Air Conditioning - Jeep 1979 CJ-5 Technical & Service Manual

3E-1
M E
CONDITIONING
SECTION INDEX
Cherokee-Wagoneer-Truck Models
3E-25
CJ Models
3E-22
General Information 3E-1
Pag®
General Service Procedures
3E-2
Tools
3E 21
G E N E R A L I N F O R M A T I O N
Pl|l
System Components
3E-1
P i l l
System Operation
31-1
SYSTEM COMPONENTS
Compressor—The compressor is a two-cylinder, belt-
driven pump used to circulate and increase the pressure
of the refrigerant in the system.
Condenser—The condenser is mounted in front of the
radiator to allow air to flow over the cooling fins and
remove heat from the refrigerant. As the refrigerant
passes through the condenser, it liquifies (condenses).
Receiver/Drier—The receiver/drier is a reservoir
used to store the precise amount of refrigerant required
by the system. The refrigerant level in the receiv-
er/drier, must be adequate to provide a steady flow of
refrigerant to the expansion valve. The receiver/drier
contains a desiccant to remove moisture from the sys-
tem. The receiver/drier must be replaced anytime the
system has been open to atmosphere due to a system
component failure. If the charge is lost, the receiv-
er/drier opening should be tightly capped immediately.
Expansion Valve—The thermostatic expansion valve
is located at the inlet of the evaporator. It meters the
refrigerant to the evaporator to maintain proper flow
for the various evaporator heat load requirements en-
countered during operation. The metering action of the
expansion valve is controlled by the temperature sen-
sing bulb mounted on the outlet (suction) line of the
evaporator.
Evaporator—The evaporator is an air cooler and
dehumidifier. As the refrigerant enters the evaporator
core, it begins to boil. The heat in the air passing over
the evaporator transfers or gives up its heat to the
boiling refrigerant. As the air cools, the moisture in the
air condenses on the evaporator core and is drained off
as water.
SYSTEM OPERATION
The compressor increases the pressure and temper-
ature of the system refrigerant (fig. 3E-1). The heated
refrigerant vapor is then pumped into the condenser
where it cools by giving off heat to air passing over the
condenser fins. As the refrigerant cools in the con-
denser, it condenses into a liquid. Still under high pres-
sure, the liquid refrigerant passes into the receiver. The
receiver acts as a reservoir to furnish refrigerant to the
expansion valve at all times. From the receiver, the high
pressure liquid refrigerant passes to the expansion
valve. The expansion valve meters refrigerant into the
evaporator where a low pressure is maintained by the
suction side of the compressor. As it enters the evapo-
rator, the refrigerant immediately begins to boil by ab-
sorbing heat from the air passing over the evaporator
core. Having given up its heat to boil the refrigerant, the
air is cooled and passes into the passenger compartment
of the vehicle. From the evaporator the vaporized refrig-
erant is drawn back to the compressor to repeat the
cycle.