1993 DODGE TRUCK Service Repair Manual

24-12
HEATING
AND AIR
CONDITIONING

PERFORMANCE TEMPERATURE CHART

Garage
Ambient
Temperature
21
°C

(70°F) 26.5°C
(80°F) 32°C
(90°F) 3/.5°'J
(100T) 43°C
(110°F)

Discharge
Air Temperature
3-10°C
(38-50°F) 6-12°C
(42-54'F) 8-14°C
(46-58°F) 10-17°C
(50-62°F) 12-19°C
(54-66°F)

Compressor
Discharge Pressure
1344 a
1620 a
1861 kPag 2103 a 1379kPcg
2344 a

Compressor
Discharge Pressure

120 •
195 PS'9 160 .
235 PS'9 200 .
270 PS'9 240 .
305 PS'9 280 .
340 PS'9

Evaporator
Suction Pressure
124 kPag
207 a 138 kPag
241 J 269 kPag III kP°9
296 179 ,D
324 kPag

Evaporator
Suction Pressure

18 .
30 PS'9 20 .
35 pS'g 22
39 pS,g
25 .
43 pS'g 26 .
47 pS'9
J9124-97 pressure must drop to below -50 kPag (15 inch of vacu­

um).
If the condition is not met the H-valve is stuck
open and should be replaced. Remove Liquid C02 and
watch evaporator suction pressure; it should increase to a minimum of 262 kPag (38 psig) and then stabilize to a
pressure of 172-240 kPag (25-35 psig). Any H-valve
which does not produce this response is stuck open and should be replaced.
(4) Connect A/C water valve vacuum hose (gray)
and set temperature control in cool position.
(5) Set engine speed at 1,000 RPM and blower on

HI.
The evaporator suction pressure should be in the
range of 138-207 kPag (20-30 psig). If compressor dis­ charge is higher than 1 656 kPag (240 psig), check
for restricted discharge line, radiator overheating, air in system or faulty viscous fan drive. If discharge
pressure is less than 966 kPag (140 psig), check com­
pressor head gaskets and discharge reeds.
(6) Connect the electrical wires to the electronic
temperature cycling clutch switch.
VACUUM CONTROL SYSTEM ADJUSTMENTS
AND TESTS To keep the vacuum harness in place, common vi­
nyl tape (sometimes called plastic tape of electri­
cian's tape) cannot be used. It will cause the tube to
deteriorate directly under the tape, when high under­
hood temperatures are involved. A compatible nylon type of tape such as MS CH69 (#281) or an equiva­lent must be used.
The test of the push button switch operation deter­
mines whether or not the vacuum and electrical cir­ cuits are properly connected and the controls are
functioning properly. However, it is possible that this system operating perfectly at engine idle during high
manifold vacuum, may not function properly at high engine speeds. Before starting this test, stop engine and make certain the vacuum source hose at engine
intake manifold is tight on its connector.
EXPANSION (H) VALVE TEST
Test must be made at ambient temperature of
21°C-29°C (70°F-85°F).
After performing all previously mentioned tests,
conduct the H-valve test as follows:
(1) Operate the engine at 1,000 RPM with the win­
dows closed. Set air conditioning controls for MAX
A/C,
high blower, temperature control lever in full
reheat position and cycling clutch switch electrically
bypassed. Disconnect and plug the water valve vac­ uum hose in the engine compartment. (2) Operate the system for at least 5 minutes in or­
der to obtain partial stabilization and sufficient re­
heat to load the system. Pressure at the discharge service port should reach 966-1 656 kPag (140-240
psig) (Fig. 6). If head pressure of 966-1 656 kPag (140-240 psig) cannot be obtained, check system
charge level.

Fig.
6
Expansion
(H)
Valve
Test

WARNING:
EXTREME
CARE
MUST
BE
USED
WHEN
HANDLING
LIQUID
C02 AS
SKIN
INJURY
CAN OC­

CUR
IF
PROTECTIVE
GLOVES
ARE NOT
WORN.
(3) Put Liquid C02 on control head (completely cover
head) for a minimum of 30 seconds. Evaporator suction

•

HEATING
AND AIR
CONDITIONING
24 - 13 Start Vacuum Pump Tool
C-4289
and connect the
Vacuum Test Set Tool
C-3707.
With the prod
blocked, adjust bleed valve to obtain a vacuum read­ ing of exactly -27 kPag (8 inches of mercury) - (Fig.
7).

