Chevrolet 1980 Light Duty Truck Service Manual page 74

1 B-28 AIR C O N D ITIO N IN G
Overhead System
5 lbs.-4 oz.
C-K
Models
5 lbs.
G
Models
C hart 1 B -1 0-R 12 C harging C apacities
New service A-6 Compressors are shipped with 10
ounces of oil already inside. Therefore, when a new A-6
Compressor is installed, its oil must first be drained and
measured to leave only that like amount drained and
measured in the oil compressor.
3. ON AN R-4 COMPRESSOR SYSTEM WITH
SIGNS OF ABUNDANT OIL LEAKAGE:
• ONLY THE ACCUMULATOR SHOULD BE
REMOVED from the system, oil drained and then
measured to determine correct quantity of oil replacement.
If the amount drained is 2 oz. or more, replace with like
amount. If less than 2 oz., replace with 2 oz. of new oil.
• IN ADDITION to this amount, add 1 oz. to replace
the amount captured in the old desiccant of the replaced
accumulator assembly. Because the R-4 Compressor has no
oil sump, it is not necessary to remove this compressor to
measure oil.
DISCHARGING EVA CUATING A D D IN G OIL
AND CHARGING PROCEDURES FOR C.C.O.T.
A /C SYSTEMS
The refrigerant system may be Discharged, Evacuated
and Charged using J-23500-01 air conditioning service
Charging Station or the J-5725-04 Manifold and Gage Set
and 14 oz. disposable cans of Refrigerant-12.
Charging lines from the Charging Station or Manifold
and Gage Set require the use of gage adapters to connect
to system service fittings. A straight gage Adapter J-5420
and a 90-degree angle gage Adapter J-9459 are available.
CAUTIO N: Alw ays w ear goggles and
w rap a clean cloth around fittings and
connections when
involves opening the refrigerant system.
If liquid refrigerant comes into contact
w ith the skin of eyes injury can result.
DISCHARGING THE C.C.O.T. A /C SYSTEM
In replacing any of the air conditioning refrigeration
components the system must be completely discharged of
Refrigerant-12.
ALWAYS DISCHARGE SYSTEM AT LOW SIDE
SERVICE FITTING.
1. With ignition turned OFF, remove protective cap
from low-side service fitting and connect Charging Station
J-23500-01 Gage Set as indicated in Figure IB-22.
Or, with ignition turned OFF and protective cap
removed from LOW-SIDE service fitting, discharge system
by SLOWLY connecting a gage hose to LOW-SIDE service
fitting on Accumulator and discharging into oil bottle (Fig.
Refrigerant Charge
C60
System
3 Lbs.-12 oz.
3 lbs.
doing w ork th a t
IB-23). As hose is slowly tightened down onto schrader
valve, Refrigerant-12 will be in to discharge from the system
into the container. If no discharge occurs, check for missing
or defective schrader depressor in hose fitting.
2. When the system is completely discharged (no
vapor escaping with hose fully-tightened down), measure,
record and discard any of the collected refrigerant oil. If this
quantity is 15 ml (1/2 oz.) OR MORE, it must be added
to system, plus any trapped in removed parts before
Evacuation and Charging with Refrigerant-12 (see C.C.O.T.
Refrigerant Oil Distribution
instructions on oil found in removed parts).
3. With the low-side of system fully discharged, check
high-side system fitting (on muffler) for remaining pressure
by connecting a downward directed 36" section J-5418-36B
charging line with attached J-25498 straight or J-25499 90°
angle fitting adapter SLOWLY tightened down to depress
the fitting valve.
4.
If pressure is found on the high-side
system, attempt to discharge high-side using same
procedure as used for low-side. (This condition indicates a
restriction and high-side components should be removed
and/or diagnosed to determine the area restricted.)
E VA CUATING , A D D IN G REFRIGERANT OIL
A N D CHARG ING THE C.C.O.T. A /C SYSTEM
If the system has been opened for any repair, or the
Refrigerant-12 charge lost, the system must be Evacuated
prior to Charging to remove any trace of air or moisture that
may have entered.
Evacuation and Charging is a combined procedure,
with all lines and gauges, as well as the system, to be purged
with R-12 and Evacuated just prior to Charging.
There are three standard Refrigerant-12 Evacuate and
Charge procedures which include Oil Addition:
• J-23500-01 Charging Station Method
• Disposable Can Method
• Drum Method
Under no circumstances should alcohol be used in the
system in an attempt to remove moisture, regardless of the
successful use of alcohol in other refrigerant systems.
Prior to Evacuation, check the low pressure gage for
proper calibration. With the gage disconnected from the
refrigeration system, be sure that the pointer indicates to the
center of "O". Lightly tap gage a few times to be sure pointer
is not sticking. If necessary, calibrate as follows:
a. Remove cover from gage.
b. Holding gage pointer adjusting screw firmly with one
hand, carefully force pointer in the proper direction in
proper amount to position pointer through the center of "O"
position. Tap gage a few times to be sure pointer is not
sticking. Replace gage cover.
J-23500-01 CHARG ING STATIO N M ETHO D
Follow Charging instructions provided with the J-
23500-01 Charging Station in use with the following
exceptions:
1. DO NOT CONNECT THE HIGH PRESSURE
LINE TO THE AIR CONDITIONG SYSTEM.
2. KEEP THE HIGH PRESSURE VALVE ON THE
CHARGING STATION CLOSED AT ALL TIMES.
for specific quantity
of the
LIG H T T R U CK S E R V IC E M AN U AL