Carrier 38TN, Service Manual

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• Evaporator Freeze Thermostat
• Winter Start Control
• Wind Baffle
• Start Components
• Ball Bearing Motor
Step 3—Accessory Information
LOW-AMBIENT CONTROLLER — Required on all applica-
tions. There are 2 low-ambient controllers available from RCD.
32LT660004 Motor Master: Used on 208/230-v systems.
Requires ball bearing motor.
P251-0083
Solid-State Head Pressure Control:
Requires ball bearing motor in full modulation mode
only. See Installation Instructions for set-up on sleeve
bearing motor application.
COMPRESSOR CRANKCASE HEATER — Required on all ap-
plications. The crankcase heater is purchased from Finished
Goods. See PDD for accessory part no.
EVAPORATOR FREEZE THERMOSTAT — Required on all
applications. The evaporator freeze thermostat is purchased from
Finished Goods. See PDD for accessory part no.
WINTER START CONTROL — Required on all applications
which have factory-supplied or field-installed low-pressure switch.
The winter start control is purchased from Finished Goods. See
PDD for accessory part no.
WIND BAFFLE — Use only on installations where high prevail-
ing winds are prevalent and where outdoor ambient temperatures
of less than 0°F could occur during unit operation. Wind baffles
are field fabricated. For construction details see Fig. 1.
START COMPONENTS — The 38TN unit is equipped with a
Millennium scroll compressor specifically designed for use with
R134A refrigerant. A PTC soft start assist is factory installed. No
other start assist is required.
BALL BEARING MOTOR — Required on all applications using
motor master controller and solid state head pressure control when
used in full modulation mode. The 024 through 036 sizes require
motor HC38GE230, and the 048 size requires motor HC40GE230.
SECTION 3—SERVICE MANUAL
SAFETY CONSIDERATIONS
Service and repair of these units should be attempted only by
trained service technicians familiar with Carrier standard service
instructions and training material.
All equipment should be installed in accordance with accepted
practices, 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 service manual enables a service technician to service, repair,
and maintain the family of 38TN Air Conditioners.
Improper installation, adjustment, alteration, service, mainte-
nance, or use can cause explosion, fire, electrical shock, or
other conditions which may cause personal injury, death, or
property damage. Consult a qualified installer, service agency
or your distributor or branch for information or assistance.
The qualified installer or agency must use factory-authorized
kits or accessories when modifying this product.
UNIT IDENTIFICATION
Step 1—Product Number Stamped on Unit Rating Plate
The unit product number has 16 positions containing groups of
numbers, letters, and dashes that indicate specific information
about the unit. Listed below is the breakdown of the 16 positions.
Positions 1 and 2 —Type of Product
Example: 38 — Split-System Air Conditioner or Heat Pump
Positions 3, 4, and 5—Model Letters
Identifies a specific product model. In some instances the fifth
position will be a dash (-).
Position 6, 7, and 8—Nominal Cooling Capacity (in thousands
Btuh)
Example: 036 = 36,000 Btuh or 3-ton capacity.
Position 9, 10, and 11—Not Used
These positions will contain dashes (---).
Position 12—Electrical Supply
3 = 230 or 208-230 or 208/230, 1 Phase, 60 Hertz
Position 13—Series
New units have 0. As major component variations occur, such as
compressor, fan motor, coil circuiting changes, etc., the change is
indicated by increasing this digit in increments of 1.
Position 14—Packaging
On split-system products, this digit will be 0.
Positions 15 and 16—Not Used
These positions will contain dashes (--).
Step 2—Serial Number Identification
The unit serial number has 10 positions containing groups of
numbers and a letter that indicates specific information about the
unit. Listed below is the breakdown of the 10 positions.
Positions 1 and 2—Week of Manufacture
Example:
01—First week of a year
52—Last week of a year
Positions 3 and 4—Year of Manufacture
Example:
94—1994
Position 5—Manufacturing Site
Example:
E—Collierville
Positions 6 through 10—Serial Number
CABINET
Certain maintenance routines and repairs require removal of
cabinet panels. (See Fig. 2.)
Step 1—Remove Top Cover
1. Turn off all power to outdoor and indoor units.
2. Remove access panel.
3. Remove information plate.
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