TB-9-2320-279-13-1
TECHNICAL BULLETIN; AIR CONDITIONING SYSTEM
OPERATOR’S, UNIT AND DIRECT SUPPORT MAINTENANCE MANUAL, INSTALLATION INSTRUCTIONS, AND REPAIR PARTS AND SPECIAL TOOLS LISTS
DECEMBER 2005
TB-9-2320-279-13-1 - Page 190 of 524
TB 9-2320-279-13-1
0015-22
AC DOES NOT COOL OR COOLS INADEQUATELY - Continued
DRAFT
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KNOWN INFO
Power to AC system OK.
AC heater/evaporator blower OK.
AC control circuits OK (except for
temperature control and low pressure
switches).
No moisture in AC refrigerant system.
AC low pressure switch OK.
No AC condenser dryer desiccant
contaminant in AC refrigerant system.
No AC refrigerant oil contaminant in AC
refrigerant system.
AC system charge is not low.
No AC system leaks.
Temperature control switch OK.
No air or other contaminant in AC refrigerant
system.
AC condenser dryer OK.
AC evaporator core OK.
AC condenser core OK.
AC system not overcharged.
POSSIBLE PROBLEMS
Restricted AC hose.
AC compressor faulty.
AC expansion valve faulty.
14.
Is AC hose from low-side AC
service valve to AC
compressor free from frost
and cool spots?
Recover R-134a
refrigerant
(WP 0050).
Replace
restricted AC hose
(WP 0040) and AC
condenser dryer
(WP 0025).
Evacuate and charge
system (WP 0050).
Verify repair, go to
Step 22 of this fault.
NO
YES
Read WARNING on
page 0015-23.
WARNING
TEST OPTIONS
Visual inspection.
REASON FOR QUESTION
If frost or cool spots are
forming on AC hose, AC
hose is restricting R-134a
refrigerant flow.
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KNOWN INFO
Power to AC system OK.
AC heater/evaporator blower OK.
AC control circuits OK (except for
temperature control and low pressure
switches).
No moisture in AC refrigerant system.
AC low pressure switch OK.
No AC condenser dryer desiccant
contaminant in AC refrigerant system.
No AC refrigerant oil contaminant in AC
refrigerant system.
AC system charge is not low.
No AC system leaks.
AC condenser core OK.
AC expansion valve OK.
AC system not overcharged.
AC condenser dryer OK.
AC evaporator core OK.
No restricted AC hoses.
AC compressor OK.
Temperature control switch OK.
POSSIBLE PROBLEMS
Air or other contaminant in AC refrigerant
system.
15.
Does system high-side
pressure vary with engine
RPM?
NO
YES
Read WARNING on
page 0015-23.
WARNING
TEST OPTIONS
Pressure test.
AC test set manifold gage.
REASON FOR QUESTION
If system high pressure
varies with engine RPM,
AC expansion valve is
faulty.
If not, AC
compressor is faulty.
Recover R-134a refrigerant
(WP 0050).
Flush system
(WP 0050).
Then replace AC
compressor (WP 0023) and AC
condenser dryer (WP 0025).
Evacuate and charge system with
new R-134a refrigerant
(WP 0050).
Verify repair, go to
Step 22 of this fault.
Recover R-134a refrigerant (WP 0050).
Replace AC expansion valve (WP 0030)
and AC condenser dryer (WP 0025).
Evacuate and charge system with new
R-134a refrigerant (WP 0050).
Verify
repair, go to Step 22 of this fault.
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