1991 MITSUBISHI ECLIPSE heater

HEATERS AND AIR CONDITIONING - Service Adjustment Procedures 24-I 1
SERVICE ADJUSTMENT PROCEDURES
MANIFOLD GAUGE SET INSTALLATION
Suction
gauge
N24FDAF
Discharge
hose
7 Discharge
Port20A0460Manifold Gauge Valves-should be closed when connecting the manifold gauge set to the service port of
the compressor and the discharge hose. 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 openedto provide a passage between the discharge pressure gauge and the center manifold outlet.
Detailed instructions for proper use of the gauge set manifold are contained in the text covering each test andservice operation employing these gauges.
Suction Gauge-the left side of the manifold set is calibrated to register 0 to
100 kPa (0 to 15 psi) and 0 to
1,000
kPa (0 to 145 psi). This gauge is connected to the suction port of the compressor.
Discharged Gauge-the right of the manifold set is calibrated to register 0 to
2,100 kPa (0 to 305 psi). For all
tests this gauge is connected to the discharge port of the system.
Center Manifold Outlet-provides the necessary connection for a long service hose used when discharging
the system, using a vacuum pump to “pull a vacuum”before charging the system, and for connecting the
supply of refrigerant when charging the system.
TEST PROCEDURESN24FEAS
RECEIVER DRIERTo Test the Receiver Drier
(1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the receiver
drier is restricted.
Replace the receiver drier.
SIGHT GLASS REFRIGERANT LEVEL TEST
The sight glass is a refrigerant level indicator. To check the
refrigerant level, clean the sight glass and start the vehicle
engine. Push the air conditioner button to operate the
compressor, place the blower switch to high and move the
temperature control lever to max cool. After operating for a fewminutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged,
the compressor discharge line is warm and the compressorinlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged
and there is no significant temperature difference between
compressor inlet and discharge lines: the system has lost
some refrigerant.

24-12 HEATERS AND AIR CONDITIONING - Service Adjustment Procedures
------__--210 2352,100 Pressure
(30) (33)(299) 2&
kPa(psi)2OPOO14(3) If the sight glass is clear and the magnetic clutch is
disengaged; the clutch is faulty or, the system is out of
refrigerant. Perform low pressure switch test to determine
condition. Check low pressure switch, and clutch coil for
electrical continuity.
(4) If the sight glass shows foam or bubbles, the system could
be low on charge. Occasional foam or bubbles are normal
when the ambient temperature is above
43°C (110°F) or
below
21°C (70°F).Adjust the engine speed to 1,500 rpm. Block the air-flow
thru the condenser to increase the compressor discharge
pressure to 1,422 to 1,520
kPa (206 to 220 psi). If sight
glass still shows bubbles or foam, system charge level is
low.The refrigerant system will not be low on charge unless
there is a leak. Find and repair the leak. If the leak can be
repaired without discharging the system an oil level check
is not necessary. Use the procedure for correcting low
refrigerant level found in the Refrigerant System Service
Procedure Section.DUAL PRESSURE SWITCH
The dual-pressure switch is a combination of the low-pressureswitch (for checking the quantity of refrigerant) and the,
high-pressure switch (for prevention of overheating); it is
installed on the tube, and, when the pressure becomes
approximately 210 kPa (30 psi) or lower, the compressor stops,thus preventing the compressor from being damaged by heat.
When the pressure reaches 2,700
kPa (384 psi) or higher, the
compressor stops, thus preventing overheating. There is
generally no necessity for inspection; if, however, an unusual
condition, such as non-operation of the compressor is encoun-tered, check by following the procedures below.
(1) Check for continuity of the dual-pressure switch.
NOTEIf the air temperature drops to
0°C (32°F) or lower during
cold weather, the air conditioner will not operate (no
continuity).(2) If there is an insufficient amount of refrigerant, check the
refrigerant amount by looking through the sight glass of thereceiver; supply refrigerant if necessary.
(Refer to P.24-21.)

