1A-4
1968 PONTIAC SERVICE
MANUAL
check for
leaks
as outlined below, after a small
amount of Refrigerant-12 has
been
added
to the low
side
of the system*
a. Turn hand shut-off valves at the low and high
pressure
gauge
of the
gauge
set to
full
clockwise
position
with
the vacuum pump operating, then
stop
pump.
b.
Connect
flexible
line
from
center
fitting
of
the
gauge
set to refrigerant drum (drum should be
at room temperature).
NOTE:
It may be necessary to use reducer
J
5462-4 with washer J 5462-9 to attach flexible
hose to refrigerant drum.
c. Open shut-off valve on drum and loosen
flexible
line
fitting
at
center
fitting
at
gauge
set
so that refrigerant
will
purge all air
from
line.
Tighten
flexible
fitting
when certain all air has
been
purged
from
line.
d.
Open suction valve on
gauge
set. This
will
allow
refrigerant to
pass
from
the drum into the
system. When
pressure
stops
rising,
close
suc-
tion
valve on
gauge
set and valve at refrigerant
drum
(as refrigerant drum Is at room tempera-
ture, only a small refrigerant
charge
will
enter
the system),
e. Using leak detector J 6084, check all fittings
•
in the system,
compressor
shaft
seal
and on
gauge
set for evidence of
leakage.
When general
area
of
leak has
been
found
with
the
test
torch, a
liquid
leak detector may be helpful In locating the exact
point
of
leakage.
After
leak has
been
corrected,
evacuate
the system again.
6. Turn the hand shut-off valves at the low and
high
pressure
gauge
of the
gauge
set to the
full
clockwise
position
with
the vacuum pump operating,
then
stop
pump. Carefully check low
pressure
gauge
to see that vacuum remains
constant.
If vacuum
reduces,
it indicates a leak in the system or
gauge
connections. See NOTE In
step
5
above
for method
of
locating leak.
CHARGING THE SYSTEM
The system should be charged only after
being
evacuated
as outlined in
EVACUATING
THE
SYSTEM.
REFRIGERANT
DRUM
METHOD
1. Connect
center
flexible
line of
gauge
set to
refrigerant drum.
NOTE:
It may be necessary to use reducer
J
5462-4 with washer J 5462-3 and fitting J 5462-9
to attach flexible line to refrigerant drum.
2.
Place
*
refrigerant drum in a
pail
of water
which
has
been
heated
to a maximum of
125°F.
CAUTION:
Do not allow temperature of water to
exceed
125
°F.
High temperature
will
cause exces-
sive
pressure and possible softening of fusible
safety plugs in the refrigerant drum. It may not be
necessary
to use hot water if a large drum is used
(over
approximately 100
lbs.).
3.
Place
refrigerant drum (In
pail
of water) on
scales
(bathroom or commercial, preferably com-
mercial),
Fig. 1A-3.
CAUTION:
Do not turn refrigerant drum upside
down as this would allow
liquid
refrigerant to enter
compressor
which may cause damage.
4.
If line at
center
gauge
fitting
has not
been
purged of air, loosen line at
center
fitting
on
gauge
set and crack valve on refrigerant drum to blow air
from
line.
Retighten line at
center
fitting
and record
exact weight of refrigerant tank in water on the
scales.
5. Open valve on refrigerant drum and both valves
on
gauge
set to allow refrigerant to
flow
into system.
Continue charging
until
the
scales
show that 4 1/8
pounds
of refrigerant
have
been
transferred
from
refrigerant drum to system for Pontiac or Tempest.
THE
FREON CHARGE FOR THE FIREBIRD CUSTOM
AIR
CONDITIONING
SYSTEM IS 3-3/4 LBS.
NOTE:
If
full
charge cannot be attained, close
both valves on gauge set, start engine, and turn
temperature control knob to
full
cold
position with
NORMAL
or A/C button depressed. Open low
pressure
valve on gauge set slowly and leave open
until
full
charge is added.
CAUTION:
Observe high pressure gauge while
charging
with compressor running. Shut off engine
if
pressure exceeds 375 psi. A large fan placed in
front
of the car
will
help reduce excessively high
head
pressure.
6. Close both valves on
gauge
set (high
pressure
valve
will
already by closed if charging was com-
pleted by running compressor) and
close
valve on
refrigerant drum.
NOTE:
If the engine was used to complete the
Refrigerant-12
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.
7.
Operate
engine at 2000 rpm
with
temperature
control
knob at
full
cold position and blower control
for
high
speed
with
NORMAL
or A/C button de-
pressed.
After
ten minutes of operation
observe
appearance
of refrigerant in receiver-dehydrator.
If
bubbles are observed, open low
pressure
gauge
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