Carrier 38TN Service Manual Download

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4. Disconnect fan motor wires and cut wire ties. Remove wires

from control box. Refer to unit wiring label.

5. Remove screws holding top cover to coil grille and corner

posts.

6. Lift top cover from unit.

7. Reverse sequence for reassembly.

Step 2—Remove Fan Motor Assembly

1. Perform items 1 through 6 above.

2. Remove nuts holding fan motor top cover.

3. Remove motor and fan blade assembly.

4. Reverse sequence for reassembly.

5. Prior to applying power, check that fan rotates freely.

Step 3—Information Plate

The information plate is secured to the front of the control box and
provides the control box cover. (See Fig. 3.) This plate also
provides a surface to attach the wiring schematic, superheat
charging tables with instructions, and warning labels. The plate has
2 tabs on the top edge that are bent down at slightly more than 90°.
When the information plate is removed, these tabs can be inserted
into 2 mating slots in the bottom front edge of the control box and
the plate will hang down forming a lower front panel. (See Fig. 4.)
This is convenient when access to the controls is required while the
unit is operating. The information plate on the small size casing
completely covers the opening below the control box. On larger
models the information plate may not cover the entire opening. In
this instance, the top cover can be removed and placed on its side
to cover the additional space.

ELECTRICAL

Exercise extreme caution when working on any electrical
components. Shut off all power to system prior to trouble-
shooting. Some troubleshooting techniques require power to
remain on. In these instances, exercise extreme caution to
avoid danger of electrical shock. ONLY TRAINED SER-
VICE PERSONNEL SHOULD PERFORM ELECTRICAL
TROUBLESHOOTING.

Troubleshooting chart for the 38TN Air Conditioner units is
provided at the back of this manual. It will enable the service
technician to use a systematic approach to locating the cause of a
problem and correcting system malfunctions. (See Fig. 21.)

Step 1—Aluminum Wire

Aluminum wire may be used in the branch circuit (such as the
circuit between the main and unit disconnect), but only
copper wire may be used between the unit disconnect and the
unit.

Whenever aluminum wire is used in the branch circuit wiring with
this unit, adhere to the following recommendations.

Connections must be made in accordance with the National
Electrical Code (NEC), using connectors approved for aluminum
wire. The connectors must be UL approved (marked Al/Cu with
the UL symbol) for the application and wire size. The wire size
selected must have a current capacity not less than that of the
copper wire specified, and must not create a voltage drop between
the service panel and the unit in excess of 2 percent of the unit
rated voltage. To prepare the wire before installing the connector,
all aluminum wire must be "brush-scratched" and coated with a
corrosion inhibiter such as Pentrox A. When it is suspected that the
connection will be exposed to moisture, it is very important to
cover the entire connection completely to prevent an electrochemi-
cal action that will cause the connection to fail very quickly. Do
not reduce the effective size of wire, such as cutting off strands so
that the wire will fit a connector. Proper size connectors should be

Fig. 2—Basic Cabinet Design

A92446

Fig. 3—Information Plate

A88411

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