Adding Refrigerant 1A-7 - Pontiac Grand Prix Service Manual

CUSTOM AIR CONDITIONING 1A-7
4. Turn on vacuum pump and open vacuum control
valve (no. 3).
5. With system purged as above, run pump until 26-28
inches of vacuum is obtained. Continue to run pump
for 15 minutes after the system reaches 26-28 inches
vacuum.
NOTE: In all evacuating procedures, the specification of
26-28 inches of mercury vacuum is used. These figures
are only attainable at or near sea level. For each 1000
feet above sea level where this operation is being
peIfonned, the specifications should be lowered by I
inch. Example: at 5000
3.
elevation, only 21 to 23
inches vacuum can normally be obtained.
6. If 26-28 inches vacuum (corrected to sea level)
cannot be obtained, close vacuum control valve (No. 3)
and shut off vacuum pump. Open refrigerant control
valve (No. 4) and allow some refrigerant to enter
system. Locate and repair all leaks.
7. After evacuating for 15 minutes, add 1/2 pound of
refrigerant to system as described in step 6 above.
Purge this 1/2 pound and re-evacuate for 15 minutes.
This second evacuation is to be certain that as much
contamination is removed from the system as possible.
8. 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.
9. Close low pressure valve on charging station. Fully
open station refrigerant control valve (No. 4) and
allow all liquid refrigerant to enter system. When full
charge of refrigerant has entered system turn off
refrigerant control valve (No. 4) and close both hand
shut-off valves.
10. If full charge of refrigerant will not enter system,
close high pressure control and refrigerant control
valves. Start engine and run at slow idle with
compressor operating. Crack refrigerant control valve
(No. 4) 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.
11. System is now charged and should be performance
tested before removing gauges.
ADDING REFRIGERANT-12
The following procedure sliould 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, if excessive
add oil if necessary. See ADDING OIL.
NOTE: This procedure will only apply i f the air inlet
temperature is above 7BF. at the condenser.
1. Remove caps from P.O.A. valve and compressor
gauge fittings. Attach gauge set to gauge fittings,
making sure Schrader adapter J 5420 is between low
pressure gauge hose and suction gauge fitting, and J
6163 is between high pressure gauge hose and
discharge gauge fitting.
2. Start engine, turn air conditioning temperature
control knob to full cold position, blower control for
high speed A/C mode. Operate for ten minutes at
2000 rpm to stabilize system.
3. Observe the refrigerant through the glass a v e r of
receiver-dehydrator with the system operating, to see if
there are any bubbles evident.
a. If no bubbles are evident, then bleed system slowly
through the discharge valve until bubbles appear in
the receiver-dehydrator. Add one pound of refrigerant
as explained under CHARGING THE SYSTEM.
b. If bubbles are visible in the receiver-dehydrator with
the temperature control knod at the full cold position
and the blower at "HI" speed, it indicates partial or
complete plug in a line, or a shortage of refrigerant, or
both. Correct condition. Add refrigerant as explained
below until the slight glass clears, then add another
one pound of refrigerant.
4. 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
satisfied that all air has been removed from gauge
lines. -Close (clockwise) both hand shut-off valves of
gauge set.
5. Partially charge system.
REFRIGERANT-12 DRUM METHOD
a. Place pail containing hot water that does not have a
temperature exceeding 125OF. on scales, place refriger-
ant drum in pan containing water, note weight, and
only open low pressure valve on gauge set.
b. Start engine, move temperature control knob to full
cold position, and place blower control for high speed.
Operate engine for ten minutes at 2000 rpm to
stabilize system.
c. With compressor operating, slowly open valve on
refrigerant drum and allow refrigerant to flow into
system (through manifold guage set) until liquid
indicator clears up and immediately shut off valve at
gauge set or on refrigerant drum. Check weight of