set clock OPEL 1900 1973 User Guide

REFRIGERANT COMPONENTS ALL MODELS9B- 43
4. Start the vacuum pump and slowly open low and
high pressure sides of manifold gauge set to avoid
forcing oil out of refrigeration system and pump,
Pressure is now being reduced on both sides of the
refrigeration system. If oil is blown from the vacuum
pump, it should be refilled to the proper level.
5. Observe low pressure gauge and operate vacuum
pump until gauge shows 28-29 inches vacuum. In all
evacuating procedures, specifications of 28-29 inchesof vacuum is used. This evacuation can only be at-
tained at or near sea level.
For each 1000 feet above sea level where this operat-ion is being-performed, the specification should be
lowered by one inch of mercury vacuum. At 5000
feet elevation, only 23 inches to 24 inches of vacuum
can normally be obtained.
If vacuum cannot be pulled to the minimum specifi-
cation for the respective altitude, it indicates a leak
in the system or gauge connections or a defective
vacuum pump. In this case, it will be necessary to
check for leaks as described under “Leak Testing
Refrigerant System”.
When specified vacuum level (28-29 inches at sea
level) is obtained, continue to run vacuum pump for
ten (10) ‘additional minutes. During these ten (10)
minutes:
A. Prepare for charging the system. If using a charg-
ing station, till charging cylinder. If using manifold
gauge set, make all preparations for charging system
as described under “Disposable Can Method” or
“Refrigerant Drum Method”.
B. Measure oil loss collected as a result of rapid
discharge.
C. Uncap compressor oil injector (J-24095) and open
valve. Flush J-24095 with refrigerant, close valve and
insert pick-up tube into graduated container of clean
refrigerant oil.
D. Con&ct J-24095 to suction fitting at the compres-
sor adapter fitting. When valve on J-24095 is opened,
the vacuum applied to the discharge side of the sys-
tem will suck oil into system from container. There-
fore,
close observation of oil level in the container is
necessary.E. Note level of oil in container. Open valve on
J-24095
u+il oil level in container is reduced by an
amount equal to that lost during discharge of system,
then shut valve. Take care not to add more oil than
was lost. ,,
F. Disconnect J-24095 and attach pick-up tube fit-
ting to schraeder fitting to cap tool. See Figure 9B-
42.J-24095
-98.32
Figure 98.42 Oil Injector J-24095
6. Turn hand shut-off valves at low and high pressure
gauges of gauge set to full clockwise position with
vacuum pump operating, then stop pump. Carefully
check low pressure gauge approximately for two (2)
minutes to see that vacuum remains constant. If
vacuum reduces, it indicates a leak in the system or
gauge connections.
Charging the SystemThe system should be charged only after being eva-cuated as outlined in “Evacuating the System”.
Refrigerant orurn Method
1. Connect center flexible line of gauge set to refriger-ant drum.
2. Place refrigerant drum in a pail of water which has
been heated to a maximum of 125 degrees F.
WARNING: Do not allow temperature of water to ex-
ceed I25
degrees E High temperature will cause
safety plugs in the refrigerant drum. It may not be
necessarv to use hot water if a /arae drum is used(over
ap)roximateIy 100 lbs.).-I3. Place refrigerant drum (in pail of water) on scales
(bathroom or commercial, perferably commercial).

9B-44 1973 OPEL SERVICE MANUAL
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 2
Ibs.Opel 1900
- Manta and 2 l/4 lbs. GT, of refrigerant
have been transferred from refrigerant drum to sys-
tem.If full charge cannot be obtained, close both valves
on gauge set, start engine, and set temperature con-
trol knob to full cold position with blower in Max Hi.
Open low pressure valve on gauge set slowly and
leave open until full charge is added.
WARNING: Observe high pressure gauge while charg-
ing with compressor running. Shut
offengine ifpres-
sure exceeds 250 psi. A large fan placed in front
ol
the car wi// help reduce excessively high head pres-6. Close both valves on gauge set (high pressure valve
will already be closed if charging was completed by
running compressor) and close valve on refrigerant
drum.
If the engine was used to complete the 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, blower speed in Max Hi.
After ten minutes of operation, observe appearance
of refrigerant in receiver-dehydrator. If bubbles are
observed, open low pressure gauge valve and valve
on refrigerant drum to allow more refrigerant to en-
ter system. Close valve when receiver-dehydrator
clears
up.If an air inlet temperature is below 70 degrees F.
when this check is made, bubbles may appear, even
though the proper amount of refrigerant is in the
system. Air inlet temperature must be 70 degrees F.
or above to make an accurate check.
8. When refrigerant has been installed, continue to
operate system and test for proper operation as ou-
tlined under “Operational Test”.
9. When satisfied that air conditioning system is op-
erating properly, stop engine, remove gauge set and
replace protective caps on compressor fittings.10. Using leak detector, check complete system for
leaks.Disposable Can Method
After having
depress&ed, repaired (if necessary)
and evacuated the refrigerant system, the system
may be charged as follows using refrigerant in dis-
posable cans:
1. Obtain three (3) 1
lb. cans or one 12 lb. can of
refrigerant.
2. If using 1 lb. cans, mount two (2) cans in J-6272-
02 (Multi-opener) or attach J-6271 (single-can
opener valve) on one can. If using the 12
lb. disposa-
ble can, attach J-23390 (disposable can control valve)
on can.WARNING: Make sure outlet valve on opener is
closed (clockwise) before installing opener.A. If the J-6272-02 multi-opener is used, raise lock-
ing lever, position three (3) cans of refrigerant and
force locking lever down to secure cans and at same
time puncture top of can to make it ready for charg-
ing.
B. If the J-6271 valve is used, back off the valve from
the can top retainer, slip the valve onto the can and
turn the valve into retainer until tight. DO NOT
open outlet valve during this operation, as turning
the valve into the retainer punctures top of can to
make it ready for charging.
3. Connect center flexible line of gauge set to fitting
on a can opener valve. If the line at center gauge
fitting has not been purged of air, loosen line at
center fitting on gauge set and “crack” valve at can
opener (for a second or two) to force air from the
line. Retighten line at center fitting.
4. Open valve at refrigerant source and at low and
high pressure valves on manifold gauge set. Leave
valve open at refrigerant source until all refrigerant
(when using 1 lb. can) has ‘entered the refrigeration
system or system is fully charged. Close valve on can.
A. If the system is charged using
1 lb. cans and the
J- 627 1 valve, disconnect valve from can. Leave valve
closed to flexible line to the center fitting of the
manifold gauge set. Install valve on a new and full
disposable can of refrigerant.

REFRIGERANT COMPONENTS ALL MODELS9t3- 45
B. If system is charged using J-6272-02, close the
valve of opener after all cans are empty. Release the locking lever and discard the three (3) empty cans.
If this tool will be used to complete the charge with
additional cans to provide the required refrigerant
charge, leave the empty cans in position, locate one
full can and lock the lever into place. These empty
cans balance the assembly and prevent the loss of
refrigerant through the open “series” passage. Align
the pierced hole in the empty can with the punch in
the cover of the tool.
If the J-6271 valve for single cans is available, com-
plete charging as explained in 4a above.
5. Close high side valve on manifold gauge set,
WARNING: Prior to starting up engine, the high side
valve on the charging manifold must be closed due
to excessive pressure
bui/d-up which can result in
bursting of the container(s) causing serious injury. If
you are inexperienced in the use of this procedure, seek professional assistance.
6. Operate engine at 2000 RPM with temperature
control knob at full cold position and blower speed
on Max Hi. If air inlet temperature at the condenser
is below 70 degrees F. when this check is made,
bubbles may appear, even though the proper amount
of refrigerant is in the system. Air inlet temperature
must be 70 degrees F. or above to make an accurate
check.
7. When refrigerant has been installed, continue to
operate system and test for proper operation as ou-
tlined
under “Operational Test”.
8. When satisfied that the air conditioning system
is operating properly, stop engine, remove gauge set
and replace protective caps on suction and discharge
fittings.
from thegauge fitting to prevent damage-or injury to
personnel.
9. Using a leak detector, check complete system for
leaks.
Charging Station Method
INSTALLING J-8393-02
-
1. Be ceitain compressor hand shut-off valves to
gauge fittings are closed (counterclockwise).
2. Be certain all valves on charging station are
closed.
3. Connect high pressure gauge line to compressor
high pressure gauge fitting.
4. Turn high pressure hand shut-off valve one turn
clockwise, and high pressure control one turn coun-
terclockwise (open). Crack open low pressure con-
trol and allow refrigerant gas to hiss from low
pressure gauge line for three seconds, then connect
low pressure gauge line to low pressure gauge fitting
on compressor adapter fitting. (Place J-9459 adapter
on hose, then attach adapter to gauge fitting.)
FILLING CHARGING CYLINDER
1. Open Control valve on refrigerant container.
2. Open valve on bottom of charging cylinder, al-
lowing 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.
While filling the cylinder, it will be necessary to close
the bleed valve periodically to allow boiling to sub-
side so that refrigerant level in the charging cylinder
can be accurately read.
CHARGING THE SYSTEM USING J-8393-02
1. With charging station connected, as previously
described, remove low pressure gauge line at com-
pressor adapter fitting.
2. Crack open high and low pressure control valves
on station and allow refrigerant gas to purge from
system. Purge slowly enough so, that oil does not
escape from system along with refrigerant.
3. When refrigerant flow nearly stops, connect low
pressure gauge line to
compress& adapter fitting.
4. Turn on vacuum pump and open vacuum control
valve.
5. With system purged as
abovk, 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.
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
performed, the specifications should be lowered by 1
inch. For example, at 5000 feet 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 and

98-46 1973 OPEL SERVICE MANUAL
shut off vacuum pump. Open refrigerant control
valve and allow some refrigerant to enter system.
Locate and repair all leaks.
7. After evacuating for 15 minutes, add l/2 lb. of
refrigerant to system. Purge this
l/2 lb. and reevacu-
ate 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, till to proper level.
9. Close low pressure valve on charging station.
Fully open station refrigerant control valve and al-
low 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.
10. If full charge of refrigerant will not enter system,
close high pressure control and refrigerant control
valves. Start engine and run at low idle with com-
pressor 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 op-
erating. When required charge has entered system,
close refrigerant control valve and close low pressure
control.
11. System is now charged and should be perform-
ance- tested before removing gauges.
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 refrigerent to replace that
lost by leaks, check for evidence of oil loss and add
oil if necessary.
This procedure will only apply if the air inlet temper-
ature is above 70 degrees F. at the condenser.
1. Remove caps from 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.
2. Start engine, turn air conditioning temperature
control knob to full cold position, blower switch to
Max Hi. Operate for ten
(IO) minutes at 2000 RPM
to stabilize system.
3. Observe the refrigerant through the sight glasscover of receiver-dehydrator with the system operat-
ing,
IO 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 1 lb. of refrigerant as
explained under “Charging the
ISystem”.b. If bubbles are visible in the receiver-dehydrator
with the temperature control krlob in the full cold
position and the blower at MAX speed, it indicates
a partial or complete plug in a line, a shortage of
refrigerant, or both. Correct condition. Add refriger-
ant
u~ntil the sight glass clears, then add another 1 lb.
of refrigerant.
4. Attach flexible hose from center fitting of gauge
set loosely to refrigerant drum or on disposable can
valvxs. 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 ihat all air has been removed from gauge lines.
Close (clockwise) both hand shut-off valves or gauge
set.5. Partially charge system.
REFRIGERANT DRUM METHOD:
A. Place pail containing hot water that does not have
a temperature exceeding 125 degrees F. on scales,
place refrigerant drum in pa” containing water, note
weig,ht and only open low pressure valve on gauge
set.B. Start engine, turn temperature control knob to full
cold position and place blower switch in Max Hi.
Operate engine for 10 minutes at 2000 RPM to sta-
bilize system.
C. With compressor operating, slowly open valve on
refrigerant drum and allow refrigerant to flow into
system (through manifold gauge set) until liquid in-
dicator clears up and immediately shut off valve ai
gauge set or on refrigerant drum. Check weight of
refrigerant drum and pail of water. Then slowly open
valve on gauge set (or refrigerant drum) and add one
more lb. of refrigerant. Note total amount of refriger-
ant added.
DISPOSABLE CAN METHOD:
A. Make sure the outlet valve on the J-6271 valve is
fully clockwise and attach the J-6271 to a 1 lb. can
of refrigerant by backing off the valve from the top
of the retainer, slipping the valve onto the can and
turning the valve into the retainer until tight. DO
NOT accidentally open outlet valve during this oper-
ation, as turning the valve into the retainer punctures
the top of the can to make it ready for charging.
.

REFRIGERANT COMPONENTS ALL MODELS96-66Figure 98.109 Removing or Installing Shaft Seal
SEAL SEAT
-Figure 98-l 10 Removing Seal Seat O-Ring
assembly engages the flats on the shaft and is seated
in place. Disengage the tool by pressing downward
and twisting tool counterclockwise.
4. Coat ihe seal face of the new seal seat with clean
refrigeration oil. Mount the seal seat on Tool J-9393
and install it in the compressor neck, taking care not
to dislodge the seal seat
“0” ring and being sure the
seal seat makes a good seal with the “0” ring.FRONT
L’HEAD
\Figure 96-l 11 Installing Seal Seat O-Ring
5. Install the new seal seat retainer ring with its flat
side against the seal seat, using No. 21 Truarc pliers
(J-5403). Use the sleeve from
Top1 J-9393 to press in
on the seal seat retainer ring so that it snaps into its
groove. Remove seal protector
Jz22974 from the end
of the shaft.
6. Install Compressor Leak Test Fixture (J-9625)
on rear head of compressor and connect gage charg-
ing lines as shown in Figure
9B-112. Pressurize suc-
tion side of compressor with Refrigerant-12 vapor to
drum pressure. Temporarily install the shaft nut and,
with compressor horizontal and oil sump down,
ro-tate the compressor shaft in nornial direction of rota-
tion several times by hand. Leak, test the seal with a
propane torch type leak
detectot; in good condition.
Correct any leak found. Remove and discard the
shaft nut.
7. Remove any excess oil, resulting from installing
the new seal parts, from the shaft and inside the
compressor neck.8. Install the new absorbent sleeve by rolling the
material into a cylinder, overlapping the ends, and
slipping it into the compressor neck with the overlap
at the top of the compressor. Using a small screw-
driver or similar instrument, carefully spread the
sleeve so that in its final position, the ends butt
together at the top vertical centerline. Install the new
sleeve retainer so that its flange face will be against
the front end of the sleeve. Using the sleeve from
Tool J-9393, press and tap with a mallet, setting the
retainer and sleeve into place, until the outer edge of

System controls are the AIR knob controlling the
three speed blower motor switch and the TEMP
knob which controls the setting of the thermostatic
switch. When operating this system, the heater must
be off for maximum cooling.DIAGNOSIS
TROUBLE DIAGNOSIS GUIDE
Air Knob
Insufficient CoolingTurning the AIR knob clockwise operates the three-
speed blower motor.CHECK AIR FLOW9B-90 1973 OPEL SERVICE MANUAL
AIR CONDITIONER SYSTEM
OPEL 1900
- MANTA
CONTENTS
Subject
DESCRIPTION AND OPERATION:
General Description of System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...”Operation of Controls
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .DIAGNOSIS:
DiagnosisGuide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..“................... . . . . . . . . .MAINTENANCE AND ADJUSTMENT:
Adjustment of Thermostatic Switch
. . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Removal81InstallationBlowerSwitch. . . . . . . . . . . . . . . . . . . . . .Page No.
9B-90
9B-90
9B-90
9B-91
98-92Removal
& Installation Temperature Control Switch
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Removal
& Installation Resistor Assembly. . . . . . . . . . . . . .Removal
& Installation Blower Motor Assembly . .
SPECIFICATIONS:
Specifications
.,...,,.,,..~.,.,..,,......,.,....,.,........,......,........ ,, . . . . . . .
98-92
98-92
98-92
98-96
DESCRIPTION AND OPERATION
GENERAL DESCRIPTION OF SYSTEMThe air conditioner is intended to give maximum
cooling comfort within the vehicle. To do this, care-
ful attention must be given to the following Sections.
The system operates on recirculated air only and is
entirely independent of the vehicle heater.
Temp KnobThis knob may be regulated to control the degree of
cooling desired. Fully clockwise provides maximum
cooling; however, turning the knob to the center de-
tent position provides adequate cooling for highway
operation.
When maximum cooling is required, outside air
should not be admitted to the car.
Recirculated inside air is drawn into the unit, passed
through the evaporator core and into the car through
the adjustable outlets in the evaporator case.
Operation of ControlsWhen the unit is set for maximum cooling and the
vehicle is being driven continuously at highway
speeds or at elevations of
4,OOC!ft. or more, there is
a possibility of the formation of ice on the evaporator
core fins.

AIR CONDITIONER SYSTEM -OPEL 1900 - MANTA9B- 91FAN DOES NOT RUN Correct electrical fault.
FAN RUNS
- Check air velocity.
NOT OK Clean evaporator inlets.
Clean evaporator core.
Clean evaporator outlets.
OK Check refrigeration (refer to Refrigeration
Diagnosis Guide).
