38TN
Air Conditioner with R134A Refrigerant
Application Guideline
and Service Manual
SAFETY CONSIDERATIONS
Service and repair of these units should be attempted only by
trained service technicians familiar with Carrier standard service
instruction and training material.
All equipment should be installed in accordance with accepted
practices and unit Installation Instructions, and in compliance with
all national and local codes.
Power should be turned off when servicing or repairing electrical
components. Extreme caution should be observed when trouble-
shooting electrical components with power on. Observe all warn-
ing notices posted on equipment and in instructions or manuals.
Refrigeration system contains refrigerant under pressure. Extreme
caution should be observed when handling refrigerants. Wear
safety glasses and gloves to prevent personal injury. During
normal system operation, some components are hot and can cause
burns. Rotating fan blades can cause personal injury. Appropriate
safety considerations are posted throughout this manual where
potentially dangerous techniques are addressed.
INTRODUCTION
This Application Guideline and Service Manual provides the
required system information necessary to install equipment in
low-ambient conditions, and service, repair, and maintain the
family of 38TN Air Conditioners with nominal capacities ranging
from 24,000 to 48,000 Btu’s. These air conditioners use R134A
refrigerant and operate at lower pressures than standard R22
systems.
TABLE OF CONTENTS
Page
SECTION 1—INSTALLATION GUIDELINE ......................1
SECTION 2—LOW-AMBIENT GUIDELINE ......................1
•
Applicable Systems
•
Field-Installed Accessories
•
Accessory Information
SECTION 3—SERVICE MANUAL ........................................3
UNIT IDENTIFICATION .........................................................3
•
Product Number Stamped on Unit Rating Plate
•
Serial Number Identification
CABINET ....................................................................................3
•
Remove Top Cover
•
Remove Fan Motor Assembly
•
Information Plate
ELECTRICAL ............................................................................4
•
Aluminum Wire
•
Contactor
•
Capacitor
•
PTC Devices
•
Cycle Protector
•
Crankcase Heater
•
Time-Delay Relay (TDR)
•
Pressure Switches
•
Fan Motor
•
Compressor Plug
•
Low-Voltage Terminals
MILLENNIUM SCROLL COMPRESSOR ............................9
•
Mechanical Failures
•
Electrical Failures
•
System Clean-Up After Burnout
•
Compressor Removal and Replacement
REFRIGERATION SYSTEM ................................................11
•
Refrigeration Cycle
•
Leak Detection
•
Brazing
•
Service Valves
•
AccuRater® (Bypass Type) Components
•
Thermostatic Expansion Valve (TXV)
•
Coil Removal
•
Accumulator
•
Contaminant Removal
•
R134A Refrigerant System Charging
•
Checking Charge
•
Care and Maintenance
TROUBLESHOOTING CHART ...........................................18
SECTION 1—INSTALLATION GUIDELINE
Specifications for this unit in the RNC market require the outdoor
section, indoor section, refrigerant tubing sets, metering device,
and filter drier listed in Product Data Digest (PDD.) There can be
no deviation.
Specifications for this unit in the AOR market require change-out
of the total system, including the outdoor section, indoor section,
refrigerant tubing sets, metering device, and filter drier listed in
PDD. There can be no deviation.
The system can be applied in low-ambient conditions when
installed following the guidelines in Section 2 of this manual.
For long-line applications over 50 ft, consult the 38TN (R134A)
Residential Application Bulletin available from your local dis-
tributor. The R134A long-line application differs from R22 long-
line application.
SECTION 2—LOW-AMBIENT GUIDELINE
This guideline is for 38TN split-system products only. For
applications involving standard R22 single-speed products, refer to
Low-Ambient Guideline Residential Split-System Application
Bulletin.
This guideline explains the system changes and accessories re-
quired for any 38TN application having operating requirements
below 55°F outdoor ambient temperatures.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
1
2
Tab
3a 5a 1a
PC 101
Catalog No. 513-829
Printed in U.S.A.
Form 38TN-1XA
Pg 1
3-94
Replaces: New
Summary of Contents for 38TN
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