caused damage to the compressor due to low
refrigerant or oil levels.
Compressors cause refrigerant to flow through the
system by creating a pressure differential, high and
low pressures. If the compressor can be forced to
produce a high pressure in excess of 350 psi (2415
kPa) it is a good compressor.
IMPORTANT: The compressor pumping test
must be performed with the refrigerant system
charged to the factory specifications, and
functioning properly. This test should only be run
for a short time period. Shut the system down
immediately once 350 psi (2415 kPa) is achie-
ved.
1.
Confirm the system is charged per the OEM re-
quirement before proceeding.
2.
Disable the engine cooling fan. The condenser
can also be blocked with sheet of cardboard.
The purpose is to limit heat removal from the
system and build compressor discharge pres-
sure.
3.
Start engine and engage the compressor clutch.
Compressors operating within specification
should be capable of reaching 350 psi (2415
kPa).
4.
Shut the system down immediately, once 350 psi
(2415 kPa) is achieved.
Denso A/C Compressor
Pressure Test
NOTE: This test is meant to be performed after
a failure has been repaired, which may have
caused damage to the compressor due to low
refrigerant or oil levels. Compressors cause re-
frigerant to flow through the system by creating
a pressure differential, high and low pressures.
The compressor pressure test must be perfor-
med with the refrigerant system discharged, and
the refrigerant lines disconnected.
If the A/C system is experiencing a low "high side"
pressure, or a high "low side" pressure, test the per-
formance of the compressor as follows.
1.
Place your thumb over the suction port of the
compressor and slowly rotate the compressor. An
even suction should be felt as the compressor is
turned.
2.
Place your thumb over the discharge port and
slowly rotate the compressor. An even pressure
should be felt as the compressor is turned.
3.
If an uneven pressure is felt on either the suction
or discharge port while turning the compressor,
internal damage has occurred, and the compres-
sor will not perform properly.
Heater and Air Conditioner Troubleshooting
83.00
Refrigerant System Tests
122SD and Coronado Workshop Manual, Supplement 9, June 2014
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