TM9-4120-360-14
(7) Pressure Cutout Switches
(8) Sight-glass Liquid Indicator
(9) Circuit Breaker
b. Special Features
Remote Control Capability
1.5.
Location and Description of Major Components (see figure 1-2)
Compressor (1). It consists of a reciprocating compressor driven by an electric motor, hermetically sealed into a steel
container with a lifetime charge of oil. A crankcase heater surrounds the lower part of the container. The heater is
thermostatically controlled to prevent migration of liquid refrigerant into the crankcase where it would become mixed with
the oil.
Evaporator Coil (2). Is made up of interconnected parallel copper tubes retained in a series of multiple, closely spaced
aluminum fins. Each end of the coil is enclosed and supported by a steed plate, which provides the means for mounting the
coil in the air conditioner. and for supporting the mist eliminator.
Evaporator Condenser Fans (4). The evaporator fan impeller is centrifugal, and the condenser fan impeller is of the axial
type.
Solenoid Values. There are two solenoid valves. The liquid line solenoid valve, which closes the line to the evaporator coil
when energized, is located in the lower chamber of the air conditioner, to the right of and behind the compressor. The
pressure equalizer solenoid valve is located at the top rear portion of the air conditioner.
Expansion Values. The valve controlling refrigerant flow to the evaporator coil, is located behind the evaporator coil, and
can be identified by the three distribution lines that connect it to the coil. The quench line expansion valve is located near the
back wall in the upper part of the air conditioner.
Pressure Cutout Switches (5). They are both manually reset limit switches, and are connected through capillary tubes to the
discharge and suction lines of the refrigeration system. If refrigerant pressure falls below the minimum set for the
low-pressure cutout switch, or the pressure exceeds the maximum set for the high-pressure switch. the electrical connection
through the compressor relay is opened to stop the compressor.
Control Panel (6). Contains the following electrical controls; fan speed switch, thermostat and mode selector switch.
Fresh Air Damper Control (7). Is a bead chain that connects to a spring loaded door that controls fresh air intake, Lift chain
and pull to close fresh air door.
Sight-glass Liquid Indicator (8). The condition of liquid refrigerant flowing through the system can he observed through this
window when the compressor is operating in the cooling mode. A small data plate below the sighglass displays three colors
for comparison with that of the refrigerant; green. chartreuse and yellow. Green indicates that the refrigerant contains no
moisture. Chartreuse and yellow indicate the presence of moisture, and the need to replace the filter-drier and refrigerant. A
milky or bubbly appearance of the refrigerant indicates that the system contains insufficient refrigerant, and that more must
be added.
Circuit Breaker Reset Knob (9). The circuit breaker controls power to the air conditioner. A push-pull flexible cable
connects the circuit breaker to the control knob.