VACUUM PUMP

Fig.
7
Adjust
Vacuum
Test
Bleed
Valve

It is essential that the bleed valve be adjusted so
the vacuum gauge pointer will return to exactly -27 kPag (8 inches) with the prod blocked. Otherwise a
false reading will be obtained when the control cir­
cuit is tested.
Alternately release and block the hose prod several

times.
Make sure the bleed valve is adjusted so the vacuum gauge pointer returns to exactly -27 kPag (8 inches of vacuum) when the prod blocked (Fig. 7).
Disconnect engine vacuum source hose at engine
intake manifold and insert vacuum tester hose prod
into source hose leading to push button switch. Place
vacuum gauge on the cowl so it can be observed from
the driver's position as push buttons are operated.
Start the test by depressing the control HEAT
mode button. Vacuum tester gauge needle will drop
until the actuator has operated. It should then return
to -25 to -27 kPag
(7-1/4
to 8 inches) depending on
vacuum leakage. Continue to depress; OFF, MAX.

A/C,
A/C,
VENT,
DEFROST
and
HEAT
mode but­

tons.
Allowing time for actuators to operate after each button is pushed and for the vacuum to stabi­

lize.
Note the vacuum drop below -27 kPag (8 inches)
after each operation. The maximum allowable vac­
uum drop below -27 kPag (8 inches) after each oper­ ation is -3 kPag (3/4 inch). (Bypass the vacuum
storage tank if so equipped).
If the vacuum drop is more than -3 kPag (3/4 inch),
first recheck the tester for reading exactly -27 kPag
(8
inches). If correct, inspect the fit of the 7 port hose
connector plug on the push button switch. This plug
must be positioned all the way onto the 7 ports on
the push button switch.
CAUTION:
Do not use
lubricant
on the
switch ports
or
in the
holes
in the
plug,
as
lubricant
will
damage
the vacuum valve
in the
switch.
If it is
difficult
to
properly position connector plug
on the
switch
ports,
put a
drop
or two of
clean
water
in the
con­

nector plug holes. This
will
allow
the
plug
to
slide
completely
on the
switch ports.

If vacuum drop is now within limits, proceed with
the over-all performance test. If vacuum drop is still in excess of
-3
kPag (3/4 inch), remove 7 port connec­
tor from switch and seal port No. 6 with a finger to check source hose. Then remove prod from source
line and insert it alternately into each connector port
except No. 6 (Fig. 8).

Fig.
8
Vacuum
Tube
Assembly
Test
Note amount of vacuum drop below -27 kPag (8
inches) after each actuator has operated. If vacuum
test gauge comes back to -27 kPag (8 inches) at each of the 7 ports, the hoses and actuators are not leak­
ing. The control switch is faulty and must be re­
placed. If excessive vacuum drop shows up at one or
more ports in connector block, isolate faulty hose or actuator.
Inspect hose connections to the actuator involved.
Then test whether actuator or hose is at fault; use
the test hose on the actuator involved (Fig. 9).
A leak in a hose may be detected with vacuum test
set by running the fingers along the hose and watch­
ing vacuum gauge reading. The tube can be repaired
by cutting out the "leak" and inserting the tube ends into a 3 mm (1/8 inch) inside diameter rubber tube.
Wet the tube with water to aid assembly.
A vacuum drop in excess of 3 kPag (3/4 inch) below

-27
kPag (8 inches) will not interfere with engine op­
eration. A rough idle may occur. It can, however, in-

