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TM5-4120-375-14
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LOCATION/ITEM
ACTION
REMARKS
TEST
7.
DIAGNOSING COMPRESSOR MOTOR BURNOUT
It. is important to diagnose the type of compressor motor failure for two reasons
Simple failure, without motor burnout, does not require the extensive cleaning
of the entire refrigeration system that burnout requires.
Also, motor burnout
indicates other problems that have contributed to the failure, and these pro-
blems must be corrected or avoided to prevent repetition of the burnout. After
removal of a bad compressor from the refrigeration system, remove all external
tubing and tip the compressor towards the discharge port to drain a small
quantity of oil into a clear glass c o n t a i n e r.
If the oil is clean and clear,
and does not have an acrid smell, the compressor did not fail because of
motor burnout. If the oil is black, contains sludge and has an acrid odor,
the compressor failed because of motor burnout, and the refrigeration system
must be cleaned to prevent residual contaminates from causing repeated
burnouts when the compressor is replaced.
8 .
CLEANING OUT THE REFRIGERATION SYSTEM AFTER BURNOUT
WARNING
Avoid contact with refrigerant. Acid
from contact with refrigerant.
burns could result
You must clean the entire refrigeration system after a burnout has occurred,
since contaminates will have been carried to many corners and restrictions in
the piping and fittings.
These contaminates will soon mix with new refrigerant
gas and compressor oil to cause repeated burnouts. To clean the system
thoroughly, act as follows:
a .
b .
c .
d .
Remove the filter-drier in accordance with paragraph 5-29 and blow
down each leg of the refrigeration system. To do this, connect a
cylinder of dry nitrogen (Item 8, table D-1)to each filter-drier
connection, in turn, and open the cylinder shutoff valve for at least
30 seconds at 50 psig (3.5 kg cm 2) pressure.
Connect the two filter-drier fittings with a jumper locally manufactured
from refrigerant tubing and fittings, and install a pump, reservoir and
filter in place of the compressor.
Disassemble expansion valve and quench valve and temporarily remove the
valve cages. Re-install shell of power assembly, using a gasket
between power assembly and body to prevent leakage. Tag and retain valve
cages for use at reassembly.
Disassemble solenoid valve in accordance with paragraph 5-35.
5-89
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