valve to handle, HP air can then be aligned through a
5. Air receiver pressureIs it below the falling
reducing station to supplement the LP air system.
pressure set point, as it should be?
COMPRESSOR RUNS ONLY FOR A SHORT
Maintenance
PERIOD. Examine the following conditions as the
possible cause:
Because of the wide range of use, proper
maintenance of the LPACs is extremely important. All
of the maintenance requirements are really very easy to
water in the separator holding tank too low?
accomplish. Even though these requirements may seem
(Screw-type LPAC)
easy and almost insignificant, you should not
2. Compressor runs for only 5 to 12 seconds
underestimate their importance. If these procedures are
not performed correctly and in a timely manner,
Check for the following conditions (screw-type
long-range detrimental effects on the equipment will
LPAC):
result. Always use the PMS when accomplishing
a. Oil pressureIs it too low?
maintenance on LPACs. Remember, the PMS is only
sufficient to meet the minimum requirements. As a GS,
b. Injection water pressureIs it too low?
you must be aware of the more extensive requirements
c. CompressorIs it running in the wrong
that may be required by your type commander.
direction?
Troubleshooting
3. Compressor runs for only 12 to 15 seconds-Is
the oil pressure 100 low? (Reciprocating-type
Generally, as the operator you will not be equipped
LPAC)
to correct all malfunctions; however, you should be able
COMPRESSOR DOES NOT AUTOMATI-
to identify them when they occur and make a
CALLY UNLOAD OR STOP. Check the following
preliminary diagnosis of the probable cause. There are
components for the possible cause:
occasions when a malfunction can be caused by one or
more possible faults. Using fault logic diagrams and
1. Receiver air pressure switch-Is it operating? Is
flow charts, you should be able to investigate, isolate,
it at the proper setting?
and correct a malfunction with a minimum amount of
2. Compressor air intake butterfly valveIs it
compressor downtime. When you encounter troubles for
which the possible causes are not readily adaptable to a
closing properly? (Screw-type LPAC)
fault logic diagram, you can usually find specific
3. Ten-minute unloaded run timing relayIs it
explanations in the applicable manufacturer's technical
operational? (Screw-type LPAC)
manual.
4. Unloading solenoid valveIs it operational?
In the following paragraphs, we will discuss some
(Reciprocating-type LPAC)
common problems that may occur to both types of
LPACs and some key points to help you identify them
COMPRESSOR DOES NOT AUTOMATI-
and minimize equipment downtime. If we state a
C A L L Y START OR LOAD. Check these
problem or possible cause that refers to a specific LPAC
components:
type or model, we will indicate the type of model in
1. Receiver pressure switchIs it operational? Is it
parentheses.
at the proper setting?
C O M P R E S S O R WILL NOT START IN
MANUAL MODE. Check the following components
2. Compressor air intake butterfly valveIs it
for the possible cause of this malfunction:
opening properly? (Screw-type LPAC)
1. Power switchIs it operational?
3. Unloading solenoid valveIs it operational?
(Reciprocating-type LPAC)
2. FusesAre they blown?
AIR PRESSURE IS TOO HIGH AND
3. Last shutdownWas the last shutdown an
RECEIVER RELIEF VALVE IS OPENING. Check
automatic safety shutdown?
the following conditions:
4. Control panelDo the failure indicating lights
illuminate when start-up is initiated
1. Relief valveIs it set incorrectly? Is it defective?
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