Section VI. UNIT MAINTENANCE PROCEDURES.
3-17. ELECTRICAL WIRING REPAIR GENERAL. This section contains the maintenance procedures authorized for the
Unit maintenance as defined in the Maintenance Allocation Chart located in Appendix B. Before performing any
procedure in this section, use the Unit Troubleshooting procedures to identify and locate the parts on the air conditioner
unit requiring maintenance. Preferred repair methods consist of replacing wires, terminals, connectors, etc., rather than
splicing wires, bending ends to form terminals, and other make-shift procedures, although the latter may be appropriate
for emergency field repairs. Determine the proper size and length of wire, or the terminal or connect or to be used for
proper precautions. Avoid burns and possible eye damage from splattering by
wearing thermal gloves and protective goggles or face shield. Do not solder or
braze in the presence of flammable materials. Remove nearby combustible
materials to shield them from heat source. Solder, brazing alloys, and flux contain
materials which are hazardous to health. Avoid breathing vapors or fumes from
soldering or brazing operations. Perform operations only in properly ventilated
areas. Wash hands with soap and water after handling solder, brazing alloys, and
a. Soldering Connections
. Wire connections must
be made mechanically sound before they are soldered; solder
alone dots not provide sufficient strength to prevent breakage. Joining surfaces of connections to be soldered must be
clean and bright. If a separate flux is used, it should conform to soldering flux (Item 6, Appendix E) and should be
brushed onto the joint before soldering. If an uncored solder is used, it should be a lead-tin solder, (Item 1, Appendix E).
Wires should always be heated to the point at which the solder will melt completely and flow into all parts of the joint.
Excessive build-up solder "gobs" on the joint should be avoided or removed.
b. Insulation Joints. The preferredmethodofinsulatingelectricaljointsisbytheuseofheat-shrink tubing, To apply, cut a
piece of heat-shrink tubing (Item 17, Appendix E) of suitable diameter to a one-inch length for covering joints at terminals
or connectors, or to a length about 1/2 inch (1.3 cm) longer than the joint to be insulated, and slide the tubing over the
wire before making the joint. After the joint is made, slide the tubing so that it covers the joint, and shrink in place with
c. Splicing Wires. To repair broken or cut wires that arc otherwise sound, the mating ends can be stripped and
spliced. A commercial butt splice can be crimped onto the end to join them, or a: Western Union wire splice can be
The latter is made by stripping 1/4 to 1/2 inch (0.6 to 1.3 cm) of insulation from the wire ends,
holdingtheendsparallelandfacingoppositedirectionsthentwistingeachendaround the other wire at least three turns. Solder
and apply insulation as described above.
d. Crimping Terminals To install a terminal on the end of a wire, strip 1/4 to 1/2 inch (0.6 to 1.3 cm) of insulation
from the end of the wire, apply a one-inch piece of heat-shrink tubing (if the terminals are of the uninsulated type), and
insert wire end into the shank of the terminal. Crimp the shank, and install heat shrink tubing, if necessary.