1973 OPEL GT-R air conditioning

98-26 1973 OPEL SERVICE MANUAL
greater than the opposing pressure in the power ele-
ment. Therefore, the valve remains closed. When the
compressor is started, it will reduce the pressure and
temperature of the refrigerant in the cooling coil to
a point where the vapor pressure in the power ele-
ment becomes the stronger. The seat then moves off
the orifice and liquid starts to flow through the valve
orifice into the cooling coil.
The purpose of the power element is to help deter-
mine the quantity of liquid that is being metered into
the cooling coil. As the temperature of the low pres-
sure line changes at the bulb, the pressure of
the
vapor in the power element changes, resulting in a
change of the position of the seat. For example, if the
cooling coil gets more liquid than is required, the
temperature of the low pressure line is reduced and
the resultant lowering of the bulb temperature
reduces the pressure of the vapor in the power ele-
ment, allowing the seat to move closer to the orifice.
This immediately reduces the amount of liquid leav-
ing the valve. Under normal operation, the power
element provides accurate control of the quantity of
refrigerant to the cooling coil.
To employ our tire pump analogy once more for
clarity, it is the same situation that would exist if you were inflating a tire with a very slow leak. Providing
you pumped the air into the tire as fast as it leaked
out, you would be able to maintain pressure even
though the air would merely be circulating through the tire and leaking out through the puncture.
To Sum Up
So far, we’ve discussed only what each unit in an air
conditioning system does. We’ve learned that the
evaporator is the unit in which liquid refrigerant
soaks up heat from the air, the compressor is a pump
for squeezing this heat out of the vapor, the con-
denser is a radiator for getting rid of the heat, and the
thermostatic expansion valve is a device for regulat-
ing the pressure on the refrigerant. Now, let’s
find
out how the temperature of the cooled air is con-
trolled.
METHOD OF TEMPERATURE CONTROL
To achieve temperature control, the compressor is
run intermittently, automatically turning on and off
as necessary to maintain proper temperature.
Thermostatic Switch
The compressor can be started and stopped au-
tomatically through the use of an electro-magnetic
clutch and a thermostat affected by variations of temperature.
The job is usually done by a gas bulb thermostat (Fig.
9B-21).
Figure 9B-21 Thermostatic Switch Schematic
With the gas bulb type of thermostat, a highly expan-
sive gas is sealed into a metallic bulb which is located
in the air stream as it leaves the evaporator. A small
tube leads from the bulb to a bellows operated switch. As air temperature rises, the gas inside the
bulb expands, travels through the tube to the bellows
and closes the electrical switch that engages the com-
pressor clutch.
Of course, as soon as the compressor starts running,
the temperature begins to go down. As the air being
cooled gets colder, the gas in the thermostat bulb
begins to reduce the pressure on the switch bellows.
This
Ilips “off’ the switch and disengages the com-
pressor clutch.
REFRIGERANTS
No matter how scientifically refrigerating machinery
is built or how
efftciently it runs, it alone cannot
remove heat. The only thing that carries heat out of
a refrigerator cabinet or an automobile is the sub-
stance we call the refrigerant.
There are many refrigerants known to man. In fact,
any liquid that can boil at temperatures somewhere
near the freezing point of water can be used.
But a boiling point below the temperature at which
ice forms is not the only thing that makes a good
refrigerant. A refrigerant should also be non-
poiso-
nowand non-explosive to be safe. Besides that, we
want a refrigerant that is non-corrosive and one that
will mix with oil.
Since Nature did not provide an ideal refrigerant,
chemists went to work to see if they could do any
better. They did! But it wasn’t as simple as that.
At first, they tried to improve existing natural refrig-
erants. But after exploring innumerable trails along

REFRIGERANT COMPONENTS ALL MODELS99.27that line, they still hadn’t gotten anywhere. So, they
started from scratch and juggled molecules around
to make an entirely new refrigerant. Eventually they
succeeded by remodeling the molecules in carbon
tetrachloride. This is the same fluid that is used in
fire extinguishers and dry-cleaners’ solvents.
From this fluid, the chemists removed two chlorine
atoms and replaced them with two fluorine atoms.