24 - 14
HEATING
AND AIR
CONDITIONING

•

Fig.
9
Vacuum
Actuator Test terfere with the proper operation of the air
conditioning and heating controls at high speeds and
during acceleration.
COMPRESSOR NOISE Noises that develop during air conditioning opera­
tion can often be misleading.
FOR EXAMPLE: What sounds like a failed front
bearing or connecting rod, may be caused by loose

bolts,
nuts, mounting brackets or a loose clutch as­ sembly.
Improper belt tension is also often the source of an
objectionable noise and can easily be mistaken for in­
ternal compressor troubles.
Drive belts are speed sensitive. That is, at different
engine speeds, and depending upon belt tension, belts
can develop unusual noises that are often mistaken
for mechanical problems within the compressor.
The adjustment procedures follows: (1) Select a quiet area for testing. Switch compres­
sor on and off several times to clearly identify com­
pressor noise. (2) Tighten all compressor mounting bolts, clutch
mounting bolt, clutch coil mounting screws and com­
pressor drive belts. Check that plumbing is not rub­
bing other parts. (3) Make sure that matched drive belts are in
equal tension. Replace any parts that are defective or
missing.
(4) Test the vehicle. If noise persists, continue
trouble shooting system for source of noise. Refer to A/C Compressor and Clutch Diagnosis
Charts.

CLUTCH COIL
TEST
(1) Verify battery state of charge (test indicator
should be green.)
(2) Connect an ammeter (0-10 ampere scale) in se­
ries with the clutch coil terminal. Use a voltmeter (0-20 volt scale) with clip leads measuring voltage
across the battery and A/C clutch.
(3) With A/C control in A/C mode and blower at
low speed, start the engine and run at normal idle.
(4) The A/C clutch should engage in 11 seconds af­
ter the start. The clutch voltage should be within 2
volts of the battery voltage. If the A/C clutch does not engage, check the fuse.
(5) The A/C coil is acceptable, if the current draw
is 2.0 to 3.7 amperes at 11.5 to 12.5 volts. The test
room temperature should be 18°C to 24°C (65°F to
75°F).
Where voltage is more than 12.5 volts, add
electrical loads as needed by increasing blower speed
and/or switching other electrical accessories on. If
coil current reads zero, the coil is open and should be
replaced. If the ammeter reading is 4 amperes or more, the coil is shorted and should be replaced. If
the coil voltage is not within 2 volts of the battery
voltage, check the circuit external to the clutch coil for excessive voltage drop and repair accordingly.
Refer to A/C Compressor and Clutch Diagnosis
Charts.

HEATING
AND AIR
CONDITIONING
24 -
A/C COMPRESSOR AND CLUTCH DIAGNOSIS

A/C
COMPRESSOR NOISY

?

COMPRESSOR
OFF
COMPRESSOR
ON

I

CLUTCH PULLEY
RUBBING
EVALUATE INSIDE
VEHICLE MODE- MAX
A/C

BLOWER-LOW
OUTLETS-OPEN WINDOWS-
CLOSED

EVALUATE INSIDE
VEHICLE MODE- MAX
A/C

BLOWER-LOW
OUTLETS-OPEN WINDOWS-
CLOSED

CLUTCH BEARING NOISY
MOUNTING

BOLTS
LOOSE
TIGHTEN

•

REMOVE
BELTS

RECHECK
RUBBING AND BEARING
NOISE
LOOSE

BELTS

ADJUST

*
»

CHECK
AIR
GAP
RESET
IF
NOT

0.406
-
0.787
mm (0.016-0.031 In)
BELT
INTERFERENCE

• I

BENT PULLEY

REPLACE
PULLEY AND
ARMATURE KNOCKING
OR

GRINDING NOISE
FROM

COMPRESSOR

_ *

DEFECTIVE COIL IF
SO

REPLACE REPLACE

COMPRESSOR



FRONT
ALIGNMENT PIN LOOSE
OR
OUT
OF

SPECIFICATION
REPLACE

COMPRESSOR
FRONT

COVER
COMPRESSOR
WONT
TURN

PROPERLY
CLUTCH ENGAGES BUT SLIPS
OR
SMOKES
CLUTCH SLIPPING LOW VOLTAGE AT CLUTCH

CHECK
WIRING,

SWITCHES,
CLUTCH
AMPERAGE
AND
GROUND

I

AMPERAGE

GREATER
THAN
5
AMPS
CLUTCH COIL PARTIALLY SHORTED

REPLACE
COIL

OIL/GREASE
ON

FRICTION
SURFACES

CHECK
SHAFT
SEAL
FELT

COIL SNAP RING
NOT
PROPERLY

INSTALLED
IF BEARING DEFECTIVE
REPLACE

PULLEY
AND
ARMATURE NOTE: APPLY PARKING
BRAKE
AND RUN
ENGINE
IN
NEUTRAL ONLY.

