Audi Q5: Refrigerant Circuit, Discharging with Service Station
- Work procedure may vary depending on the type of tools
selected (the tool-specific operating instructions should
therefore be followed).
- The refrigerant circuit is to be discharged if parts of the
refrigerant circuit are to be removed, if there is any doubt
about the quantity of refrigerant in the circuit or if safety
precautions so require.
- All the necessary usage information for working with the
refrigerant service station can be found in the service station
operating instructions.
Draining:
- Turn off the ignition.
- Connect service station in line with operating instructions
to vehicle service connections. Refer to vehicle-specific
refrigerant circuit. Start up service station. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit or (vehicle-specific
repair manual).
Additionally on vehicles with an electric operated valves in
the refrigerant circuit, which cannot be opened without power
(for example the Audi Q7 e-tron):
Note
On vehicles with high-voltage system and additional
functions of the A/C system ("heat pump operation" or "cooling
the high-voltage battery") valves may be installed in the
refrigerant circuit which cannot be opened without power. These
valves are opened and closed for example via a step motor and
after switching off the ignition are no longer activated. To
completely drain, correctly discharge and charge the refrigerant
circuit no areas may be closed, for this reason the valves must
be opened before these procedures. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit and the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- Open the electrically activated valves, which to now open
without power using the Vehicle Diagnostic Tester in the "Guided
Fault Finding" function.
All
- Discharge the refrigerant circuit using the A/C service
station according to the operating instructions.
Caution
There is a risk of damaging the A/C compressor if
the refrigerant circuit is empty.
Do not start the motor if the refrigerant circuit is
empty.
- Depending on the version of the A/C Service Station,
the pressure of the refrigerant circuit may be less than
1 bar (14.5 psi) absolute pressure after it has been
discharged.
- Depending on the version of the A/C compressor, it
may be damaged if the pressure in the refrigerant
circuit is too low.
- Do not start the engine while the refrigerant
circuit pressure is less than the ambient pressure.
WARNING
There is a danger of ice-up.
Refrigerant may leak out if refrigerant circuit is
not discharged.
Refrigerant must be extracted before opening
refrigerant circuit. If refrigerant circuit is not
opened within 10 minutes of extraction, pressure may
form in refrigerant circuit due to evaporation. Extract
the refrigerant once more.
Note
- There is a possibility of refrigerant oil being extracted
from the refrigerant circuit together with the refrigerant. To
ensure compressor lubrication, the refrigerant oil in the
circuit must be topped up with fresh oil. Refer to
→ Chapter "Refrigerant R134a Capacities, Refrigerant Oil and
Approved Refrigerant Oils".
- On vehicles fitted with a compressor with no A/C clutch
(with A/C Compressor Regulator Valve -N280-) the engine should
not be run for longer than absolutely necessary with the
refrigerant circuit empty (A/C compressor always in operation as
well).
- On vehicles with a compressor with no A/C clutch, the engine
is only to be started following complete assembly of the
refrigerant circuit (avoid high engine speeds).
- Depending on the A/C compressor version, there may be a
valve installed on the high pressure side of the A/C compressor,
which prevents the liquid refrigerant from flowing back into the
compressor once the A/C is turned off. If an A/C compressor with
this valve is installed in a vehicle with a refrigerant circuit
having an expansion valve, then it may take some time until the
pressure in the high pressure side decreases (the expansion is
cold and the pressure in the low pressure side quickly increases
after it is turned off, the expansion valve closes and the
refrigerant flows slowly into the low pressure side). If the A/C
compressor is switched on (or the refrigerant circuit is
evacuated on the low pressure side) the pressure on the low
pressure side goes down, the expansion valve open and the
refrigerant can flow of the low pressure side.
- Depending on the version of the A/C service station, the
previous operating conditions and the ambient temperatures,
etc., the amount displayed by the A/C service station for the
evacuated refrigerant R134a can vary from the actual evacuated
amount. The amount displayed by the A/C service station for the
evacuated refrigerant is therefore only a reference point of the
amount of refrigerant actually evacuated from the refrigerant
circuit. Also pay attention to the A/C service station operating
instructions and technical product description.
Should work be performed on the vehicle after discharging
which does not require using the A/C service station
- Disconnect the A/C service station from the refrigerant
circuit and turn it off.
