TM 9-4120-360-14
DIRECT SUPPORT MAINTENANCE INSTRUCTIONS
Section I CONTROL PANEL
Description (See fIgure 5-1).
5.1.
The control panel assembly is mounted on top of the junction box behind the lower panel. It Contains the three controls by
means of which all functions of the air conditioner are controlled. These controls comprise the following:
a. Mode Selector Switch This is a five-position rotary switch consisting of four "wafers" or individual
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five-position elements. Each position of the switch connects various functional units in each mode of operation.
b. Temperature Control Thermostat This thermostat is set at the desired temperature level to heat or cool the
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conditioned area in accordance with a feedback signal from a sensing bulb which causes the switch to open or close on
temperature rise or temperature drop.
c. Two-speed Fan Switch. This two-position switch connects or disconnects an auxiliary set of windings in the
evaporator/condenser fan motor. When connected, these windings double the speed of the motor from 1725 to 3450 rpm.
thereby increasing airflow.
Removal
5.2.
WARNING
Disconnect power from the air conditioner before performing maintenance on the electrical syste64m.
The voltage used can be lethal.
Remove the control panel assembly from the air conditioner in accordance with the following instructions.
a. Unscrew two panel fastener screws from the top edge of the lower panel, and remove the panel.
b. Unscrew and disconnect the electrical connector plug from the receptacle on the left end of the control panel
housing.
c. Disconnect the evaporator air intake grille by turning six can-lock studs in the frame a quarter-tum
counter-clockwise. Remove the grille. Remove the air filter by unscrewing two screws in the retaining strip. Remove the
strip and pull out the filter.
d. Remove one screw from the loop clamp holding the thermostat sensor bulb.
e. Remove four screws from the comers of the control panel mounting flange, and carefully withdraw the
control panel assembly while leading the sensor bulb and its associated capillary tube through the grommet hole to
remove it. Coil the capillary tube without kinking.
5.3.
Disassembly
Disassemble the control panel only to the extent required for repair or replacement. Proceed as directed in the following
steps:
a. Pull the knobs off the mode selector switch and the temperature control thermostat.