This newly-formed fluid carried the technical chemi-
cal name of dichlorodifluoromethane. Today, we
know it as Refrigerant-12 or R-12.
Fluorine is an extremely temperamental substance.
Under most conditions it is toxic and highly corro-
sive, and after is is manufactured, it has to be stored
in special containers because it will eat through glass
and will dissolve most metals in short order.
Despite its rambunctious character though, fluorine
is completely tamed when it is combined with the
other substances that go to make up the refrigerant.
Each is non-toxic, non-inflammable, non-explosive,
and non- poisonous; however, breathing large quan-
tities of R-12 should be avoided.
Pressure. Temperature Relationship of R-12A definite pressure and temperature relationship ex-
ists in the case of liquid refrigerants and their satu-
rated vapors. Increasing the temperature of a
substance causes it to expand. When the substance is
confined in a closed container, the increase in tem-
perature will be accompanied by an increase in pres-
sure, even though no mechanical device was used.
For every temperature, there will be a corresponding
pressure within the container of refrigerant. A table
of the temperature-pressure relationship of R-12 is
presented below. Pressures are indicated in gauge
pressure, either positive pressure (above atmos-
pheric) m pounds or negative pressure (below atmos-
pheric) in inches of vacuum.
“F-40
-35
i#Pressure
11.0*
8.3*
“F
50
50#Pressure
46.1
52.0
-30~
5.5*6057.7
-252.3*6s67 7__.
-200.6
io70.1
-152.4
76.9
-104.584.1
1;6.8 9.2tz99.6 91.71;
11.8 14.712116.9 108.1
1517.7105126.2
2021.1110136.0
2524.6115146.5
3028.5120157.1
;:
30.1
125167.5
32.6
131)179n
4037.0
4541.7*Inches of Vacuum.-. _.-
1402045
150232.0Thus if a gauge is attached to a container of R- 12 and
the room temperature is 70 degrees, the gauge will
register 70 psi pressure; in a 100 degrees room the
pressure will be 117
ps~
AIR CONDITIONINGBecause air conditioning has always been very
closely allied with mechanical refrigeration, most of
us are apt to think of it only as a process for cooling
room air.
But true air conditioning goes beyond the mere cool-
ing of the air. It controls the humidity, cleanliness,
and circulation of the air as well.
Whenever it gets warm and muggy in the summer-
time, someone is almost sure to say, “It’s not the heat
it’s the humidity.” But that is only partly right.
Actually it is a combination of the two that makes us
feel so warm temperature alone is not the only
thing that makes us uncomfortable.
Humidity is nothing more nor less that the moisture
content of the air. To a certain extent, it is tied in
with the temperature of the air. Warm air will hold
more moisture than will cold air. When air contains
all the moisture it can hold, we say it is saturated,
and the relative humidity is 100 percent. If the air
contains only half as much water as it could possibly
hold at any given temperature, we say that the rela-
tive humidity is 50 percent. If it contains only a fifth
of its maximum capacity, we say that the relative
humidity is 20 percent and so on. This amount
of water vapor, or relative humidity, affects the way
we perspire on hot days.
Nature has equipped our bodies with a network of
sweat glands that carry perspiration to the skin
sur-faces. Normally, this perspiration evaporates and, in
doing so, absorbs heat just like a refrigerant absorbs
heat when it is vaporized in a freezer. Most of the
heat thus absorbed is drawn from our bodies, giving
us a sensation of coolness. A drop of alcohol on the
back of your hand will demonstrate this principle
very convincingly. Because it is highly volatile, al-
cohol will evaporate very rapidly and absorb quite a
bit of heat in doing so, thereby making the spot on
your hand feel unusually cool.
The ease and rapidity with which evaporation takes
place, whether it be alcohol or perspiration, governs
our sensation of coolness and to a certain extent,
independently of the temperature. Of even more im-
portance, the ease and rapidity of the evaporation are
directly affected by the relative humidity or com-
parative dampness of the air. When the air is dry,
perspiration will evaporate quite readily. But when
the air contains a lot of moisture, perspiration will
evaporate more slowly; consequently less heat is car-
ried away from our body.