HEATERS AND AIR CONDITIONING - Service Adjustment Procedures 249*I3
--Air-therm0
sensor
Air inlet
sensor
E>aporator(3)
Set the gauge manifold in place and check whether or not
the pressure at the high-pressure side has become the
dual-pressure switch activation pressure.
(4) Replace the switch if, under ordinary conditions, there is no
continuity.Caution
The condition can be considered to be satisfactory if
there is continuity.
Never increase the pressure in a deliberate attempt to
obtain an abnormally high temperature, because to do
so risks blowing the compressor relief valve.AIR-THERM0 SENSOR AND AIR-INLET SENSOR
If frost forms on the surfaces of the evaporator fins, the cause
might be a malfunction of
air-therm0 sensor.
The temperature of the air-flowing from the evaporator’s outlet
is sensed by the thermistor, and the signals conveying this dataare input to the air conditioner control unit, thus switching the
compressor’s clutch ON or OFF.
This functions when the evaporator’s air-flow is low, or the
evaporator’s fins are clogged by dust, etc., or when the amountof refrigerant is insufficient.
These sensors detect the temperature within the passenger
compartment and the temperature at the cooling unit inlet,
thus causing changes of the resistance value, and this data is
provided to the air conditioner control unit as input.
How to Test the Therm0 Sensor and Air-Inlet Sensor
(1) Disconnect the sensor’s connector at the evaporator case,
and by using an ohmmeter, measure the resistance. The
resistance is normal if it is within the range shown in the
figure at the left; if the resistance is not normal, replace.
(2) If the sensor is normal, there is a malfunction of the air
conditioner control unit, and it should be replaced.
Standard value:
Passenger compartment temperature sensor resist-
ance value:
0°C (32°F)4,852+243 (S-2)
15°C (59°F)2,341+234 (S-2)
25°C (77°F)1,500+150 (52)
ENGINE COOLANT TEMPERATURE SWITCH
<2.0L DOHC Engine>
The engine coolant temperature switch is connected in series
with the compressor magnetic clutch power relay.
It disengages the compressor when the temperature of
engine coolant rises above
115°C (239°F).This is designed to prevent engine overheating when cooling
air is not sufficient for the condenser and radiator. If the enginecoolant temperature switch operates to disengage the com-
pressor, check for the condenser and radiator surface condi-
tions, belt tension and engine coolant level and correct, if
necessary.

24-14 HEATERS AND AIR CONDITIONING - Service Adjustment Procedures
-Discharge
w-w
SuctiongaugeDischalgauge
2OUO306
SuctiongaugeDischargegauge
2OUO307--
MAGNETIC CLUTCH(I) Disconnect the wiring to the magnetic clutch.
(2) Connect battery (+) voltage directly to the wiring for the
magnetic clutch.
,”(3) If the magnetic clutch is normal, there will be a “click”. If
the pulley and armature do not make contact (“click”),
there is a malfunction.
Using an ohmmeter, measure the resistance of the clutch
coil between the clutch lead wire and ground.
Standard resistance: 3.4-3.8
Q at 20°C (88°F)If resistance is not as specified, replace the coil.
COMPRESSOR(1) Install the manifold gauge set, and run the air conditioner.
(2) If a pressure of approx. 490 kPa (71 psi) is indicated on the
suction gauge side and a pressure of approx. 883
kPa (128
psi) is indicated on the discharge gauge side, the compres-
,“ssor has abnormal compression.
-IReplace the compressor.
(3) If a pressure of 294 to 392 kPa (43 to 57 psi) is indicated on
the suction gauge side and a pressure of approx. 1,961
kPa(284 psi) is indicated on the discharge gauge side, it is
suspected that air is present in the air conditioning system.Discharge the system, evacuate and recharge with speci-
fied amount of refrigerant.
(4) During operation of the air conditioner, cold air may stop
flowing after the elapse of time and this state is maintainedbefore cold air flows out again. If cold air stops flowing out
with negative pressure indicated on the suction gauge sideand a pressure of 588 to 980
kPa (85 to 142 psi) indicated
on the discharge gauge side, it is suspected that water is
present in the air conditioning system.
L=I
Discharge the system. Replace receiver drier. Evacuate and-check for leaks, and recharge with specified amount of
refrigerant.

