexibility, an accessory hand-held
Navigator™ module is also available. This portable device has
an extended communication cable that can be plugged into the
unit's communication network at the main control box. The
Navigator display provides the same menu structure, control
access and display data as is available at the unit-mounted
Scrolling Marquee display.
2

GENERAL

NOMINAL TONS
18
20
25
The ComfortLink control is a