9B-28 1973 OPEL SERVICE MANUAL
Thus, from the standpoint of comfort, complete air
conditioning should control the relative humidity of
the air as well as its temperature.
By reducing the humidity, we sometimes can be just
as “cool” in a higher room temperature than other-
wise would be comfortable. Laboratory tests have
shown that the average person will feel just as cool
in a temperature of 79 degrees when the relative
humidity is down around 30 percent as he will in a
cooler temperature of 72 degrees with a high relative
humidity of 90 percent.
There are practical limits though within which wemust stay when it comes to juggling humidity. For
human comfort, we can’t go much below a relative
humidity of 30 percent because anything lower than
that would cause an unpleasant and unhealthy dry-
ness in the throat and nasal passages.
Summertime temperatures of 85 degrees sometimes
bring with them relative humidities around 75 to 80
percent. Some coastal cities have relative humidities
averaging as high as 87 percent. To gain maximum
human comfort, an air conditioning system should
cool the air down and reduce the humidity to com-
fortable limits.
The cooling job usually is done just as it is in a
refrigerator. A compressor sends refrigerant through
a chilling unit where it absorbs heat. The heat is
drawn out of the air which circulates through the
chilling unit. Along with the cooling job it does, the
evaporator unit also removes much of the moisture
from the air. Everyone is familiar with the sight of
thick frost on the freezer of a refrigerator. That frost
is simply frozen moisture that has come out of the
air.
Figure 99.22 Condensation
The evaporator unit in an air-conditioning system
does the same thing with this one exception. Becauseits temperature is above the freezing point, the mois-
ture does not collect in the form of ice or frost.
Instead, the moisture remains fluid and drips off the
chilling unit. This action is similar to what occurs on
the cool bathroom mirror when a hot shower is
turned on (Fig. 9B-22). A further advantage of airconditioning is that dust and pollen particles are
trapped by the wet surfaces of
.the evaporator core
and then drained off with the condensed moisture.
This provides very clean, pure air for breathing, and
is of great benefit to those who suffer from asthma
or ahergies such as hay fever.
Basic Refrigeration CycleLet’s review the basic refrigeration cycle. Keep this
basic cycle in mind because knowledge of the cycle,
knowledge of the particular system you are working
on and proper use of the gauges will permit quick,
accurate diagnosis of problems as they arise.
Any refrigeration system takes advantage of the
principles just described. The air conditioning sys-
tem illustrated in Fig. 9B-23 contains
five basic parts;
a compressor, a condenser, a receiver, an expansion
valve and an evaporator. Assuming R-12 as our re-
frigerant, let us follow through the refrigeration cy-
cle.Refrigerant gas under low pressure is drawn into the
compressor where it is compressed to a high pres-
sure. During compression, the refrigerant gas is
heated. When sufficient pressure is built up, the hot
gas passes into the condenser where it cools by giving
off heat to the air passing over the condenser sur-
faces.As the refrigerant gas cools, it condenses into a liquid
at high pressure and accumulates in the receiver. The
high pressure liquid refrigerant passes to the expan-
sion valve at the entrance to the evaporator. At the
valve orifice the pressure is lowered and the refriger-
ant enters the evaporator core as a low pressure liq-
uid. When the refrigerant is exposed to the lower
evaporator pressure, it begins to boil and is changed
to a vapor state. As the refrigerant passes through
the evaporator, it continues to boil by absorbing heat
from the air passing over the evaporator surfaces
until it is completely vaporized. From the evaporator
the cool low pressure refrigerant gas is drawn back
to the compressor and the cycle repeated.
Thus the air passing over the evaporator surfaces is
cooled simply by giving up heat to the refrigerant
during the boiling process.
