Discharging, Adding Oil, Evacuating; Systems - Pontiac Fiero 1988 Service Manual

1B-18 AIR CONDITIONING
HANDLING OF REFRIGERANT LINES AND
FITTINGS
Tighten all tubing connections as shown in
torque chart (Figure 16). INSUFFICIENT OR
EXCESSIVE TORQUE WHEN TIGHTENING CAN
RESULT IN LOOSE JOINTS OR DEFORMED
JOINT PARTS. Either condition can result in refrig-
erant leakage.
All metal tubing lines should be free of dents or
kinks to prevent loss of system capacity due to line
restriction.
• The flexible hose lines should never be bent to a
radius of less than four (4) times the diameter of
the hose.
• The flexible hose lines should never be allowed
to come within a distance of 63.5mm (2-1/2") of
the exhaust manifold.
• Flexible hose lines should be inspected regularly
for leaks or brittleness and replaced with new
lines if deterioration or leaking is found.
• When disconnecting any fitting in the refrigera-
tion system, the system must first be discharged
of all Refrigerant-12. Proceed very cautiously
regardless of gage readings. Open very slowly,
keeping face and hands away so that no injury
can occur if there happens to be liquid Refriger-
ant-12 in the line. If pressure is noticed when
fitting is loosened, allow it to bleed off as
described under DISCHARGING, ADDING
OIL, EVACUATING AND CHARGING PRO-
CEDURES FOR A/C SYSTEMS.
• In the event any refrigerant line is opened to the
atmosphere, it should be immediately capped or
taped to prevent entrance of moisture and dirt,
which can cause internal compressor wear or
plugged lines, in the condenser and evaporator
core and expansion (orifice) tubes or compressor
inlet screens.
• The use of the proper wrenches when making
connections on O-ring fittings is important. The
opposing fitting should always be backed up
with a wrench to prevent distortion of connecting
lines or components. When connecting the flexi-
ble hose connections, it is important that the
swaged fitting and the flare nut, as well as the
coupling to which it is attached, be held at the
same time using three (3) different wrenches to
prevent turning the fitting and damaging the
ground seat.
• O-rings and seats must be in perfect condition. A
burr or piece of dirt may cause a refrigerant leak.
When replacing the O-ring, first dip it in clean
525 viscosity refrigeration oil.
MAINTAINING CHEMICAL STABILITY IN
THE REFRIGERATION S Y S T E M
The efficient operation and life of the air condi-
tioning system is dependent upon the chemical stabil-
ity of the refrigeration system. When foreign
materials, such as dirt, air, or moisture, contaminate
the refrigeration system, they will change the stability
of the Refrigerant-12 and 525 viscosity compressor
oil. They will also effect pressure-temperature rela-
tionship, reduce efficient operation and possibly cause
interior corrosion and abnormal wear of moving parts.
The following general practices should be
observed to insure chemical stability in the system:
1. Before disconnecting a refrigerant connection,
wipe away any dirt or oil at and near the connec-
tion to reduce the possibility of dirt entering the
system. Both sides of the connection should be
capped, plugged or taped as soon as possible to
prevent the entry of dirt, foreign material and
moisture.
2. Keep tools clean and dry. This includes the
manifold gage set and replacement parts.
3. When adding 525 viscosity refrigerant oil (see
ADDING OIL in the DISCHARGING,
A D D I N G O I L , E V A C U A T I N G AND
CHARGING PROCEDURES FOR A/C SYS-
TEMS), the transfer device and container
should be clean and dry to assure that refrigera-
tion oil remains as moisture-free as possible.
4. When it is necessary to "open" an A/C system,
have everything needed ready and handy so that
as little time as possible will be required to per-
form the operation. Do not leave the A/C system
open any longer than is necessary.
5. Any time the A/C system has been "opened,"it
should be properly evacuated before recharging
with Refrigerant-12 according to the DIS-
CHARGING, ADDING OIL, EVACUATING
& CHARGING PROCEDURES FOR A/C
SYSTEMS.
All service parts are dehydrated and sealed
prior to shipping. They should remain sealed until just
prior to making connections. All parts should be at
room temperature before uncapping. (This prevents
condensation of moisture from the air entering the
system.) If, for any reason, caps are removed but the
connections are not made, parts should be resealed as
soon as possible.
DISCHARGING, ADDING OIL
f
EVACUAT-
ING AND CHARGING PROCEDURES FOR
A/C S Y S T E M S
The refrigerant system may be discharged,
evacuated and charged using air conditioning service
charging station J-23500-01 or equivalent, or the
manifold and gage set J-23575-01 and 420ml (14 oz.)
disposable cans of Refrigerant-12 (Figure 10).
Charging lines from the charging station or
manifold and gage set require the use of gage adapters
to connect to the system service fitting. A straight
gage adapter J-5420 and a 90° angle gage adapter J-
9459 are available (see A/C Special Tools).
Always wear goggles and wrap a clean cloth
around fittings and connections when doing work that