1996 AUDI A4 Refrigerant System Components Workshop Manual

87-29

Evaporator


Liquid refrigerant entering the evaporator absorbs heat from air passing
through the evaporator fins and cools the air. As the refrigerant absorbs
heat it turns to vapor and then is suctioned by the compressor.
Note:
Illustration shows the evaporator from an Audi 90 model.
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87-30

A/C refrigerant low pressure switch -
F73-


Function

Switches A/C Clutch -N25- OFF if system suction pressure is too low (low
refrigerant charge). This switch protects the compressor if the refrigerant
system is empty.
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87-31

Accumulator


The accumulator traps the mixture of refrigerant vapor and gas coming
from the evaporator. While in the accumulator, the refrigerant vapor turns
to gas and, along with the refrigerant oil, is then suctioned by the
compressor.
An oil extraction passage is incorporated into the accumulator to ensure
that refrigerant oil flowing with the refrigerant does not remain in the
accumulator.
Any moisture in the system is absorbed by the desiccant in the
accumulator.
Note:
Do not remove caps -A- and -B- until ready to install new accumulator. If
caps are removed too soon, the dessicant becomes saturated with
moisture after a very short time. If this occurs, the accumulator must be
replaced.
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87-32

O-rings


O-rings seal the connections between components of the A/C system.
Use only O-rings which are compatible with R-134a refrigerant and
refrigerant (PAG) oil. Refer to the most recent parts information when
obtaining new O-rings.
Notes:
Handle O-rings only in a clean working environment.Do not reuse O-rings, always replace.Always use correct size O-rings (dimensions -a- and -b-).Lubricate O-rings with refrigerant (PAG) oil before installing.Always ensure O-rings are properly installed on pipe/component
mounting flanges/grooves. O-ring and torque specifications also apply to threaded connections in
the A/C lines.
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87-33

Hoses and lines

The mixture of refrigerant oil (PAG oil) and
refrigerant R-134a attacks some metals and
alloys (for example, copper) and breaks down
certain hose material. Use only hoses and lines
which are identified with the lettering "R-134a."
Hoses and lines are secured with threaded
connections. Always properly torque hose and
line connections.
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