CHEMICAL INSTABILITY AND REFRIGERATING
SYSTEM FAILURESA sealed refrigerating system is a complex physical-
chemical combination which is designed for stability

REFRIGERANT COMPONENTS ALL MODELS99.29
1 REFRIGERANT LEAVES COMPRESSOR
AS A HIGH PRESSURE-HIGH
TEMPERATURE VAPOR
REFRIGERANT RETURNS TO
COMPRESSOR AS LOW PRESSURE VAPOR
EXPANSION VALVE5 HEAT REMOVED
FROM AIR VAPORIZES
LOW PRESSURE
LIQUID REFRIGERANT
4 HIGH PRESSURE‘JQUID CHANGES
TO LOW PRESSURE
LIQUID AT THIS
POINT
2 UPON REMOVAL OF HEAT
VAPOR BECOMES HIGH
PRESSURE LIQUID REFRIGERANT3 LIQUID REFRIGERANT IS STORED
HERE UNTIL NEEDED
98*II
Figure 98-23
Basic
Refrigeration Cyclewithin certain operating limits. If these limits are
exceeded, many physical and chemical reactions oc-
cur. Since the results of these reactions within the
system cannot be easily removed, they build up into
a constantly accelerating vicious circle to eventually
fail the system.is allowed to enter the system, it can start a chain of
chemical reactions which upsets stability and inter-
feres with the operation of the unit.
Metals
CHEMICAL INGREDIENTS OF AN AUTOMOTIVE
AIR CONDITIONING SYSTEMAll systems involve metals, refrigerant, and oil which
are basic and essential. The desiccant, or dehydrating
agent, and another chemical ingredient, synthetic
rubber, makes it even more complex.
All of these ingredients have chemical properties
which are entirely different from each of the others.
In spite,of these differences, by proper selection of
the ingredients and controlled processes in manufac-
ture, plus careful servicing procedures they can be
combined so that they “live together” to provide
many years of satisfactory and trouble-free operat-
ion.If, however, only one undesirable element is added orIn most cases, metals contribute to the decomposi-
tion of R-12 and oil in varying amounts. All are
attacked by acids.
Each of the metals in common use in a system has
been selected for a specific reason; heat conductivity,
durability, strength, and chemical composition.
Under favorable conditions, the amounts of decom-
position of Refrigerant-12 and oil produced by these
metals is negligible and allowable. However, if un-
desirable substances are added and the temperature
is increased, the rate of decomposition and the pro-
duction of harmful acids increases proportionally.
RefrigerantThe chemical properties of refrigerants are very im-
portant factors in the stability of a system since the

REFRIGERANT COMPONENTS ALL MODELS99- 33
That the attraction of the drying material for mois-
ture is so powerful that if the receiver is left open,
moisture will be drawn in from the outside air.
That just one drop of water added to the refrigerantwill start chemical changes that can result in corro-
sion and eventual breakdown of the chemicals in the
system. Hydrochloric acid is the result of an R-12
mixture with water.
That the smallest amount of air in the refrigeration
system may start reactions that can cause malfunc-
tions.
That the drying agent in the receiver-dehydrator is
Activated Silica Alumina (silica-gel).
That
the inert gas in the expansion valve capillary
line is carbon dioxide.
DESCRIPTION OF AIR CONDITIONING
COMPONENTS
Compressor
The compressor is located in the engine compart-
ment. The purpose of the unit is to draw the low
pressure,gas from the evaporator and compress this
gas into a high temperature, high pressure gas. This
action will result in the refrigerant having a higher
temperature than the surrounding air.
The
cortipressor is of basic double action piston de-
sign. Three horizontal double acting pistons make up
a six cylinder compressor (See Figure
9B-162). The
pistons operate in
l-1/2 inch bore and have a l-1/8
inch stroke. A
wash plate keyed to the shaft drives
the pistons. The shaft is belt driven through a mag-
netic clutch and pulley arrangement. An oil pump
mounted at the rear of the compressor picks up oil
from the
botto’m of the compressor and lubricates the
bearings’and other internal parts of the compressor.
Reed type valves at each end of the compressor open
or close to control the flow of incoming and outgoing refrigerant. Two gas tight passages interconnect
chambers of the front and rear heads so that there is
one common suction port, and one common dis-
charge port. The internal parts of the compressor
function, as follows:
1. Suction Valve Reed Discs and Discharge Valve
Plates
_ The two suction valve reed discs and two
discharge valve plates (see Figure
9B-25) operate in
a similar but opposite manner. The discs are com-
posed of three reeds and function to open when the
pistons are on the intake portion of their stroke
(downstroke), and close on the compression stroke.
