TM 5-3805-290-23-1
TROUBLESHOOTING WITHOUT A DIAGNOSTIC CODE - CONTINUED
0008 00
Table 8. Air Conditioning System Troubleshooting.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
N OT E
When ambient temperature is above 70F (21C), a low pressure gage reading of 10 to 20 psi (70 to 138
kPa) is a normal operating pressure for AC system. Also, when ambient temperature is above 70F
(21C), a high pressure gage reading of 120 to 190 psi (820 to 1,300 kPa) is a normal operating pressure
for AC system. In very hot weather, low pressure readings and high pressure readings will be at high
end of normal operating range. In cooler weather, low pressure reading will be in middle to low end of
normal operating range, while high pressure reading will be low. For correct gage reading in relation
to ambient temperature conditions, refer to table below. This table is only for reference.
All pressures are given as a guide only. Weight is only absolute means of determining proper refriger-
ant charge. Improper refrigerant charge will cause premature failure of compressor.
Unless directed otherwise, all troubleshooting listed requires that pressure gages be connected (WP
0191 00) to compare system pressures with table below.
Ambient temperature is above 70F (21C) in all malfunctions.
Arc Suppressor Test is available in WP 0018 00.
PRESSURE RANGE
High Pressure Test Fitting (Pressure May
Ambient Air Temperature
Low Pressure Test Fitting (Pressure Before
Be Slightly Higher in Very Humid
Clutch Disengagement)
Conditions and Lower in Very Dry
Conditions)
70F (21C)
10 to 20 psi (70 to 138 kPa)
120 to 190 psi (820 to 1,300 kPa)
80F (27C)
10 to 25 psi (70 to 173 kPa)
140 to 210 psi (950 to 1,450 kPa)
90F (32C)
15 to 30 psi (105 to 210 kPa)
170 to 240 psi (1,175 to 1,650 kPa)
100F (38C)
190 to 270 psi (1,300 to 1,850 kPa)
15 to 30 psi (105 to 210 kPa)
110F (43C)
210 to 300 psi (1,450 to 2,075 kPa)
15 to 30 psi (105 to 210 kPa)
N OT E
1.
Temperature of Air Flow is
Partially Cool.
Leaks in refrigerant circuit will cause system to be low on refrigerant.
1. Check low and high pressure gage
1. If both readings are below normal, go
to Test 2.
during AC operation (WP 0018 00).
2. If low pressure gage reading is normal
but high pressure gage reading bounces
or reading is unsteady, go Test 3.
3. If low pressure gage reading is below
normal but high pressure gage reading
is normal to below normal range, go to
Test 4.
4. If low pressure gage reading does not
change and pressure gage reading is at
high end of normal range, go to Test 7.
5. If low pressure gage reading is above
normal, high pressure gage reading is
below normal, and system is fully
charged, go to Test 8.
