Audi A2 2001 - Page 166

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Possible Deviation From Specifica‐
tion
Possible Cause Of Fault Corrective Action
• High and low pressure normal at
first After some time,
• high pressure increases above
specification
• Low pressure quickly drops to
value in graph or below,
• Required cooling output is no lon‐
ger attained.
Moisture in refrigerant circuit – Check accumulator (with dryer)
and restrictor and replace if nec‐
essary, then evacuate refriger‐
ant circuit for at least 3 hours
(see note)
– Clean refrigerant circuit (flush
with refrigerant R134a, refer to
⇒ “1.4.13 Refrigerant Circuit
Flushing With Refrigerant
R134a“, page 32 or blow
through with compressed 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
♦ 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.
♦ 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.
Possible Deviation From Specifica‐
tion
Possible Cause Of Fault Corrective Action
• High pressure normal
• Low pressure too low (see graph)
• The required cooling perform‐
ance is obtained
A/C compressor faulty. – Clean refrigerant cir‐
cuit (flush with refrig‐
erant R134a, refer to
⇒ “1.4.13 Refrigerant
Circuit Flushing With
Refrigerant R134a“,
page 32 or blow
through with com‐
pressed air and nitro‐
gen, refer to
⇒ “1.4.12 Refrigerant
Circuit Flushing With
Compressed Air and
Nitrogen “, page 29 ).
– Replace A/C com‐
pressor.
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
162 Rep. Gr.00 - General, Technical Data