Audi A2 2001 - Page 172

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Possible Deviation From
Specification
Possible Cause Of Fault Corrective Action
• High and low pressure
normal at first
• After some time, high
pressure increases
above specification and
low pressure drops to
value in graph or below
• Required cooling output
is no longer attained.
♦ Expansion valve malfunctioning
♦ Moisture in refrigerant circuit
– Replace fluid reservoir (with dryer)
and evacuate refrigerant circuit for
at least 3 hours (see notes)
– Examine expansion valve for dirt
or corrosion; replace if necessary
– Clean refrigerant circuit (flush with
refrigerant R134a, refer to
⇒ “1.4.13 Refrigerant Circuit
Flushing With Refrigerant R134a“,
page 32 or blow through with com‐
pressed air and nitrogen, refer to
⇒ “1.4.12 Refrigerant Circuit
Flushing With Compressed Air
and Nitrogen “, page 29 ).
• High and low pressure
normal at first
• After lengthy operating
period, low pressure
drops excessively
(evaporator ices up)
Note
♦ It is not initially necessary to clean the refrigerant circuit (flush
using refrigerant R134a, refer to
⇒ “1.4.13 Refrigerant Circuit Flushing With Refrigerant
R134a“, page 32 or blow through using compressed air and
nitrogen, refer to
⇒ “1.4.12 Refrigerant Circuit Flushing With Compressed Air
and Nitrogen “, page 29 ) when this problem occurs since nor‐
mally, there is only a small quantity of moisture in the system
which can be removed by lengthy evacuation.
♦ If problem involving moisture in refrigerant circuit only occurs
after a lengthy operating period or only infrequently (low pres‐
sure drops below specification and evaporator ices up), it is
sufficient to replace the dryer (adjust quantity of refrigerant oil).
Refrigerant circuit is then to be evacuated for at least 3 hours.
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
168 Rep. Gr.00 - General, Technical Data