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 180 of 524
TB 9-2320-279-13-1
0015-12
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).
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.
POSSIBLE PROBLEMS
Restricted AC hose.
AC compressor faulty.
Temperature control switch faulty.
Moisture in AC refrigerant system.
Air or other contaminant in AC refrigerant
system.
6.
Does AC test set recovery/
recycling manifold gage
indicate low system high-side
pressure?
Go to Step 8 of this
fault.
NO
YES
Read WARNING on
page 0015-13.
WARNING
TEST OPTIONS
Pressure test.
AC test set manifold gages.
REASON FOR QUESTION
To isolate system fault.
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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.
Temperature control switch OK.
No air or other contaminant in AC refrigerant
system.
POSSIBLE PROBLEMS
Restricted AC hose.
AC compressor faulty.
7.
Are AC hoses from low-side
AC service valve to high-side
AC service valve free from
frost and cool spots?
NO
YES
Read WARNING on
page 0015-13.
WARNING
TEST OPTIONS
Visual inspection.
REASON FOR QUESTION
If frost or cool spots are
forming on AC hoses,
AC hoses are restricting
R-134a refrigerant flow.
If not, AC compressor is
faulty.
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.
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
(WP 0050).
Verify repair, go to Step 22
of this fault.
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