Refrigerant Circuit O-Ring Seals - Audi Q7 2007 Repair Manual

Audi Q7 2007 ➤
Heating, Ventilation and Air Conditioning - Edition 04.2013
♦ To prevent the compressor from switching off when the max‐
imum permissible refrigerant temperature is briefly exceeded
(may occur under certain conditions of operation), the Clima‐
tronic Control Module - J255- front A/C control head switches
off compressor only if refrigerant temperature -A- rises above
the temperature characteristic curve marked with -D- in the
table a minimum of 30 seconds at the outside temperature
-B- currently measured and under the operating conditions
described below. Excessive refrigerant temperature is meas‐
ured in several consecutive measurement cycles, compressor
can no longer switch on (repair malfunction cause, check and
erase DTC memory).
♦ Since on this vehicle the refrigerant pressure is not evaluated
together with refrigerant temperature and depending on oper‐
ating conditions it is possible that temperature in refrigerant
circuit can also rise sharply for a brief period with a correctly
charged system (for example, running at full output at high
outside temperatures), refrigerant temperature is evaluated
only under certain operating conditions.
– Engine RPM less than 1,000/min.
– Compressor switched on for at least two minutes
– Passenger compartment temperature less than 40° C
– Vehicle speed was greater than 50 km/h at least one time be‐
fore each evaluation
– Vehicle speed is currently less than five km/h
– Evaluation by "adaptation" not switched off.
Note
A new measurement cycle begins the next time the 50 km/h
♦
limit is exceeded
If detected that the temperature characteristic curve -C- is ex‐
♦
ceeded in several measurement cycles, a DTC is entered in
DTC memory as a warning of a possible malfunction.
3.6

Refrigerant Circuit O-Ring Seals

♦ Always use only once. For replacing, refer to the Parts Cata‐
log.
♦ Lubricate with refrigerant oil before installing. Refer to the
Parts Catalog.
♦ Pay attention to correct positioning on pipe/in groove.
♦ Ensure cleanliness when working.
Note
♦ Install only O-ring seals that are resistant to refrigerant R134a
and corresponding refrigerant oil. These O-ring seals are col‐
or-coded to avoid mistakes (currently "red", "light purple" and
"dark purple"). Refer to the Parts Catalog.
The O-ring seal dimensions -a- and -b- are different depending
♦
on installed location: Refer to the Parts Catalog.
In addition to the color-coded O–ring seals, black O-ring seals
♦
are also installed during production for certain connections.
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Rep. Gr.87 - Air Conditioning
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