*
CLUTCH OR BELT SUPPING CAN BE
CAUSED
BY OVERCHARGED
SYSTEM
OR CONDENSER FAN
NOT
RUNNING. OIL SATURATED

FELT
REPLACE
COMPRESSOR
SHAFT SEAL ADJUST BELT
TENSION

REPLACE
IF

NECESSARY
CLUTCH
PULLEY RUBS ON COIL
COIL
MISMOUNTED

SEIZED

COMPRESSOR

T

REPLACE

COMPRESSOR

AND CLUTCH
ASSEMBLY

GREASE
PURGED
FROM
BEARING
REPLACE
CLUTCH
PULLEY
AND
ARMATURE

GREASE
PURGED

FROM
BEARING
REPLACE
CLUTCH
PULLEY
AND
ARMATURE

J9324-99

24 - 16 HEATING AND AIR CONDITIONING

A/C
COMPRESSOR AND CLUTCH DIAGNOSIS (CONT.)

COMPRESSOR
CLUTCH
WON'T
ENGAGE

f
f

NO
VOLTAGE
VOLTAGE
AT
AT CLUTCH CLUTCH
NORMAL

f t
OPEN FUSE FAULTY

GROUND

f
1
PUSHBUTTON SWITCH OPEN COIL
f
FAULTY

WIRING
REPLACE
COIL
f
r

POOR
VOLTAGE
AT

GROUND CLUTCH LOW

f

CHECK
WIRING

AND SWITCHES

f

CHECK
VOLTAGE
DROPS
FROM

CLUTCH TOWARD BATTERY
CYCLING SWITCH IF CONTACT OPEN

CHECK

REFRIGERANT
CHARGE

IF CHARGE
OK REPLACE SWITCH
COMPRESSOR
LEAKS
OIL OR REFRIGERANT
DEFECTIVE
CRANKSHAFT
SEAL

CARTRIDGE
DEFECTIVE
CRANKSHAFT
SEAL

PLATE

DEFECTIVE

SEAL
("O' RING),
FRONT
COVER,
REAR
COVER
DEFECTIVE

COMPRESSOR
THRU
BOLT

READ

COMPRESSOR

SERVICE
SECTION FOR REPAIR
DEFECTIVE

COMPRESSOR
BODY

REPLACE

COMPRESSOR

NOTE: APPLY PARKING BRAKE
AND RUN ENGINE
IN
NEUTRAL
ONLY.

•

HEATING
AND
AIR
CONDITIONING
24-17 REFRIGERANT SYSTEM SERWICE PROCEDURES

INDEX
page
Charging
the
System
19

Correcting
Low
Refrigerant
Level
.............
20
Discharging
the
System
. 19
Evacuating
the
System
19

REFRIGERANT

SAFETY
PRECAUTIONS

WARNING: EXTREME CARE MUST
BE
TAKEN
TO
PREVENT
ANY LIQUID
REFRIGERANT FROM COM­
ING
IN
CONTACT
WITH
THE
SKIN
AND
ESPE­

CIALLY
THE
EYES.
ALWAYS WEAR SAFETY
GOGGLES WHEN SERVICING
ANY
PART
OF
THE
REFRIGERANT SYSTEM.
IF EYE
CONTACT
IS

MADE,
APPLY
A
FEW
DROPS
OF
MINERAL
OIL
TO

THE
EYES
AND
FLUSH
WITH
WATER
FOR
SEV­
ERAL MINUTES.
SEEK
MEDICAL
ATTENTION
IMME­
DIATELY.

The refrigerant used
in the air
conditioner system
is Refrigerant-12 (R-12).
R-12 is
nonexplosive, non­
flammable, non-corrosive,
has
practically
no
odor
and
is heavier than
air.
Although
it is
classified
as a
safe
refrigerant, certain precautions must
be
observed
to

protect
the
parts involved
and the
person
who is

working
on the
unit. Liquid
R-12, at
normal atmo­ sphere pressures
and
temperatures, evaporates
so

quickly that
it has the
tendency
to
freeze anything
it
contacts.

