DaimlerChrysler LH New Yorker 1994, Электронное руководство по обслуживанию

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SYSTEM LEAK CHECKING
WARNING: R-134A SERVICE EQUIPMENT OR VE-
HICLE A/C SYSTEM SHOULD NOT BE PRESSURE
TESTED OR LEAK TESTED WITH COMPRESSED
AIR. SOME MIXTURES OF AIR/R-134A HAVE BEEN
SHOWN TO BE COMBUSTIBLE AT ELEVATED PRES-
SURES. THESE MIXTURES ARE POTENTIALLY DAN-
GEROUS AND MAY RESULT IN FIRE OR EXPLO-
SION CAUSING INJURY OR PROPERTY DAMAGE.
If the A/C system is not cooling properly, determine
if the refrigerant system is fully charged with R-134a.
This is accomplished by performing a system Charge
Level-Check or Fill. If while performing this test A/C
original discharge pressure is less than 207 kPa (30
p.s.i.) proceed to Empty Refrigerant System Leak
Test. If discharge pressure is greater than 207 kPa
(30 p.s.i.) proceed to low refrigerant level leak test. If
the refrigerant system is empty or low in refrigerant
charge, a leak at any line fitting or component seal is
likely. A review of the fittings, lines and components
for oily residue is a indication of the leak location. To
detect a leak in the refrigerant system, perform one of
the following procedures as indicated by the symp-
toms.
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134A SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
EMPTY REFRIGERANT SYSTEM LEAK TEST
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible (approx. 28 in Hg.). Deter-
mine if the system holds a vacuum for 15 minutes. If
vacuum is held, a leak is probably not present. If
system will not maintain vacuum level, proceed with
this procedure.
(2) Prepare a .284 Kg. (10 oz.) refrigerant charge to
be injected into the system.
(3) Connect and dispense .284 Kg. (10 ozs.) of re-
frigerant into the evacuated refrigerant system.
(4) Proceed to step two of Low Refrigerant Level
Leak Test.
LOW REFRIGERANT LEVEL LEAK TEST
(1) Determine if there is any (R-134a) refrigerant
in the system. Use the DRB scan tool partial charge
test or pressure gauge liquid line temperature partial
charge check. See system charge level check or fill for
procedure.
(2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks.
(3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes with the system set
to the following:
•
Transaxle in Park
•
Engine Idling at 700 rpm
•
A/C Controls Set in 100 percent outside air
•
Full Cool
•
High Blower
•
A/C in the ‘‘ON’’ position
•
Vehicle Windows Open.
CAUTION: A leak detector designed for R-12 refrig-
erant will not detect leaks in a R-134a refrigerant
system.
(4) Shut off the vehicle and wait 2 to 7 minutes.
Then use an Electronic Leak Detector that is de-
signed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the recirculating air door opening
or a heat duct.
(5) If a thorough leak check has been completed
without indication of a leak, proceed to ‘‘System
Charge Level-Check or Fill’’.
SYSTEM CHARGE LEVEL—CHECK OR FILL
The procedure below should be used to check and/or
fill the refrigerant charge in the air conditioning sys-
tem.
The air conditioning system in this vehicle
holds 0.794 Kg. (28 oz. or 1.75 lbs.) of R-134a
refrigerant.
This procedure can be performed two different
ways:
•
With a DRB scan tool and a thermocouple. Use the
DRB scan tool diagnostic topic: Partial Charge Test.
•
Using a manifold gauge set, a thermocouple and
the Charge Determination Graph. It is recommended
to use the gages or reclaim/recycle equipment.
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134A SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
24 - 4 HEATING AND AIR CONDITIONING