Refrigerant System Clean-Out After Compressor Failure - PREVOST H3-41 Maintenance Manual

4. When disconnecting any fitting in the
refrigeration system, the system must first
be discharged of all refrigerant. However,
proceed very cautiously, regardless of
gauge readings. If there happens to be
liquid refrigerant in the line, disconnect
fittings very slowly, keeping face and hands
away so that no injury can occur. If pressure
is noticed when fitting is loosened, allow it
to bleed off very slowly.
WARNING
Always wear safety goggles and gloves when
opening refrigerant lines.
5. In the event that any line is opened to the
atmosphere, it should
capped to prevent entrance of moisture and
dirt.
6. The use of the proper wrenches when
making connections on O-ring fittings is
important. The use of improper wrenches
may damage the connection. The opposing
fitting should always be backed up with a
wrench to prevent distortion of connection
lines or components. When connecting the
flexible hose connections, it is important
that the swaged fitting and the flare nut, as
well as the coupling to which it is attached,
be held at the same time using three
different wrenches to prevent turning the
fitting and damaging the ground seat.
7. The O-rings and seats must be in perfect
condition. The slightest burr or piece of dirt
may cause a leak.
8. O-rings and gaskets should be coated
with refrigeration oil and installed on the
line before the line is inserted into the fitting
to prevent damaging the O-ring. If leaks are
encountered at the couplings or connectors,
no attempt should be made to correct the
leaks by tightening the connections beyond
the recommended torque. The O-rings are
designed to seal at the specified torque and
overtightening the connection does not
result in a satisfactory and permanently
sealed connection. The connection must be
disassembled and the cause of the leak
(damaged O-ring, defective lines, etc.)
corrected. Use new O-ring.
SECTION 22: HEATING AND AIR CONDITIONING
be immediately
PA1621 Maintenance Manual All Series | Revised February 2019
6.5.3 Refrigerant System Clean-Out After
Compressor Failure
Although the vast majority of reciprocating
refrigerant compressors manufactured today are
extremely reliable, a small percentage do fail.
These failures usually result in minor or
extensive system contamination depending on
the severity of the failure. When an open type
compressor becomes damaged internally, this
provokes small particles of bearings, steel,
brass, copper, and aluminum and, in severe
cases, carbonized oil, which could contaminate
the system. To prevent repeated failures, the
problem which caused the failure should be
corrected, and depending upon the severity of
the failure, the system should be thoroughly
cleaned out using
procedures mentioned.
Determining Severity of Failure
The severity of compressor failure can be
categorized as minor or major. A failure is
considered minor when the contamination is
limited to the compressor with little or no system
contamination. A major failure, or burnout,
results in extensive system contamination as
well as compressor damage. Extensive system
contamination can
withdrawing a small sample of compressor oil
and checking its color, odor and acidity. A
Virginia Chemical "TKO" one step acid test kit is
one of several compressor oil test kits that may
be used. A high acid content would indicate a
major failure or burnout. A small amount of
refrigerant gas may
characteristic burned odor would also indicate
severe system contamination.
Clean-out after Minor Compressor Failure
1. Be sure to correct the problem which
caused the failure.
2. Change liquid line filter-dryer.
3. Run the unit for 2 hours on high speed cool
only.
4. Check compressor oil level to ensure
compressor is not overcharged with oil.
Sometimes a significant amount of oil is
pumped out of the compressor to other
parts of the system when a compressor
fails. This oil will return to the replacement
compressor when it is started, causing an
overcharge of oil in the sump of the
replacement compressor. In this case, it is
one of the cleanout
be determined by
be discharged.
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A