WARNING:
TO
AVOID
A
DANGEROUS EXPLOSION,
NEVER
WELD
OR
STEAM CLEAN NEAR
AIR
CON­

DITIONING
LINES
OR
COMPONENTS.
DO NOT

HEAT
R-12
ABOVE
52°C (125°F)
BECAUSE
THE

CAN
MAY
EXPLODE.

The
R-12 in the
system
is
always under pressure.
Because
the
system
is
tightly sealed, heat applied
to
any part could cause this pressure
to
build
up
exces­sively.

WARNING: LARGE AMOUNTS
OF
REFRIGERANT
RELEASED
IN A
CLOSED WORK AREA
WILL
DIS­
PLACE
THE
OXYGEN
AND
CAUSE SUFFOCATION.
ALWAYS
MAINTAIN
GOOD
VENTILATION
SUR­ ROUNDING
THE
WORK AREA.

R-12
gas,
under normal conditions,
is
non-poison­

ous.
The
discharge
of R-12 gas
near
an
open flame
page
Pressure Gauge
and
Manifold
Assembly
18

Refrigerant
. 17

Refrigerant
Leak Repair Procedure
20

Service Precautions
. 17

can produce
a
very poisonous
gas
called phosgene.
Phosgene
is
generated when
a
flame-type leak detec­
tor
is
used.

CAUTION:
When charging
an A/C
system always
keep
the
tank
in an
upright position.
If the
tank
is

on
its
side
or
upside down,
liquid
refrigerant
will

enter
the
system
and may
damage
the
compressor.

In most instances, moderate heat
is
required
to

bring
the
pressure
of the
refrigerant above system
pressure when charging
or
adding refrigerant.
A

bucket
or
large
pan of hot
water,
not
over 52°C (125°F),
is all the
heat required
for
this purpose.
Do

not heat
the
refrigerant container with
a
blow torch
or
any
other means that would raise
the
temperature and pressure above this temperature.

CAUTION:
Do not
allow
liquid
refrigerant
to
touch
bright
metal.

Refrigerant will tarnish bright metal
and
chrome
surfaces. Avoid splashing
the
refrigerant
on any
sur­

face.
Refrigerant
in
combination with moisture
is

very corrosive
and can
cause extensive damage
to all

metal surfaces.

RECYCLING
(R-12) refrigerant
is a
chloroflorocarbon
(CFC)
that
can contribute
to the
depletion
of the
ozone layer
in

the upper atmosphere. Harmful radiation from
the
sun
is
filtered
out by the
ozone.
To
assist
in
protect­
ing
the
ozone layer, Chrysler Corporation recom­
mends that
an
(R-12) refrigerant recycling device
that meets
SAE
standard
J1991 be
used. Contact
an
automotive service equipment supplier
for
refriger­
ant recycling equipment that
is
available
in
your
area. Refer
to the
operating instructions provided
with
the
recycling equipment
for
proper operation.

SERVICE
PRECAUTIONS
Kinks
in the
refrigerant tubing
or
sharp bends
in

the refrigerant hose lines will greatly reduce
the ca­
pacity
of the
entire system. High pressures
are
pro­duced
in the
system when
it is
operating. Extreme
care must
be
exercised
to
make sure that
all
connec­
tions
are
pressure tight. Dirt
and
moisture
can
enter

24 - 18
HEATING
AND AIR
CONDITIONING

• the system when it is opened for repair or replace­
ment of lines or components, The following precau­
tions must be observed.
The system must be completely discharged before
opening any fitting or connection in the refrigeration
system. Open fittings with caution even after the
system has been discharged. If any pressure is no­
ticed as a fitting is loosened, allow trapped pressure
to bleed off very slowly.
Keep the radius of all bends at least 10 times the
diameter of the hose. Sharper bends will reduce the
flow of refrigerant. The flexible hose lines should be routed so they are at least 80 mm (3 inches) from the exhaust manifold. It is a good practice to inspect all
flexible hose lines at least once a year to make sure they are in good condition and properly routed.
Unified plumbing connections with aluminum-N-
gaskets cannot be serviced with O-rings. These gas­
kets are not reusable and do not require lubrication
before installing.
The use of correct wrenches when making connec­
tions is very important. Improper wrenches or im­
proper use of wrenches can damage the fittings.
The internal parts of the refrigeration system will
remain in a state of chemical stability as long as
pure-moisture-free R-12 and refrigerant oil is used. Abnormal amounts of dirt, moisture or air can upset
the chemical stability and cause operational troubles or even serious damage if present in more than
minute quantities.
When it is necessary to open the refrigeration sys­
tem, have everything needed ready so the system
will not be left open any longer than necessary. Cap
or plug all lines and fittings as soon as they are
opened to prevent the entrance of dirt and moisture. All tools, including the refrigerant dispensing man­
ifold, the manifold gauge set and test hoses should be
kept clean and dry.

