Table 8 — LID Primary and Secondary Messages and Custom Alarm/Alert Messages
with Troubleshooting Guides (cont)
N. OTHER PROBLEMS/MALFUNCTIONS
DESCRIPTION/MALFUNCTION PROBABLE CAUSE/REMEDY
Chilled Water/Brine Temperature
Too High (Machine Running)
Chilled water set point set too high. Access set point on LID and verify.
Capacity override or excessive cooling load (machine at design capacity).
Check LID status messages. Check for outside air infiltration into condi-
tioned space.
Condenser temperature too high. Check for proper flow, examine cooling
tower operation, check for air or water leaks, check for fouled tubes.
Refrigerant level low. Check for leaks, add refrigerant, and trim charge.
Liquid bypass in waterbox. Examine division plates and gaskets for leaks.
Guide vanes fail to open. Use Control Test to check operation.
Chilled water control point too high. Access control algorithm status and check
chilled water control operation.
Guide vanes fail to open fully. Be sure that the guide vane target is released.
Check guide vane linkage. Check limit switch in actuator. Check that sensor
is in the proper terminals.
Chilled Water/Brine Temperature Too Low (Machine
Running)
Chilled water set point set too low. Access set point on LID and verify.
Chilled water control point too low.Access control algorithm status and check
chilled water control for proper resets.
High discharge temperature keeps guide vanes open.
Guide vanes fail to close. Be sure that guide vane target is released. Check
chilled water sensor accuracy. Check guide vane linkage. Check actuator
operation.
Chilled Water Temperature Fluctuates. Vanes Hunt Deadband too narrow. Configure LID for a larger deadband.
Proportional bands too narrow. Either INC or DEC proportional bands should
be increased.
Loose guide vane drive. Adjust chain drive.
Defective vane actuator. Check through Control Test.
Defective temperature sensor. Check sensor accuracy.
Low Oil Sump Temperature While Running
(Less than 100 F [38 C])
Check for proper oil level (not enough oil).
At Power Up, Default Screen Does NotAppear, ‘‘Tables Load-
ing’’ Message Continually Appears
Check for proper communications wiring on PSIO module. Check that the
COMM1 communications wires from the LID are terminated to the COMM1
PSIO connection. Check for ground or short on CCN system wiring.
SMM Communications Failure Check that PSIO communication plugs are connected correctly. Check SMM
communication plug. Check for proper SMM power supply. See Control Mod-
ules section on page 95.
High Oil Temperature While Running Check for proper oil level (too much oil). On hermetic EX compressors, check
that TXV valve is operating properly. On hermetic or open-drive FA com-
pressors, check water supply to oil cooler.
Blank LID Screen (Minimal Contrast Visible) Increase contrast potentiometer. See Fig. 50. Check red LED on LID for
proper operation, (power supply). If LED is blinking, but green LED’s are
not, replace LID module, (memory failure). Check light bulb if backlit model.
‘‘Communications Failure’’ Highlighted Message At
Bottom of LID Screen
LID is not properly addressed to the PSIO. Make sure that ‘‘Attach to Net-
work Device,’’ ‘‘Local Device’’ is set to read the PSIO address. Check LED’s
on PSIO. Is red LED operating properly? Are green LED’s blinking? See
control module troubleshooting section.
Control Test Disabled Press the ‘‘Stop’’ pushbutton. The PIC must be in the OFF mode for the
Control Test to operate. Clear all alarms. Check line voltage percent on Sta-
tus01 screen. The percent must be within 90% to 110%. Check voltage in-
put to SMM, calibrate starter voltage potentiometer for accuracy.
Vanes Will Not Open in Control Test Low pressure alarm is active. Put machine into pumpdown mode or equal-
ize pressure. Check guide vane actuator wiring.
Oil Pump Does Not Run Check oil pump voltage supply. