Case 580SR, Service Manual

Page: 782 / 1068

22 SECTION 50 - CAB HEATING AND AIR CONDITIONING
CONDENSER
The condenser (1), located at the front of the ma-
chine in front of the engine radiator consists of a
number of turns of continuous coil mounted in a se-
ries of thin cooling fins to provide a maximum of heat
transfer in a minimum amount of space.
NOTE: the condenser after removal of the attaching
bolts can be slid out for cleaning.
The condenser receives the hot, high pressure re-
frigerant vapour from the compressor. The hot va-
pour passes through the condenser coils and
outside air is drawn through the condenser by the
engine cooling fan.
Heat moves from the hot refrigerant vapour into the
cooler outside air flowing across the condenser coils
and fins.
When the refrigerant vapour reaches the pressure
and temperature that will induce a change of state, a
large quantity of heat is transferred to the outside air
and the refrigerant changes to a high pressure warm
liquid.
The warm liquid refrigerant continues onto the re-
ceiver/drier where it is filtered and desiccated, to re-
move any moisture, before passing through an
outlet line to the thermostatic expansion valve.
RECEIVER DRYER
The receiver/dryer (2) situated behind the battery
stores the liquid refrigerant to be sure a steady flow
to the thermostatic expansion valve is maintained
under widely different operating conditions.
The drier section contains a desiccant (Molecular
sieve) to absorb any moisture within the system and
a filter prevents the entry of foreign particles.
NOTE: any moisture in the air conditioning system is
extremely harmful. Moisture not absorbed by the de-
hydrator will circulate with the refrigerant and drop-
lets may collect and freeze in the thermostatic
expansion valve orifice. This action will block the re-
frigerant flow and stop the cooling action. Moisture
will also react with refrigerant HFC 134a and the lu-
bricant to form a corrosive acid.
The desiccant can only absorb a limited amount of
moisture before reaching saturation point. Because
of this, after any system component replacement or
repairs requiring entry into the system, the receiver/
dryer should be replaced.
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