Should the refrigerant circuit after the discharge be
evacuated and refilled. Refer to
→ Chapter "Refrigerant Circuit, Charging with Service Station".
Refrigerant Circuit, Discharging with Service Station
- The work procedure is always to be performed as described in
the operating instructions for the A/C service station.
- The quantity of refrigerant oil in the circuit is checked
and if necessary corrected. Refer to
→ Chapter "Refrigerant R134a Capacities, Refrigerant Oil and
Approved Refrigerant Oils".
- The quantity of refrigerant in the service station is
checked.
The refrigerant circuit must be evacuated before it is
filled with refrigerant (vacuum). Moisture is also extracted
from the circuit.
Leaks may be found when evacuating the refrigerant circuit.
Evacuating:
Caution
- Do not start the engine during the evacuation
process or when there is a vacuum in the refrigerant
circuit.
- The A/C compressor could be damaged if the engine is
started when there is a vacuum in the refrigerant
circuit.
- Only start the engine when the refrigerant circuit
is filled.
- Turn off the ignition.
- Connect the service station to the power supply.
- Connect charging hose of service station to vehicles
refrigerant circuit with quick-release coupling adapter. Refer
to vehicle-specific refrigerant circuit. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
- Only tighten the handwheel on the quick-release coupling
adapter just enough so the valves in the service connections are
securely open. Do not put too much pressure on the valve.
Note
If pressure is to be measured after charging system on
vehicles with a service connection on one side of the
refrigerant circuit only, use valve adapter and charging hose
with valve opener. Refer to
→ Chapter "A/C Service Station, Connecting".
Additionally on vehicles with an electric operated valves in
the refrigerant circuit, which cannot be opened without power
(for example the Audi Q7 e-tron):
Note
- On vehicles with high-voltage system and additional
functions of the A/C system ("heat pump operation" or "cooling
the high-voltage battery") valves may be installed in the
refrigerant circuit which cannot be opened without power. These
valves are opened and closed for example via a step motor and
after switching off the ignition are no longer activated. To
completely drain, correctly discharge and charge the refrigerant
circuit no areas may be closed, for this reason the valves must
be opened before these procedures. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit and use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- The check valves in the refrigerant circuit in the flow
direction have a specified residual pressure (approximately 0.1
bar or 100 mbar). So that the refrigerant circuit can be
completely evacuates (residual pressure less than 5 mbar) all
electrically activated valves must be opened.
- Open the electrically activated valves, which to now open
without power using the Vehicle Diagnostic Tester in the "Guided
Fault Finding" function.
All
- Turn on the service station and evacuate the refrigerant
circuit for at least 30 minutes. The pressure reading must
indicate an absolute pressure of less than 10 bar (145 psi)
(corresponding to 990 mbar (14.36 psi) vacuum).
Note
At this pressure, both green Light Emitting Diodes (LED)
light up, for example, on the current service station. Refer to
the Parts Catalog (Tools; Special Tools and Equipment: A/C and
Heating).
- Turn off the service station and allow it to stand for at
least one hour.
- If the vacuum display (LED chain) does not change, the
system is free of leaks and can be charged.
Note
- A current vacuum reading (LED) is only obtained using the
current service station, for example (for currently available
service stations. Refer to the Parts Catalog (Tools; Special
Tools and Equipment: A/C and Heating) after pressing the
Evacuate button again.
- If with this service station the upper (green) LEDs do not
light immediately after turning on, either the refrigerant
circuit is leaking or there is still residual
moisture/refrigerant in the circuit.
If the vacuum is not maintained or cannot generate a
sufficient vacuum, perform the following:
- If the pressure in refrigerant circuit increases slowly
after evacuating, for example, through evaporation:
- If it is possible that the refrigerant circuit may have
leaks, evacuate and check the vacuum display again over several
hours Only when the vacuum is maintained can the refrigerant
circuit be charged.
- If the refrigerant circuit is sealed, it can be filled.
- If there is a leak that allowed enough air to enter during
evacuation that the A/C service station cannot generate a
sufficient vacuum or that the vacuum is lost immediately after
switching the A/C service station off:
- Determine the location of the leak in the refrigerant
circuit as follows:
Note
- A large leak can be identified if a maximum of pressure of
15 bar (217 psi) can be generated in the refrigerant circuit
using clean, dry compressed air or nitrogen. Refer to
→ Chapter "Refrigerant Circuit, Flushing with Compressed Air and
Nitrogen". If the leak is large enough, the sound of
escaping air or gas can be heard at the location of the leak.
