Buick LeSabre 1965 Service Manual page 782

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-AIR CONDITIONER
TEMPERATURE CONTROL LEVER
-VACUUM MODULATOR CONTROLS VACUUM TO
STV VACUUM DIAPHRAGM (VACUUM IS 0 AT
MAX. COOLING: AND 6 TO 7 INCHES AT
CAPILLARY TUBE
COMPRESSOR
COMPRESSES THE LOW
PRESSURE REFRIGERANT
TO A HCH PRESSURE.
-DISCHARGE
LINE
S T V VACUUM DIAPHRAGM SETS VALVE —^
TO INCREASE EVAPORATOR PRESSURE
(DECREASE COOLING) WHEN VACUUM
PRESENT AT DIAPHRAGM, MINUMIN
COOLING OBTAINED WHEN 6 TO 7 INCHES
OF VACUUM IS PRESENT. MAXIMUM
COOLING OBTAINED WHEN THERE IS NO
VACUUM PRESENT AT DIAPHRAGM.
AIR PASSING OVER CONDENSER REMOVES
HEAT FROM HIGH PRESSURE GAS WHICH
, CONDENSES T O A L I Q U I D .
qs
EVAPORATOR
AIR R4SSING OVER EVAPORATOR
LOSES HEAT TO LOW PRESSURE
LIQUID WHICH EVAPORATES TO A
GAS ALSO, AIR LOSES MOISTURE
TO THE COLD SURFACE OF THE
EVAPORATOR.
SUCTION THROTTLE VALVE (STV)
AUTOMATICALLY MAINTAINS EVAPORATOR
PRESSURE! EVAPORATOR OUTLET AIR
TEMPERATURE) AND PREVENTS EVAPORATOR
CORE FREEZE - U P .
\ \
1
• y '
!
' V ^ t-fi-t-t-r - -;•!
m
RECEIVER DEHYDRATOR v
RECEIVER ACTS AS A RESERVOIR TO ^
FURNISH A SOLID COLUMN OF LIQUID
TO EXPANSION VALVE DEHYDRATOR
FILTER ABSORBS MOISTURE AND
TRAPS FOREIGN MATERIAL PRESENT
IN SYSTEM.
p-r -rr-r ? l-h-i t 1 I ft T t f l - T t f I i f\
lU- !
N
, ,||>,, .A44-JX |-U>?J
•EXPANSION VALVE
-SIGHT GLASS
USED AS SYSTEM
DIAGN09SAID TO
DETERMINE REFRIGERANT
SHORTAGE.
AUTOMATICALLY CONTROLS
REFRIGERANT FLOW INTO
EVAPORATOR. THE VALVE'S
PRESSURIZED BULB CONTROLS
THE OPENING OF THE VALVE TO
MAINTAIN HIGHER REFRIGERANT
TEMPERATURE AT EVAPORATOR OUTLET
TO INSURE REFRIGERANT REMAINS IN
EVAPORATOR LONG ENOUGH TO
COMPLETELY VAPORIZE ANO
REMOVE HEAT FROM AIR.
• PRESSURE EQUALIZER LINE
THE EXPANSION VALVE'S PRESSURE
EQUALIZER LINE PERMITS S T V
OUTLET PRESSURE TO BE
IMPOSED ON THE VALVE'S
DIAPHRAM TO PREVENT THE S T V
OUTLET PRESSURE FROM DROPPING
BELOW A PREDETERMINED PRESSURE.
(WHEN THE COMPRESSOR CAPACITY
BECOMES GREATER THAN
EVAPORATOR LOAD, THE DROP IN THE
S T V OUTLET PRESSURE FORCES THE
EXPANSION VALVE TO FLOOD LIQUID
THROUGH EVAPORATOR ANO INCREASE
EVWORATOR OUTLET PRESSURE)
HIGH PRESSURE GAS
HIGH PRESSURE LIQUID
LOW PRESSURE LIQUID
LOW PRESSURE GAS-EVAPORATOR OUTLET
LOW PRESSURE G A S - S T V OUTLET
(COMPRESSOR SUCTION)
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Figure 11-59—Air Conditioner Refrigerant Circuit - 49000 Series