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18-16
1977 PONTIAC SERVICE MANUAL
WHEN DISCONNECTING ANY FITTING IN
THE REFRIGERATION SYSTEM, THE SYSTEM MUST
FIRST BE DISCHARGED OF ALL REFRIGERANT-12.
HOWEVER,
PROCEED
VERY
CAUTIOUSLY
REGARDLESS OF GAGE READINGS. OPEN VERY
SLOWLY, KEEPING FACE AND HANDS AWAY SO
THAT NO INJURY CAN OCCUR I F THERE HAPPENS
TO BE LIQUID REFRIGERANT-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 PROCEDURES FOR
C.C.O.T. 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, condenser and
evaporator core, expansion tubes (orifice) or compressor inlet
screens.
The use of the proper wrenches when making
connections on O-ring fittings is important. The use of
improper wrenches may damage the connection. The
opposing fitting should always be backed up with a wrench
to prevent distortion of connecting lines or components.
When connecting the flexible 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 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.
Always replace the O-ring when a connection has been
broken. When replacing the O-ring, first dip it in clean
refrigeration oil.
CAUTI 0 N:
Where
steel
to
aluminum
connections are king made, use torque for
aluminum tubing (see F i .
1 B - 2 2 ) .
MAINTAINING CHEMICAL STABILITY
IN THE REFRIGERATION SYSTEM
The efficient operation of the air conditioning
refrigeration system is dependent upon on the pressure-
temperature relationship of pure Refrigerant-12. As long as
the system contains pure R-12 (plus a certain amount of 525
viscosity compressor oil which mixes with the R-12, it is
considered to be chemically stable.
When foreign materials, such as dirt, air or moisture are
allowed to get into the system they will change the pressure-
temperature relationship of the Refrigerant-12. Thus, the
system will no longer operate at the proper pressures and
temperatures and the efficiency will decrease.
The following general practices should be observed to
insure chemical stability in the system:
1. Whenever it becomes necessary to disconnect a
refrigerant connection, wipe away any dirt or oil at and near
the connection to eliminate 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 entrance
of dirt, foreign material and moisture. (It must be
remembered that all air contains moisture. Air that enters any
part of the refrigerant system will carry moisture with it and
the exposed surfaces will collect the moisture quickly.)
2. Keep tools clean and dry. This includes the gage set
and replacement parts.
3. When adding 525 viscosity refrigerant oil (see
ADDING OIL in the "Discharging, Adding Oil, Evacuating
and Charging Procedures for C.C.O.T. A/C Systems"), the
container/transfer tube through which the, oil will flow
should be exceptionally clean and dry due to the fact that
refrigeration oil is as moisture-free as it is possible to make
it. Therefore, it will quickly absorb any moisture with which
it comes in contact. For this reason, the oil container should
not be opened until ready for use and then it should be capped
immediately after use.
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 perform 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 re-charging with
Refrigerant- 12 according to DISCHARGING, ADDING
OIL, EVACUATING
&
CHARGING PROCEDURES
FOR C.C.O.T. A/C SYSTEMS.
REFRIGERANT CHARGING
PRECAUTIONS
Normally, air conditioning systems are charged making
use of the J 23500-1 Charging Station which uses the 30 lb.
container of Refrigerant- 12. 14 oz. Refrigerant- 12 disposable
cans are also used. Discharging, Adding Oil, Evacuating and
Charging Procedures for C.C.O.T. Systems are described on
following pages in the Service Manual.
With 14 oz. Disposable Can Charging:
Do not Charge while compressor system is hot.
Empty container completely before disposing.
When opening valves designed for use with container,
follow manufacturer's directions carefully.
Always use pressure gages before and during Charging.
ALWAYS CHARGE THROUGH LOW-SIDE OF
A/C SYSTEM (low-side fitting is found on Accumulator).
NEVER connect on HIGH-SIDE of A/C system or
to any system having a pressure higher than indicated on the
R- 12 container.
See Disposable Can Charging procedures later in
section.
With J 23500-01 Charging Station:
Follow manufacturer's directions carefully with three
exceptions:
HI-PRESSURE VALVE OF GAGE SET SHOULD
BE CLOSED AT ALL TIMES DURING CHARGING
DO NOT CONNECT HIGH PRESSURE LINE TO
A/C SYSTEM
ALL EVACUATING AND CHARGING OF A/C
SYSTEM MUST BE PERFORMED THROUGH LOW
PRESSURE VALVEKINE TO LOW-SIDE SERVICE
FITTING ON ACCUMULATOR.
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