Pontiac FIREBIRD 1972 Service Manual page 111

1A-52 1972 PONTIAC SERVICE MANUAL
If full charge cannot be obtained, close both valves on'
gauge set, disconnect thermal limiter and jumper ter-
minals B and C on limiter connector, start engine,
and set temperature control lever to full cold position
with system in A/C mode. Open low pressure valve
on gauge set slowly and leave open until full charge
is added.
WARNING: Observe high pressure gauge while
charging with compressor running. Shut off en-
gine if pressure exceeds 535 psi. A large fan
placed in front of the car will help reduce exces-
sively high head pressure.
1
6. Close both valves on gauge set (high pressure valve
will already be closed if charging was completed by
running compressor) and close valve on refrigerant
drum.
If the engine was used to complete the charge into the
system, close valve on refrigerant drum to permit
compressor to draw any refrigerant left in the line
from the drum to the center fitting of the gauge set,
then close the low pressure valve on the gauge set.
Operate engine at 2000 rpm with temperature control
lever at full cold, blower speed switch on high and
system in the A/C position. After a few minutes of
operation, observe appearance of refrigerant in re-
ceiver-dehydrator liquid indicator (sight glass). If
bubbles are observed, open low pressure gauge valve
and valve on refrigerant drum to allow more refriger-
ant to enter system. Close valve when sight glass
clears.
(NOTE: If air inlet temperature is below 70°F. when
this check is made, bubbles may appear even though
the proper amount of refrigerant is in the system. Air
inlet temperature must be 70°F. or above to make an
accurate check.)
8.
When refrigerant has been installed, continue to op-
erate system and test for proper system pressures as
outlined under OPERATIONAL TEST.
9. When satisfied that the air conditioning system is
operating properly, stop engine, remove gauge set
and replace protective caps on P.O.A. valve and com-
pressor fittings.
WARNING: A considerable amount of refriger-
ant will collect in the high pressure line, since
some of this refrigerant will have condensed into
liquid refrigerant. Wrap the high pressure gauge
fitting at the compressor with a shop cloth
before disconnecting the valve from the gauge
fitting, to prevent injury to personnel.)
10. Using leak detector, check complete system for leaks,
as explained under LEAK DETECTORS.
11. Remove jumper from thermal limiter connector ter-
minals, check superheat switch terminal to ground
for open switch (no continuity) and connect limiter.
DISPOSABLE C A N METHOD
After having depressurized, repaired (if necessary) and
evacuated the refrigerant system, the system may be
charged as follows using refrigerant in disposable cans:
I. Obtain five 15 oz. cans or one 12 lb. can of refriger-
ant.
2. If using
1 5
oz. cans, mount four cans in J 6272-02
(multi-opener) or attach J 627 1 (single-can opener-
valve) on one can. If using the 12 lb. disposable can,
attach J 23390 (disposable can control valve) on can.
WARNING: Make sure outlet valve on opener is
closed (clockwise) before installing opener.
a. If the J 6272-02 multi-opener is used, raise lock-
ing lever, position four cans of refrigerant and
force locking lever down to secure cans and at
same time puncture top of can to make it ready
for charging.
b. If the J 6271 valve is used, back off the valve from
the can top retainer, slip the valve onto the can
and turn the valve into retainer until tight. DO
NOT open outlet valve during this operation as
turning the valve into the retainer punctures top
of can to make it ready for charging.
3. Connect center flexible line of gauge set to fitting on
a can opener valve. NOTE: If line at center gauge
fitting has not been purged of air, loosen line at center
fitting on gauge set and "crack" valve at can opener
(for a second or two) to force air from the line. Re-
tighten line at center fitting.
4. Open valve at refrigerant source and at low and high
pressure valves on manifold gauge set. Leave valve
open at refrigerant source until all refrigerant (when
using 15 oz. can) has entered the refrigeration system
or system is fully charged. Close valve on can.
a. If the system is charged using 15 oz. cans and the
J 6271 valve, disconnect valve from can. Leave
valve closed to flexible line to the center fitting of
the manifold gauge set. Install valve on a new and
full disposable can of refrigerant and repeat until
a sufficient number of 15 oz. cans of refrigerant
have been used to charge system to level specified
on compressor.
b. If system is charged using J 6272-02, close the
valve of opener after all cans are empty. Release
the locking lever and discard the four empty cans.
If this tool will be used to complete the charge
with additional cans to provide the required re-
frigerant charge, leave three of the empty cans in
position, locate one full can and lock the lever
into place. (These empty cans balance the assem-
bly and prevent the loss of refrigerant through the
open "series" passage.)