HEATERS AND AIR CONDITIONING - Service Adjustment Procedures 24-15
Liquid
line
\Liquid lineI
ILiquid lineHigh pressure
hose2010439
detector torch
Electric leakAdetector tester
2OUO338
TESTING SYSTEM FOR LEAKSNUFFADA leak is likely to occur where two components are connected
together. See the illustration for possible locations.
The Leak Detector Torch is a butane gas-burning torch used to
locate a leak in any part of the refrigeration system.Refrigerantgas drawn into the sampling or “sniffer” hose will cause the
flame to change color in proportion to the size of the leak. A
very small leak will produce a flame varying from yellowish-
green to bright green. A large leak will produce a briliant blue
flame.Caution
Do not use the lighted detector in any place where
explosive gases, dust or vapors are present. Do not
breathe the fumes that are produced by the burning of
refrigerant gas. Large concentrations of refrigerant in the
presence of a live flame become dangerously toxic.
If the flame remains bright yellow when the tester is removed
from a possible leak point, insufficient air is being drawn in
through the sampling tube, or the copper reaction wire is dirty.
(1) Assemble leak detector as shown in the illustration, and be
sure detector is seated tightly over torch gasket.
(2) Holding torch upright, screw-in butane charger (clockwise)
until punctured. (Do not use force).
(3) Screw-out butane charger (anticlockwise) about
l/4 turn.
(4) Point torch away from body-then light escaping gas with
match. Always keep torch in upright position.
(5) Adjust flame by turning cartridge in or out as required.
(6) Allow 30 seconds to heat copper reaction wire.
Caution
Never remove butane charger while torch is lighted or
in the presence of any open flame.
(7) Examine all tube connectors and other possible leak points
by moving the end of the sampling hose from point to
point. Always keep torch in upright position. Since
R-12 is
heavier than air, it is good practice to place the open end of
sampling hose directly below point being tested. Be careful
not to pinch sampling tube since this will shut off air supplyto flame and cause a color change.
(8) Watch for a change in the color of the flame.
Small leaks will produce a green color and large leaks a
bright blue color. If leaks are observed at tube fittings,
tighten the connection, using the proper flare wrenches,
and retest.
NOTE
A leakage of refrigerant can be detected by an electric leakdetector that emits a warning sound.

24-16 HEATERS AND AIR CONDITIONING - Service Adjustment Procedures
PERFORMANCE TESTN24FWAFa(1) Park the tested vehicle at the area which is not exposed to
the direct sunlight.
(2) Connect a tachometer and manifold gauge set.
(3) Set the controls of the air conditioner as follows:
Air conditioning switch: A/C-ON position
Mode selection lever: Face position
Temperature control lever: Max. cooling position
Air selection lever: Recirculation position
Blower switch: HI (Fast) position
(4) Start engine and adjust rpm to 1,000 with air conditioner
clutch engaged.
(5) Engine should be warmed up with doors, windows close
and hood open.
(6)Insert a thermometer, to a depth of 20-30 mm (8-I .2 in.),into the left center air conditioner outlet, and operate the
engine for
20 minutes.
(7) Note the discharge air temperature.
NOTEIf the clutch cycles, take the reading before the clutch
disengages.
PERFORMANCE TEMPERATURE CHART
Garage ambienttemperature “C (“F)21 (70)26.7 (80)32.2(90)37.8(100)43.3(110)
Discharge air2.0-8.02.0-8.02.0-8.04.0-11.06.0-14.0temperature
“C (“F)(35.6-46.4)(35.6-46.4)(35.6-46.4)(39.2-51.8)(42.8-57.2)
Compressordischarge pressure900-1.3001.000-1.400l,lOO-1,5001,300-1,7001,500-1,900
kPa (psi)(128-186)(142-199)(156-212)(186-242)(212-270)
’Compressor suction50-15080-180100-200130-230150-250
pressurekPa (psi)(7.1-21.3)(11.4-25.6)(14.2-28.4)(18.5-32.7)(21.3-35.6)