- Add the compressed air or nitrogen to the closed refrigerant
circuit through the service connection after fitting it with a
quick-release connector adapter.
- The quick-release coupling adapter for service connections
can be connected to the air compressor using a modified filler
hose -A- (for example, with 5/8" 18
UNF threads, different from the threads on the quick-release
coupling adapter) and a suitable adapter
-B-. Refer to
→ Chapter "Improvised Tools". This keeps humidity,
oil and dirt coming out of the workshop compressed air system
from getting into the A/C refrigerant circuit. Also use a
combination fine-gauge filter for compressed air systems such as
those that are standard in paint shops. Install it between the
compressed air system and the filler hose
-A-. Refer to the Parts Catalog (Tools; Special Tools and
Equipment: A/C and Heating)
- A compressed gas cylinder filled with nitrogen
-3- can be connected to the closed
refrigerant circuit using a pressure gauge battery with a
pressure reducer for nitrogen (maximum reduction pressure: 15
bar (217 psi) ) -1- and a filler
hose -2- (for example, with 5/8" 18
UNF threads) connected to the service connection. A
quick-release coupling adapter must also be connected to the
service connection. Refer to
→ Chapter "Commercially Available Tools and Materials".
- Slowly increase the pressure in the refrigerant circuit to a
maximum of 15 bar (217 psi).
WARNING
- Nitrogen can leak uncontrolled from the cylinder.
- Make exclusive use of pressure reducers for nitrogen
cylinders (maximum work pressure 15 bar (217 psi) ).
- When testing for leaks with nitrogen (maximum
permissible pressure 15 bar (217 psi) ), always work with
a pressure reducer for nitrogen bottles.
- Use appropriate extraction units to draw off gas
mixture escaping from components.
- Find the location of the leak by listening for the sound of
venting gas.
- Repair the leak.
- Evacuate and again observe the vacuum display over a period
of hours. Only when the vacuum is maintained can the refrigerant
circuit be charged.
- If there is a leak that is small enough that no air or very
little air vents through it and the A/C service station can
generate a sufficient vacuum: The vacuum indicator does not
increase after switching the A/C system service station or only
increases slowly, indicating that air is only entering through a
small leak.
- Add 100 grams of refrigerant to the circuit, find the
location of the leak using an electronic leak detector and
repair it. Refer to
→ Chapter "Refrigerant Circuit, Tracing Leaks Using Electronic
Leak Detector") or add UV contrast dye to the
refrigerant and find the location of the leak with the Leak
Detection Kit -VAS6201A-and repair it. Refer to
→ Chapter "Leak Detection on Refrigerant Circuit Using Leak
Detection Kit -VAS6201A-".
- Empty the refrigerant circuit, if necessary. Refer to
→ Chapter "Refrigerant Circuit, Discharging with Service
Station".
- Evacuate and check the vacuum display again over several
hours. Only when the vacuum is maintained can the refrigerant
circuit be charged.
READ NEXT:
Note
The entire refrigerant charge can be added to either the
high or low pressure side. Refer to
→ Chapter "Refrigerant R134a Capacities, Refrigerant Oil and
Approved Refrigerant Oi
Note
If the mechanically driven Air Conditioning (A/C) compressor
was removed, rotate it approximately 10 times by hand before
using it for the first time (during or after installing, for
Possible Refrigerant Circuit Concerns
Test Requirements
Electrical Equipment, vacuum system and air duct
fault-finding has not revealed any faults. Refer to Guided Fault
Finding for the A/C system
SEE MORE:
Key set
Fig. 25 Key set
Master key with remote control and integrated mechanical key
You can centrally lock and unlock your vehicle and start the engine with the
master key with remote control. A mechanical key is integrated in the master
key.
Emergency key
The emergency key is not intended
Applies to vehicles: with Convenience key
The doors and the rear lid can be unlocked and
locked without operating the master key.
Fig. 30 Door handle: locking the vehicle
Unlocking vehicle
Take hold of the door handle. The door is unlocked
automatically.
Pull the handle to open the door.
Locki