PRESSURE
GAUGE AND MANIFOLD
ASSEMBLY
Pressure Gauge and Manifold Assembly Tool
C-3740-A is the most important tool used to service
the air conditioning system (Fig. 1).
COMPONENTS

E¥AP0RAT0R SUCTiOl GAUiE
The left side of the manifold set is calibrated to
register 0 to -100 kPag (0 to 30 inches of vacuum).
The gauge will also register 0 to 1 000 kPag (0 to 150 psig). This gauge is connected to the suction ser­
vice port of the compressor. A special service port adapter, supplied with the gauge set, provides the
means of connecting the gauge set manifold hose to
the service port. When the adapter is installed at the
port and tightened, the stem of the valve in the ser­ vice port is depressed, opening the service port valve.
COMPOUND GAUGE
HIGH
SIDE

Fig.
1
Pressure
Gauge and Manifold
Assembly
Tool
C-3740-A
DISCHARGE
PRESSURE
GAUGE

The center of the manifold set is calibrated to reg­
ister 0-2 100 kPag (0-300 psig). For all tests this
gauge is connected to the discharge service port of
the system. The needle valve, located below the dis­ charge pressure gauge, is used to damp out gauge
needle oscillations so that accurate readings can be
obtained.

CENTER
MANIFOLD
OUTLET
This outlet provides the necessary connection for a
long service hose. This hose is used:
• To discharge the system.
• For a vacuum pump to pull a vacuum before charging the system.
• For connecting the supply of refrigerant when charging the system.

MANIFOLD GAUGE WALWES
This valve should be closed when connecting the
gauge set manifold to the service ports of the com­
pressor. The suction gauge valve at the left is opened to provide a passage between the suction gauge and
the center manifold outlet. The discharge gauge
valve at the right is opened to provide a passage be­
tween the discharge pressure gauge and the center manifold outlet.
SERVICE VALVES The discharge (high pressure) and inlet (suction)
service valves are used for diagnosis, charging, dis­
charging and evacuating the system.
CONNECT PRESSURE GAUGE AND MANIFOLD
ASSEMBLY
Remove the protective caps from the service valve
gauge ports and valve stems.
Close both of the hand valves on the gauge mani­
fold set.

•

HEATING
AND
AIR
CONDITIONING
24 - 19
Connect
the
compound gauge hose
to the
compres­
sor suction service valve gauge port (low-side).
Connect
the
high pressure gauge hose
to the
dis­
charge service valve gauge port (high-side). Purge
air
from
the
high side test hose
by
opening
the high side hand valve
on the
manifold
for 3 to 5
seconds.
The
center connection
on the
manifold must
be open.
Purge
air
from
the low
side test hose
by
opening
the
low
side hand valve
on the
manifold
for 3 to 5
seconds.
The
center connection
on the
manifold must
be open.
The
air
conditioning system
may be
operated with
the gauge manifold assembly connected
in
this man­
ner.
The
gauges will indicate respective operative
pressures.

DISCHARGING
THE SYSTEM
Since
the air
conditioning refrigerant system
is

pressurized,
it
will
be
necessary
to
completely dis­ charge
the
system before replacing
any
refrigerant
components.
The
procedure
is as
follows: (1) Install gauge
set as
described under manifold
gauge
set
installation. Make sure
the
gauge
set

valves
are
closed before attaching
the
hoses
to the re­

frigerant system. (2) Install
a
long hose
to the
manifold gauge
set

connector.
Run
this hose
to the oil
collector
can
near
the shop exhaust system. A good
oil
collector
can may be
made from
a
large
empty coffee
can
with
a
plastic
top.
Slit
the
plastic
top
in the
form
of a Y to
make
an
entrance
for the
refrigerant hose
and
exit
for the gas.
(3) Open
the
compressor discharge
and
suction line
pressure valves
and
discharge
the
refrigerant into
the
oil
collector
can.
Watch
to
make sure
the
hose does
not
blow
out of the
collector
can.
(4) When
the
system
has
been completely dis­
charged, measure
the
amount
of oil
collected
in the

can.
The
amount
of oil
measured should
be
added
to

the refrigerant system before
it is
charged. Discard
the used
oil. Add new oil.

