Porsche P-80 2005, Руководство пользователя

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A/C Refrigerant System Service & Diagnosis
Climate Control Systems Diagnosis & Repair
Page 5.7
Recharging
A/C systems can be recharged by two methods:
• Pumping liquid refrigerant into the system high side with
A/C OFF.
• Allowing the A/C compressor to draw refrigerant gas
into the low side with A/C ON.
Most A/C service stations introduce liquid refrigerant on
the system high side. Since the A/C compressor can be
damaged by liquid refrigerant, you must be sure that the
low side gauge hand valve is closed and the high side
hand valve is open when recharging. This will allow refrig-
erant into the system high side only. The refrigerant will be
distributed throughout the system once the system is
started.
The quantity of refrigerant to recharge is determined by
weight. The specification is on a label in the engine
compartment and also in the Workshop Manual
Information.
Be sure that the storage tank has sufficient refrigerant to
charge the system. Modern A/C systems do not contain
much refrigerant. so it is important to recharge the correct
amount. To do this, the service station tank scale must be
accurate. When recharging, be sure that the tank hoses
are not stretched and do not bump, move or touch the
machine or the storage tank.
After the system is charged, turn the A/C ON with the
engine idling. Be sure to close the service station high
side gauge hand valve before turning the A/C
system ON. If this valve is left open, the refrigerant
storage tank will be exposed to high side pressures and
can explode.
The A/C system should be ON continuously for at least
two minutes with the engine idling to properly distribute
the refrigerant oil.
Performance test the system as described in this section.
When system performance has been verified, remove the
service hoses. Recover the refrigerant in the hoses per
the instructions and close the valves on the storage tank
and control panel.
A/C System Performance Testing
An A/C system performance test should be performed
before any service to verify a customer complaint of poor
cooling performance. It should also be performed to verify
that repairs have corrected the problem.
Always be sure that the A/C system is mechanically OK
before suspecting the electronics or controls. A general
procedure for performance testing the A/C system
includes the following steps. Always consult the Repair
Information for model-specific procedures and
specifications.
• Close doors, windows, and sliding roof.
• Insert temperature probe into center vent
• Measure ambient temperature
• Open all dash vents
• Switch ignition on
• Press recirculating air button
• Set temperature control to maximum cooling
• Switch fresh air blower to stage four
• Start engine
• Operate air conditioner while idling
• Set engine speed to 2000 RPM (start of time measure-
ment)
Compare the outlet air temperature with specifications. If
the specified temperature is not obtained, follow
diagnostic procedures in the service manual to determine
the cause.