HEATERS AND AIR CONDITIONING - Service Adjustment Procedures 24-Q
ilectric leakletector tester
2OUO333
40°C(I 04°F)20A0463
REFRIGERANT LEAK REPAIR PROCEDURE N24FtiAOLost Charge
If the system has lost all charge due to a leak:
(1) Evacuate the system. (See procedure.)
(2) Charge the system with approximately one pound of
refrigerant.(3) Check for leaks.
(4) Discharge the system.
(5) Repair leaks.
(6) Replace receiver drier.
Caution
Replacement filter-drier units must be sealed while in
storage. The drier used in these units will saturate
water quickly upon exposure to the atmosphere. When
installing a drier, have all tools and supplies ready for
quick reassembly to avoid keeping the system open
any longer than necessary.
(7) Evacuate and charge the system.
Low Charge
If the system has not lost all of its refrigerant charge; locate
and repair all leaks. If it is necessary to increase the system
pressure to find the leak (because of an especially low charge)add of refrigerant. If it is possible to repair the leak without
discharging the refrigerant system, use the procedure for
correcting low refrigerant level.
CORRECTING LOW REFRIGERANT LEVEL
Since the refrigeration system is completely sealed, refrigerant
level will not be low unless there is a leak in the system. Beforeadding refrigerant when the cause of low level is not known,
the system should be tested for leaks. Assuming that leaks
have been corrected without discharging the system, proceed
with partial charge.
Install and connect manifold gauge set.
(1) Close both gauge set manifold valves.
(2) Connect the suction gauge test hose to the suction port of
the compressor. Connect the discharge gauge test hose tothe discharge port.
(3) Connect one end of long test hose to center manifold
outlet, other end to refrigerant dispensing manifold.
(4) Close two dispensing manifold valves and open remaining
dispensing manifold valve. Remove protective cap from
opened valve.

24-18 HEATERS AND AIR CONDITIONING - Service Adjustment Procedures
(5) Screw a can of R-12 to the opened manifold valve. Be sure
gasket is in place and in good condition. Tighten refrigerantcan and manifold locking nut to insure a good seal. Do not
overtighten 8 to
11 Nm (6 to 8 ft.lbs.) is sufficient if gasket
is in good condition.
(6) Turn manifold valve (above the refrigerant can) completely
clockwise to puncture the can. This closes the valve and
seals the refrigerant in the can.
Caution
Never heat small cans of refrigerant over
40°C (104°F)as they may explode.
(7) Place the refrigerant in a large pan of water heated to 52°C
(104°F). Place pan of water containing the refrigerant can
on an accurate scale so the amount of refrigerant added
can be weighed. Open the refrigerant manifold valve.
(8) Purge all air from test hoses. Air in the system will be
trapped in the condenser causing abnormally high dis-
charge pressures and interfering with condensing of the
refrigerant.(9) Slightly loosen both test hoses at the gauge set manifold.
Tighten the hoses as soon as the air is purged.
(10)Slightly loosen charging hose connection at gauge set
manifold. This will purge air from the charging hose.
Tighten connection as soon as air is purged.
(I l)With vehicle windows open and hood up, operate engine at1,500 rpm and jump the low pressure switch terminals
located on the receiver drier so the clutch will remain
engaged.
(12)Place air conditioner control on air conditioner and place theblower switch on high.
(13)lf necessary, block the condenser to maintain a discharge
pressure of 1,422 to 1,520
kPa (206 to 220 psi). System
must be charged through the evaporator suction service
ports as follows:
(a) Slowly open the suction service gauge valve.
Meter flow of refrigerant by adjusting, the suciton
service gauge valve so that pressure registered at the
suction service gauge does not exceed 345 kPa (50 psi).Keep refrigerant container upright.
(b) Add refrigerant gas until there is no foam visible at the
sight glass.
Add an additional
170 g (6 oz.)
(c) Close the suction gauge valve.
CautionToo much refrigerant in the system can cause
abnormally high discharge pressures. Care must beused so that the exact recommended amount or
refrigerant is added after foam clears in the sight
glass.(d) Close dispensing manifold valve. Remove test hoses
and adapters from the service ports of compressor,
install protective caps at service ports and reconnect
wiring.(e) Check system performance.
(P.24- 16.)
e
. i”
A
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