Adding Refrigerant - Pontiac FIREBIRD 1972 Service Manual

1A-54 1972 PONTIAC SERVICE MANUAL
f. Disconnect oil injector tool and re-cap all open-
ings.
Turn off vacuum pump valves with pump operating,
then shut off pump. Check low pressure gauge for
approximately 2 minutes to make sure vacuum re-
mains constant (no leak).
Only after evacuating as above, system is ready for
charging. Note reading on sight glass of charging
cylinder. If it does not contain a sufficient amount for
a full charge, fill to proper level.
Close low pressure valve on charging station. Fully
open station refrigerant control valve and allow all
liquid refrigerant to enter system. When full charge
of refrigerant has entered system turn off refrigerant
control valve and close both hand shut-off valves.
If full charge of refrigerant will not enter system,
close high pressure control and refrigerant control
valves. Disconnect thermal limiter and jumper termi-
nals B and C of limiter connector. Start engine and
run at low idle with compressor operating. Crack
refrigerant control valve and low pressure control on
station. Watch low side gauge and keep gauge below
50 psi by regulating refrigerant control valve. Closing
valve will lower pressure. This is to prevent liquid
refrigerant from reaching the compressor while the
compressor is operating. When required charge has
entered system, close refrigerant control valve and
close low pressure control.
System is now charged and should be performance
tested before removing gauges.
Remove jumper and connect thermal limiter.
FILLING CHARGING CYLINDER
1. Open control valve on refrigerant container.
2. Open valve on bottom of charging cylinder allowing
refrigerant to enter cylinder.
3. Bleed charging cylinder to valve (behind control
panel) only as required to allow refrigerant to enter
cylinder. When refrigerant reaches desired charge
level, close valve at bottom of charging cylinder and
be certain cylinder bleed valve is closed securely.
(NOTE: While filling the cylinder, it will be neces-
sary to close the bleed valve periodically to allow
boiling to subside so that refrigerant level in the
charging cylinder can be accurately read.)
ADDING REFRIGERANT
The following procedure should be used in adding small
amounts of refrigerant that may have been lost by leaks
or while opening system for servicing the compressor.
Before adding refrigerant to replace that lost by leaks,
check for evidence of oil loss, and add oil if necessary. See
ADDING OIL.
This procedure will only apply if the air inlet temperature
is above 70°F. at the condenser.
Disconnect thermal limiter and place jumper wire
between terminals B and C of limiter connector.
Remove caps from P.O.A. valve and compressor
gauge fittings. Attach gauge set to gauge fittings,
making sure adapter J 5420 is between low pressure
gauge hose and suction gauge fitting, and J 9459 is
between high pressure gauge hose and discharge
gauge fitting.
Start engine, turn air conditioning temperature con-
trol lever to full cold position, blower switch to high
speed and system selector lever to the A/C mode.
Operate for ten minutes at 2000 rpm to stabilize sys-
tem.
Observe the refrigerant through the sight glass cover
of receiver-dehydrator with the system operating, to
see if there are any bubbles evident.
If no bubbles are evident, then bleed system
slowly through the discharge valve until bubbles
appear in the receiver-dehydrator. Add one-half
pound of refrigerant as explained under
CHARGING THE SYSTEM.
If bubbles are visible in the receiver-dehydrator
with the temperature control lever in the full cold
position and the blower at HI speed, it indicates
a partial or complete plug in a line, a shortage of
refrigerant, or both. Correct condition. Add re-
frigerant until the slight glass clears, then add
another one-half pound of refrigerant.
Attach flexible hose from center fitting of gauge set
loosely to refrigerant drum or on disposable can
valves. Open high and low pressure valves on the
gauge set slightly to purge pressure gauge lines of air.
Tighten fitting of refrigerant drum or can when satis-
fied that all air has been removed from gauge lines.
Close (clockwise) both hand shut-off valves of gauge
set.
Partially charge system.
REFRIGERANT DRUM METHOD:
Place pail containing hot water that does not have
a temperature exceeding 125°F. on scales, place
refrigerant drum in pan containing water, note
weight and only open low pressure valve on gauge
set.
Start engine, move temperature control lever to
full cold position and place blower switch on high
speed. Operate engine for ten minutes at 2000
rpm to stabilize system.