MAINTENANCE AND ADJUSTMENTS
ADJUSTMENT OF THERMOSTATIC SWITCHThe system makes use of a thermostatic switch with
a self-supporting air sensing capillary. This capillary
controls the switch by sensing the temperature of the
air leaving the evaporator fins.
Checking for Proper Operation
I. Install the gauge set and set up the vehicle as
described under FUNCTIONAL TESTING SYS-
TEM iti Refrigerant Components Section.
2. Movement of the temperature control knob
should result in a definite change in suction pressure
and cycling of the compressor clutch.
3. If compressor continues to operate regardless of
the knob adjustment, it indicates that the switch
points are fused, which will lead to evaporator
freeze- up. The switch should be replaced.
Adjusting Switch
If, after ihe foregoing checks, the switch seems to be
operating correctly, adjust for proper setting if neces-
sary, as
~follows:1. Set up car as described in FUNCTIONAL
TESTING SYSTEM in Refrigerant Components
Section.2. The suction side of the system, read on the low
pressure gauge, should pull down to the pressure
shown in the chart in SPECIFICATIONS in Refrig-
erant Components Section.
3. Remove the face plate retaining screws and
remove face plate assembly noting the position of the
air sensipg capillary so that it can be reinstalled in
the same location as when removed. See Figure 98.170. ,:Figure
98.170 Location of Air Sensing Capillary
4. Remove the thermostatic switch retaining screws
and remove switch. Remove the non-metal end plate
from the switch to gain access tq the switch adjusting
screw. Check the screw for stripped or otherwise
damaged threads.
5. If the low side pressure
was less than the pre-
scribed pressure at the end of each cooling cycle, turn
the adjusting screw a partial turn clockwise. See Fig-
ure
9B-171.Figure 9B-17 1 Adjusting
Thkmosfatic Switch
6. If the pressure was more than the prescribed
value, turn the adjusting screw counter-clockwise.
7. Reinstall switch end plate and install switch in
face plate. Install face plate on ,evaporator assembly
assuring that the air sensing
c&pillary has been re-
placed properly.
8. Check system performance. Fffurther adjustment
is needed, repeat steps 3 thru 7 until the correct
pressure is reached.
Do not attempt to run a performance test with the
face plate and switch removed
,from the evaporator
assembly
- inaccurate reading, will result. Always
replace the switch and face plate assemblies before
checking the system performance.

AIR CONDITIONER SYSTEM - GT96. 97
AIR CONDITIONER SYSTEM
GTCONTENTS
Subject
: DESCRIPTION AND OPERATION:
General Description of System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Operation of Controls
. . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
Diagnosis Guide
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
Adjustment of Thermostatic Switch
. . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Removal 8 Installation of Vacuum Switch.
Removal&InstallationBlowerSwitch. . . . . . . . . . . . . . . . . . . . . .Removal & Installation Temperature Control Switch
. . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . .
Removal&InstallationResistor Assembly. . . . . . . . . . . . . .Removal & Installation Blower Motor Assembly . .
SPECIFICATIONS:
Specifications
. . .
. . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page No.
9BL 97
9Bi 97
9BL 98
98: 98
9B: 99
9B; 99
9B- 99
98~10098-101
9B-104
DESCRIPTION AND OPERATIONAir Knob
GENERAL DESCRIPTION OF SYSTEMTurning the AIR knob clockwise operates the three-
speed blower motor.
The air &mditioner is intended to give maximum
cooling comfort within the vehicle. To do this, care-
ful attention must be given to the following sections.
The system operates on recirculated air only and is
entirely @dependent of the vehicle heater.Temp Knob
Recirculated inside air is drawn into the unit, passed
through the evaporator core and into the car through
the adjustable outlets in the duct assembly.This knob may be regulated to cohtrol the degree of
cooling desired. Fully clock-wise provides maximum
cooling; however, turning the kndb to the center de-
tent position provides adequate cooling for highway
operation.
CONTROLSWhen maximum cooling is reqlired, outside air
should not be admitted to the car.
System c&trols are the AIR knob controlling the
three
spe&d blower motor switch and the TEMPWhen the unit is set for maximum cooling and the
vehicle is being driven continuously at highway
knob which controls the setting of the thermostaticspeeds or at elevations of 4,000 ft. or more, there is
switch. When operating this system, the heater musta possibility of the formation of ice on the evaporator
be off for maximum cooling.core tins.