TM 9-4120-357-14
(2) Slide the core end fitting (14) over the cable core, and secure it temporarily by tightening the setscrew.
Loosely attach the hold-down clamp (16) with two screws and lock washers.
(3) Install the control panel assembly on the top mounting flanges, and secure with four screws.
(4) Secure the junction box in position with six screws (7, figure 4-3) through the casing into the side mounting
flange, and two screws (8) and washers (9) into the lower right-hand bracket.
(5) Adjust the circuit breaker cable as required, and tighten screws, clearance between the core end fitting (14)
and the actuator arm hole (16) should be 0.12-0.25 inch (3-6 mm).
(7) Connect wiring harness plugs to their associated receptacles on junction box. Connect power supply to the
air conditioner, and check operation.
(8) Place the cover assembly (a, figure 4-3) on junction box, and secure with four panel fastener screws (1).
(9) Position the front access panel on the air conditioner by inserting its lower edge behind the step in the front
of the base plate. Push the panel into position, and secure it with four panel fastener screws.
Section X. MAINTENANCE OF COMPRESSOR ASSEMBLY
4-33. General.
The compressor assembly is a hermetically sealed unit containing the compressor, drive motor and thermostatic over-
load switch, and a lifetime charge of oil. The compressor assembly is equipped with a thermostatically-controlled crank-
case heater, which maintains a temperature in the crankcase above the boiling point of refrigerant R-22. By this means,
migration of refrigerant into the compressor, and liquefaction of refrigerant inside the compressor is prevented. Liquid
Refrigerant, being incompressible, would seriously damage the compressor during start-up and operation. Because the
compressor is a sealed unit, internal repairs cannot be made; if faulty, the unit must be replaced. However, the crank-
case heater and thermostat can be replaced, since they are mounted externally.
a. Testing. Test the compressor assembly as indicated in the following procedure: (See figure 4-12.)
(1) Unscrew four panel fastener screws from the front access panel, and remove the panel.
WARNING
Disconnect the power supply before performing maintenance work on the air
conditioner. The voltage used can be lethal.
(2) Disconnect electrical plug, P11, from the receptacle on the side of the compressor (3), remove the compres-
sor junction box cover (4, figure 4-12) by removing wing nut and washers.
(3) Remove electrical receptacle, J11, (6) from the flange of the compressor junction box by removing four
screws, nuts and washers.
NOTE
The compressor crankcase heater is controlled by a thermostat (9, figure 4-12).
Therefore, the following continuity check must be made when the compressor is
cold enough to close the contacts of the thermostat. If necessary, apply a plastic
bag of dry ice to the area of the thermostat well for a few minutes before checking
continuity of G-H.
(4) Using an ohmmeter or continuity tester, check continuity of points G-H (crankcase heater) and A-B (thermal
overload switch). Check continuity of points D-E, E-F, and F-D. All of the foregoing should show continuity. Check to
be sure that no continuity exists between points A, B, D, E, F, G and H and compressor housing or common ground. If
continuity is not indicated at points G-H, or if continuity from G or H to ground is indicated, replace the crankcase heater
and thermostat. If continuity is not indicated between point D-E, E-F, or F-D, or if continuity is indicated between D, E,
and F and ground, report the trouble to direct support maintenance.
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