GMC 1982 Light Duty Truck Service Manual page 71

IB-28 AIR CONDITIONING
Fig. 1 B-23-Discharging the CCOT A /C System Without
Charging Station J-23500-01
D istribution for specific quantity of oil normally
retained in removed parts).
5. If adding oil is necessary, remove the suction hose at
the accumulator outlet pipe connection and pour the
correct quantity of refrigerant oil into the hose or pipe
and then properly reconnect hose or pipe. (See
Discharging Step No. 4 and C.C.O.T. Refrigerant Oil
Distribution for specific quantity instructions).
CCOT REFRIGERANT OIL DISTRIBUTION
A-6 CO M PR ESSO R — requires 300 ml (10 oz.) of 525
viscosity refrigerant oil.
R-4 C O M PRESSO R — requires 6 oz. (180 ml) of 525
viscosity refrigerant oil.
New oil quantities must be added to the system during
Service component replacement and conditions stated as
follows:
A. W HEN TH ER E ARE NO SIG N S of excessive oil
leakage, for:
• Compressor - Remove, drain oil, measure, replace
same amount of new oil plus 1 oz. (30 ml). On A-6
compressor, if amount of oil drained is 240 ml (8 oz.)
or more, an oil overcharge should be suspected.
• Evaporator - Add 90 ml (3 oz.).
• Condenser - Add 30 ml (1 oz.).
• Accumulator - Remove, drain oil, measure, replace
same am ount of new oil plus 60 ml (2 oz.) to
com pensate for that retained by the original
accumulator dessicant.
B. W ITH SIG N S OF EX CESSIV E OIL LEAKAGE,
for:
A -6 Compressor Systems
Remove Compressor A N D A ccum ulator. Drain,
measure and record TOTAL oil from both components.
Discard old oil.
If less than 180 ml (6 oz.), add 180 ml (6 oz.) of new oil
to system.
If more than 180 ml (6 oz.), add same amount of new
oil as drained.
If a new Accumulator must be added to A-6 system,
add 2 additional ounces (60 ml) of oil to compensate for that
held/absorbed by the original accumulator dessicant.
R-4 Compressor Systems
A. With no signs of excessive oil leakage, add:
• Compressor - Remove, drain oil, measure, replace
same amount of new oil plus 30ml (1 fl. oz).
• Evaporator - Add 90ml (3 fl. oz).
• Condenser - Add 30 ml (1 fl. oz).
• Accumulator - Remove, drain oil, measure, replace
same amount of new oil plus 60ml (2 fl. oz) to
com pensate for that retained by the original
accumulator dessicant.
B. With signs of excessive oil leakage:
• Remove only the Accumulator. Drain, measure and
record quantity of oil in A ccum ulator. It is not
necessary to remove and drain the R-4 Compressor
because the Compressor only retains a minimum
quantity of oil.
• If less than 90ml (3 fl. oz), add 90ml (3 fl. oz) of new
oil to system.
• If more than 90ml (3 fl. oz), add same amount of new
oil as drained.
• If a new Accumulator must be added to R-4 system,
add 60ml (2 fl. oz) additional oil, to compensate for
that held/absorbed by the original A ccum ulator
dessicant.
EVACUATING AND CHARGING THE CCOT 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.
Evacuation and Charging is a combined procedure,
and all gage lines must be purged with R efrigerant-12 prior
to charging.
There are three standard R efrigerant-12 evacuate and
charge procedures:
• J-23500-01 Charging Station Method
• Disposable Can Method
• Drum Method
NOTICE: Under no circumstances should alcohol be
used in the system in an attem pt to remove moisture.
Damage to the system components could occur.
GAGE CALIBRATION
Prior to Evacuation, check the low pressure gage for
proper calibration and determ ine if vacuum system is
operating properly. 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
to position pointer at the "O " position. Tap gage a
few times to be sure pointer is not sticking. Replace
gage cover.
VACUUM SYSTEM CHECK
Before connecting vacuurrfpum p to the A /C system,
run pump connected to the low pressure gage to determine