EVACUATING
THE SYSTEM
Whenever
the
system
has
been opened
to the
atmo­
sphere,
it is
absolutely essential that
the
system
be

evacuated
to
remove
all the air and
moisture.
Air in

the refrigerant system causes high compressor dis­ charge pressures,
a
loss
in
system performance,
and

oxidation
of the
compressor
oil
into
gum and
varnish.
Moisture
in the
refrigerant system
can
cause
the ex­

pansion valve
to
malfunction. Under certain condi­
tions
it can
react with
the
refrigerant
to
form destructive acids.
It is
necessary
to
adhere
to the
fol­
lowing procedure
to
keep
air and
moisture
out of the
system. (1) Connect
the
manifold gauge
set to the
compres­
sor
and
long test hose from manifold gauge
set
center
connection
to
Vacuum Pump Tool C-4289. (2) Open both manifold gauge
set
valves.
(3) Start
the
vacuum pump
and
operate until
the

evaporator suction gauge registers
at
least
-88
kPag (26 inches
of
vacuum).
If at
least
-88
kPag
(26
inches
of vacuum) cannot
be
obtained, either
the
system
has

a leak
or the
vacuum pump
is
defective. Check
the

vacuum pump.
If the
pump proves
to be
functioning
properly,
the
system
has a
leak. Charge
the
system
with
1
pound
of
refrigerant. Locate
and
repair
all
leaks.
Discharge
the
refrigerant
and
evacuate
the
system.
(4) Continue
to
operate
the
pump
for at
least
5

minutes.
(5) Close manifold valves. Turn
off the
vacuum
pump
and
observe evaporator suction gauge
for 2
minutes.
The
vacuum level should remain constant.
If
the
vacuum level falls
off, the
system
has a
leak. Charge
the
system with
450 g (1
pound)
of
refriger­
ant. Locate
and
repair
all
leaks. Discharge
the
sys­
tem
and
repeat evacuation procedure.

CHARGING
THE
SYSTEM
The refrigerant system must have been evacuated
using
the
previous procedure before charging. Charge
using only
R-12
refrigerant.
R-12 is
available
in
bulk
tanks
or 437 g (14 oz.)
cans. The special refrigerant dispensing manifold per­
mits charging
3
cans
of
refrigerant
at a
time. When
using disposable cans
of
this type, carefully follow
the
can
manufacturers instructions.

WARNING: NEVER USE THESE CANS
TO
CHARGE
INTO
THE
HIGH
PRESSURE SIDE
OF
THE
SYSTEM

(COMPRESSOR
DISCHARGE PORT)
OR
INTO
A
SYSTEM
THAT
IS AT
HIGH
TEMPERATURE.
THE
HIGH
SYSTEM PRESSURES COULD
BE
TRANS­

FERRED
INTO
THE
CHARGING
CAN
CAUSING
IT

TO EXPLODE.

Keep
the
refrigerant manifold valves capped when
not
in use.
Keep
a
supply
of
extra refrigerant-can-to
refrigerant-manifold gaskets
on
hand
so the
gaskets can
be
replaced periodically. This will insure
a
good
seal without excessive tightening
of the can or the

manifold nuts.
(1) Attach center hose from manifold gauge
set to

refrigerant dispensing manifold. Turn refrigerant manifold valves completely counterclockwise
so
they are fully open. Remove protective caps from refriger­
ant manifold.
(2) Screw refrigerant cans into manifold.
Be
sure
manifold-to-can gasket
is in
place
and in
good condi­
tion. Tighten
can and
manifold nuts
to 9.5 N»m (7 ft.
lbs.) torque.