Buick LeSabre 1965 Service Manual page 773

1 1 - 4 0 OPTIONAL HEATER-AIR CONDITIONER SYSTEM ACCESSORIES
rubber hose with double cord re-
inforcements. The hose ends are
fitted with O-ring fittings.
2. Schrader Service Valves. Two
Schrader service valves are used
on the air conditioner for evac-
uating and charging the system.
The valve located on the com-
pressor discharge line at rear of
compressor, also is used for
checking compressor head or dis-
charge pressures. The low pres-
sure valve located on the suction
throttle valve is also used for
c h e c k i n g evaporator pressure
when functional testing system or
adjusting suction throttle valve.
3. Condenser. The condenser is
similar to the ordinary car radi-
ator but is designed to withstand
much higher pressures. The con-
denser used on all series is of
aluminum construction. The con-
denser is mounted in front of the
radiator so that it receives a high
volume of air. Air passing over
the condenser cools the hot high
pressure refrigerant gas, causing
it to condense into high pressure
liquid refrigerant.
4. Receiver-Dehydrator. The re-
ceiver-dehydrator is located at
the right front of engine com-
partment. A liquid indicator or
sight glass is an integral part of
the outlet pipe of the receiver-
dehydrator. The sight g l a s s
serves as an aid to diagnosis.
The appearance of bubbles or
foam beneath the sight glass when
ambient temperature is higher
than 70°F indicates a i r or a
shortage of refrigerant in the
system.
CAUTION: Continuous bubbles
may appear in a properly charged
system on a cool day. This may
be considered normal if tempera-
ture of surrounding air is low.
The purpose of the receiver part
of assembly is to insure a solid
column of liquid refrigerant to the
expansion valve at all times, pro-
vided the system is properly
charged. The dehydrator part of
DIAPHRAGM
DISC
FILTER
SCREEN
INLET
VALVE VALVE
NYLON VALVE
INSERT
CAPILLARY
TUBE
OPERATING
PIN
OPERATING
DIAPHRAGM EQUALIZER LINE
ADJUSTING NUT
JUSTING SPRING WASHER
TOSTV
OUTLET
Figure 11-50—Expansion Valve
assembly functions to absorb any
moisture that might be present
in system after assembly. Also,
it traps foreign material which
may have entered system during
assembly.
NOTE: IN and OUT are stamped
on receiver. IN attaches to con-
denser and OUT to liquid line.
5. Expansion Valve. The expan-
sion valve is located at the inlet
to the evaporator core.
The expansion valve consists of
a capillary bulb and tube which
is connected to an operating dia-
phgram sealed within the valve
itself, and an equalizer line which
connects the valve with the suc-
tion throttling valve outlet pres-
sure. See Figure 11-50.
The valve contains three opera-
ting pins, valve stationary seat,
valve, valve carriage, adjusting
spring and screw, an inlet which
has a fine mesh screen, and an
outlet connection (which attaches
to the evaporator). The fine mesh
screen at the inlet of the valve
provides protection to the valve
by preventing dirt and other for-
eign material from entering the
valve.
While this valve is located at the
inlet of the evaporator, the
thermo bulb is attached to the
evaporator outlet pipe.
The equalizer line joins the ex-
pansion v a l v e to the suction
throttle valve outlet so that this
pressure will register in the ex-
pansion valve.
The purpose of the expansion
valve is to regulate the flow of
liquid refrigerant into the evapo-
rator automatically in accordance
to the r e q u i r e m e n t s of the
evaporator.
This valve is the dividing point
in the system between high pres-
sure liquid refrigerant supplied
from the receiver and relatively
low pressure liquid and gaseous
refrigerant in the evaporator. It
is so designed that the tempera-
ture of the refrigerant at the
evaporator outlet must have 6°F.
of superheat before more refrig-
erant is allowed to e n t e r the
evaporator. Superheat is an in-
crease in temperature of the
gaseous refrigerant above the
temperature at which the refrig-
erant vaporized.