Specifications
CONTENTS (cont)
Page
ENTHALPY SENSORS
RETURN/SUPPLY AIR TEMPERATURE SENSOR
SPA(E 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 (48PC Only) ....................... 90
High Altitude (48PC Only) ................................. 9O
Main Burners (48PC 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 ........................ (L-1 to (L-5
UNIT START-UP CHECKLIST ........................... (L-6
SAFETY CONSIDERATIONS
Installation and sea;icing of air-conditioning equipmem can
be hazardous due to system pressure and electrical compo-
nents. Only trained and qualified service personnel should
install, repair, or service air-conditioning equiplnent. Untrained
personnel can perform the basic maintenance functions of
replacing filters. Trained service personnel should perform all
other operations.
When working on air-coMitioning 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 extinmlishers 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 fiom recom-
mended procedures. Any short-to-mound of the control
board or accompanying wiring may destroy the electronic
modules or electrical components.
1. hnproper installation, adjusnnent, alteration, service,
or maintenance can cause property damage, personal
injury, or loss of lii_. Refer to the User's Information
Manual provided with this unit for lnore details.
2. Do not store or use gasoline or other flmmnable
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 tiom a neigh-
bor's phone. Follow the gas supplier's instructions.
4. It"you cannot reach your gas supplier call the fire
department.
GENERAL
This publication contains Start-Up, Controls, Operation,
Service, and Troubleshooting intbnnation for the 48/50PG
rooftop units. See Table 1. These units are equipped with
('ol_/brtLink TM controls and use Purona)reiiigerant.
Table 1 -- Unit Sizes (48/50PG)
UNIT NOMINAL TONS
48/50PG20 18
48/50PG24 20
48/50PG28 25
BASIC CONTROLUSAGE
ComfortLink Control -- The Col_/brtLink control is a
colnprehensive unlt-lnanagement system. The control system
is easy to access, configure, diagnose and troubleshoot.
The ComJbrtLink TM control is fully colnmunlcating and
cable-ready for connection to the Carrier Colnfort NetworkS,R)
(CCN) building managelnent system. The control provides
high-speed colnlnunlcations for remote monitoring via the
Intemet. Multiple units can be linked together (and to other
('omJbrtLink control equipped units) using a 3-wire colrnnuni-
cation bus.
The ComJbrtLink control system is easy to access through
the use of a unit-lnounted display module. There is no need to
bring a separate computer to this unit tbr start-up. Access to
control menus is simplified by the ability to quickly select fiom
11 menus. A scrolling readout provides detailed explanations
of control int;)nnation. Only tour, large, easy-to-use buttons are
required to maneuver through the entire controls menu. The
display readout is designed to be visible even in bri_lt sunlight.
For added service flexibility, an accessory hand-held
Navigator TM 1nodule is also available. This portable device has
an exteMed colmnunlcation cable that can be plugged into the
unit's colmnunication network at the main control box. The
Navigator display provides the stone menu structure, control
access and display data as is available at the unit-mounted
Scrolling Marquee display.