The reeds allow low pressure gas to enter the cylin- ders. The discharge valve plates also have three
reeds, however, they function to open when the pis- tons are on the compression portion of their stroke
(upstroke), and close on the intake stroke. High pres-
sure gas exits from discharge ports in the discharge
valve plate. Three retainers riveted directly above the
reeds on the valve plate serve to limit the opening of
the reeds on the compression stroke.
SUCTION VALVE
DISCHARGE-VALVE PLATES
Figure
98-25 - Compressor Suction Valve Reed Discs
and Discharge Valve Plates
2. Front and Rear Heads - The front and rear heads
(Figure
9B-26) serve to channel the refrigerant into
and out of the cylinders. The front head is divided
into two separate passages and the rear head is di-
vided into three separate passages. The outer passage
on both the front and rear heads channels high pres-
sure gas from the discharge valve reeds. The middle
passage of the rear head also contains the port open-
ing to the superheat switch cavity. This opening in
the rear head permits the superheat switch to be
affected by suction gas pressure and suction gas tem-
perature for the operating protection of the compres-
sor. The inner passage on the rear head houses the
oil pump inner and outer rotors. A Teflon sealing
material is bonded to the sealing surfaces separating
the passages in the rear head.
“0” rings are used to
affect a seal between the mating surfaces of the heads
and the shell. The front head suction and discharge
passages are connected to the suction and discharge
passages of the rear head by a discharge tube and
suction passage in the
body of the cylinder assembly.
A screen located in the suction port of the rear head
prevents foreign material from entering the circuit.
3. Oil Pump
- An internal tooth outer rotor and
external tooth inner rotor comprise the oil pump.
The pump works on the principle of a rotary type pump. Oil is drawn up from oil reservoir in underside
of shell through the oil inlet tube (see Figure
9B-27)

98-36 1973 OPEL SERVICE MANUALSPACER
17
RETAINER
RING
c Q
CLUTCHCOIL 8HOUSINGARING TO HEADTAINER RING
SHAFT NUT
CLUTCH DRIVEN
PLATE
BEARING TO PULLEYPULLEY BEARIN
RETAINER RINGCOIL 8HOUSING
CLUTCH DRIVEPLATIRETAINER RING
AND PULLEY ASSEMBLY
Figure 98-32
Magnetic Clutch and Pulley Assemblyis tack-welded to the inside of the shell. In addition,
an oil drain screw and gasket are located on the side
of the reservoir and are provided for draining or
adding of oil to system. To add oil, compressor must
be removed from car. The necessity to add oil should
only be required when the system has ruptured vio-
lently and oil has been lost along with refrigerant.
Under controlled conditions or slow leak conditions
it is possible to loose only a small amount of oil with
the refrigerant gas. The serial number, part or model
number, and rating of the compressor is stamped on
name plates located on top of shell.
12. Magnetic Clutch and Pulley Assembly
- The
magnetic clutch and pulley assembly (see Figure 9B-
32) together transmit power from the engine crank-
shaft to the compressor. The magnetic clutch is
actuated when the air conditioning temperature
switch and the fan switch located on the evaporator
cover assembly are closed. When the switches are
closed, the coil sets up a magnetic field and attracts
the armature plate (movable element of the clutch
driven plate). The armature plate portion of the
clutch driven plate moves forward and contacts the
friction surface of the pulley assembly, thereby me-
chanically linking the compressor to the engine. The
compressor will operate continuously whenever the
air conditioner clutch compressor switch and the fan
switch are closed. When one or both of the switches
are open the armature plate will be released due to
spring tension and move away from the pulley as-
sembly. This allows the pulley to rotate without driv-
ing the shaft. It should be noted that if the air
conditioner system was in use when the engine was
turned off, the armature plate may remain in contact
with the pulley due to residual magnetism. When the
engine is started the armature plate will separate
from the pulley assembly. The coil is rated at 3.85
ohms (85 degrees F.) and will draw 3.2 amperes at
12 volts D.C.Condenser
The condenser which is made of aluminum is locatedIN:ET
DESICCANT.
