Porsche P-80 2005, Manual

Page: 83 / 108

A/C Refrigerant System Service & Diagnosis
Climate Control Systems Diagnosis & Repair
Page 5.5
A/C Refrigerant System Service Procedures
The A/C service station recovers and stores the
refrigerant while the system is being repaired. The service
station must recycle the refrigerant so that it is pure for
reuse. Finally the service station must remove all residual
air and moisture from the system and then recharge it with
an accurately measured quantity of refrigerant.
The following information explains A/C service procedures.
The information generally applies to all types of service
stations. Be sure to consult the operating instructions for
the specific service equipment that you are using and
always follow the safety recommendations.
Recovery
To prepare for refrigerant recovery, be sure that the
engine and A/C system are OFF. Attach the service hoses
to the vehicle service ports. Open the service hose valves
on the quick connectors if present (not all service hoses
have them). Be sure that both high side and low side
gauge hand valves on the service station control panel are
closed.
Check both gauges on the control panel before continuing.
If the pressures are zero, the system is completely
discharged and may contain air. DO NOT ATTEMPT
RECOVERY as this will cause air to be drawn into the
refrigerant storage tank.
If the pressure gauges do not read zero, open both high
side and low side gauge hand valves on the service station
control panel. Open the storage tank valves as described
in the operating instructions.
Recover refrigerant per service station instructions. Most
service stations will weigh the recovered refrigerant and
indicate how much refrigerant was removed. Note this
value as it can help diagnosis later.
The recovery process creates a shallow vacuum of about
15 in.Hg. in the A/C system. Usually the machine will turn
off when this vacuum is reached. Wait five minutes and
watch the low side pressure gauge to see if pressure
rises. Often, pressure will rise because remaining
refrigerant trapped in refrigerant oil, desiccant, etc. is now
boiling off in the low pressure. If pressure rises above 0
in.Hg., again perform the recovery. Repeat until pressure
does not rise after five minutes.
Note:
Depending on the system you’re running, deep vacuum is
not created during recovery. If a deep vacuum were
achieved, any water in the system would boil at room
temperature and be pulled into the refrigerant storage
container, contaminating the refrigerant and overloading
the service station filter.
Any moisture in the system will be removed later during
evacuation, when a deep vacuum is reached. When the
recovery operation is complete, close both high side and
low side gauge hand valves on the service station control
panel. Also close the storage tank valves.
Oil Separator
While recovering, approx. 15-20 cc (0.5-0.7 oz.) of refrig-
erant oil may be removed from the system along with the
refrigerant. After recovering, measure the quantity of oil in
the oil separator. Follow the instructions for your machine.
This is the minimum amount of oil that must be replaced
with fresh oil when you recharge the system. If any
component in the refrigerant circuit is replaced, more oil
may have to be added, as the oil circulates throughout the
system and coats the inside of every component.
Notes: