CONTROLS TROUBLESHOOTING GUIDE
Symptom
Display indicates “REMOTE STOP
Display indicates “SHUTDOWN”
Compressor runs, but
does not load
Compressor runs,
unloads at low pressure
Compressor does not
modulate
Compressor cycles rapidly
between load and unload
Display is illegible
Erratic pressures
in SEQUENCE only
Compressor cycles rapidly
in SEQUENCE mode only
LOW OIL PRESSURE
in SEQUENCE mode only
Pressure display error
Recommended Action
The controller is provided with an input for user-furnished remote con-
trols. This display indicates that 120 volt is removed from terminal 6 of the
terminal strip. Check all connections of the factory installed jumper, or the
customer-provided controls, if applicable.
If the display indicates “SHUTDOWN”, refer to the shutdown trouble-
shooting section for assistance. In addition to the messages shown, there
are several internal and system diagnostics performed by the controller.
Consult the factory for additional assistance.
In the CONSTANT RUN and LOW DEMAND modes, the compressor will
not load untilthe pressure drops below reset pressure. Refer to the operat-
ing instructions for further information, If pressure is below the reset pres-
sure, check that the inlet valve operates freely. Check that the IVO and
IVC valves are wired and operating properly.
If the inlet valve closes at low pressure, check the wiring to the blowdown
valve and the piping and check valves in its discharge line.
The ES controller operates the inlet valve to maintain pressure near the
set pressure, matching delivery to demand. If the pressure continues to
rise above set pressure, check that the inlet valve operates freely, and that
control air is supplied to the IVC valve. If modulation does not close the
valve, itwill be closed during a blowdown as pressure approaches the high
pressure limit.
The external air receiver should be sized appropriately to prevent rapid
cycles. The rapid response time in CONSTANT RUN mode will operate
with small receivers, but any plant air system will operate more efficiently
with adequately sized storage. Refer to the operating instructions for fur-
ther information.
Extra segments or “ghosting” of characters indicates damage probably
from excessive high voltage. Replace the controller, and install protection
to prevent further damage to electrical equipment,
The sequencing system transmits low-level signal between units to com-
municate pressures. Units must be properly grounded to a good ground
system, the communications cable should use only appropriate quality
cable, and the cable should be run in its own conduit.
In the sequence mode, the operating system requires all compressors be
piped directly to receiver, such that all transducers sense the same pres-
sure. Check valves or restrictions between compressors and the storage
will cause system instability. Run units inAUTOMATIC mode until the sys-
tem is corrected.
If this shutdown occurs in the sequence mode only, it indicates instability
due to rapid changes in pressure of the system. Remove restrictions be-
tween the compressor and receiver, increase receiver size if necessary
to slow down the pressure,swings.
Accuracy of the pressure display and controls requires that the controller
and transducers be calibrated together. This MUST be done with no pres-
sure at the transducer, or errors will
occur. This is easiest to check with
all pressure removed. All pressure displays should indicate Opsi (0.0 Bar)
+/- 1 PSI. If the display indicates greater pressures, recalibrate the sys-
tem as instructed in the configuration adjustments. Note: reservoir pres-
sure may drop below zero psig when the compressor is stopped, but will
return slowty to zero as the vacuum is relieved.
13-9/10-641 Page 65
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