RECEIVERDEHYDRATOR
ASSEMBLY
FILTER
SCREEN
Figure 98-33 Receiver Dehydrator Assembly

98.40 1973 OPEL SERVICE MANUAL
2. Interconnect manifold and gage set (J-5725-01),
gage charging lines (J-5418) and gage adapters
(J-5420) to air conditioning system as shown in Figure
9B-40.3. Place transmission in “Park” for automatics and
in neutral for manuals. Apply hand brake.
4. Turn blower switch to the “Hi” position.
5. Turn temperature switch to “Max” position.
6. Run engine at 2000 RPM for ten (10) minutes with
car doors and windows closed and the hood up. Place
a high volume industrial type fan in front of radiator
if head pressure should exceed 250 psi and also at
high ambients to bring the pressures to within the
limits specified in the Functional Charts in Division
V.In the case of the Opel 1900 and the Manta, a ther-
mometer should be placed in a position to read the
temperature of the air discharging from the right-
hand A/C outlet. In case of the GT, a thermometer
should be placed in a position to read the tempera-
ture of the air discharging from the left-rear A/C
outlet.
HEATER-AIR CONDITIONER REFRIGERANT
CIRCUIT TROUBLE DIAGNOSIS GUIDE
Insufficient Cooling (Check Air Flow)
Normal Air Flow (Inspect system for visual defects.
Run functional tests.)
Discharge Air
- Normal Temp Check for air leaks
through dash, car body, windows, or from heater or
ventilators.
Discharge Air
- High Temp Check sight glass for
foaming and compressor clutch for engagement.
No Compressor Clutch Engagement Check connec-
tions at clutch switch, harness connectors, and check
clutch switch.
No Foaming Compare evaporator pressure to that
on functional test table.
Foaming System is probably low on refrigerant.
Check for leaks, repair, evacuate, and charge. If
foaming still occurs, check for restriction in refriger-
ant lines between condenser and receiver dehydrator.
Evaporator Pressure Normal Compare head pres-
sure to pressure on functional test table.
Evaporator Pressure Low Ice may be forming on
evaporator. Low volume of air discharging at A/C
outlet after system has been running above idle con-dition
,for approximately 15-30 min.utes. Discharging
air gradually elevating in temperature. Check expan-
sion valve. If valve isn’t permitting flow of liquid,
this will be indicated by a warm pipe out of the
evaporator. This may be caused by: 1) Clogged or
Plugged inlet screen in the expansion valve; 2)
Broken capillary line; or 3) Discharged temperature
bulb. If the valve is okay, the pipe out of the evapora-
tor will be cold.
Evaporator Pressure High Check the expansion
valve to determine if themobulb is making good con-
tact and is properly insulated. Operate engine at 2000
RPM with maximum air conditioning setting. If
evaporator pressure remains high, feel suction line.
If line feels frosty or extremely
(cold with relative
high ambient conditions, then partially cover the
condenser to obtain head pressures from 265 psi to
280 psi maximum. If evaporator pressure rises above
30 psi, change the expansion valve.
Also, check if compressor may be the cause due to
some internal or external mechanical trouble which
prevents reduction of pressure. Check for external
troubles, slipping belt, bad clutch and/or pulley, or
improper clutch engagement, before investigating
the compressor internally.
Head Pressure High Check for the following: Con-
denser air flow low, air in system, excessive refriger-
ant in system, restriction in condenser.Head.PressureLowRestriction in flow of refrigerant
to evaporator, or expansion valve plugged or defec-
tive.
Low Air Flow (Check blower operation and
evaporator. Check operation of controls.)
Ice BIocking Evaporator Run functional test. If
evaporator pressure is low, ice may form on evapora-
tor and reduce air flow.
Evaporator Pressure Low Ice may be forming on
evaporator. Low volume of air discharging at A/C
outlet after system has been running above idle con-
dition for approximately 15-30 minutes. Discharging
air gradually elevating in temperature. Check expan-
sion valve. If valve isn’t permitting flow of liquid,
this will be indicated by a warm pipe out of the
evaporator. This may be caused by: 1) Clogged or
plugged inlet screen in the expansion valve; 2)
Broken capillary line, or 3) Discharged temperature
bulb. If the valve is okay, the pipe out of the evapora-
tor will be cold.BlowerNot OperatingCheck for the following: Fuse
blown, blower switch defective, wire broken or loose
connection, poor ground connection, or blower mo-
tor defective.

REFRIGERANT COMPONENTS ALL MODELS9s. 41
BIower Operating Normal Check for the following:Restriction or leakage in air ducts, A/C outlets not
opening.2. Do not carry cylinder in passenger compartment
of car.3. Do not subject cylinder to high temperatures.
MAINTENANCE AND ADJUSTMENTS4. Do not weld or steam clean on or near cylinder.
5. Do not fill cylinder completely.
GENERAL SERVICE INFORMATION AND SAFETY
PRECAUTIONS6. Do not discharge vapor into area where flame is
exposed or directly into engine air intake.
General InformationAll subassemblies are shipped sealed and dehy-
drated. They are to remain sealed until just prior to
making connections, and should be at room tempera-
ture before uncapping. This prevents condensation of
moisture from air that enters the system.
All precautions should be taken to prevent damage
to fittings or connections. Even minute damage to a
connection could cause it to leak. Any fittings with
grease or dirt on them should be wiped clean with a
cloth dipped in alcohol.
Do not clean fitting or hoses with solvents because
they are contaminants. If dirt, grease or moisture
gets inside the pipes or hoses and cannot be removed,the pipe or hose is to be replaced. Use a small amount
of clean refrigeration oil on all tube and hose con-
necting joints, and lubricate the
“0” ring gasket with
this oil before assembling the joint. The oil will help
in effectitig a leak-proofjoint and assist the
“0” ring
to slip into the proper location without being cut or
damaged. Always use new
“0” rings.
When tightening joints, use a second wrench to hold
the stationary part of the connection to prevent
twisting and to prevent hose kinking. Kinked hoses
are apt to transmit noise and vibration. Tighten all
connections in accordance with recommended
torques (see Division VI, Specifications).7. Do not expose eyes to liquid
- WEAR SAFETY
GOGGLES whenever discharging, charging or leak
testing system.
CHARGING AND DISCHARGING SYSTEMRemoval of any part in the refrigerant circuit will
require discharging of the entire system.
Discharging the System1. Remove caps from gauge fittings on the compres-
sor adapter fitting on the compressor.
2. With both valves on manifold gauge set (J-5725-
04) closed (clockwise), attach manifold to the com-
pressor adapter fitting on the compressor, using
J-5420 valve adapter at suction gauge fitting and
J-9459 valve adapter at discharge gauge fitting. See
Figure
9B-41.3. Fully open high pressure valve on manifold gauge
set to allow escape of refrigerant from system
through the manifold gauge set and out the center
fitting and hose. (Place end of hose in clean container
to collect oil loss due to rapid discharge of system).
4. When hissing ceases, indicating all refrigerant
has escaped, close high pressure valve on manifold
gauge set by turning valve clockwise.
Do not connect receiver-dehydrator assembly until
all other connections have been made. This is neces-
sary to itisure maximum moisture removal from sys-
tem.It is important that air conditioning hoses do not rest
on or contact body sheet metal except where neces-
sary. Because of the high frequency at which the
compressor operates, the passenger compartment is
susceptible to transfer of noise.
Evacuating the SystemWhen the refrigeration system is depressurized and
opened for service, some air will enter the lines, re-
gardless of how quickly openings are capped. In
or-der to remove this air and as much as possible of the
moisture it contains, the complete system must be
evacuated. Evacuating is merely the process of
removing all air from the system, thereby creating a
vacuum in the system.
Safety PiecautionsThe following safety precautions should always be
followed~,when servicing refrigerant charged compo-nents:Under no circumstances should alcohol be used in
the system in an attempt to remove moisture,
regard-less of the successful use of alcohol in other refrigera-
tion systems.
Preparations for Evacuating Complete System
1. Do not leave Refrigerant-12 cylinder uncapped.
1. Check the low pressure gauge for proper calibra-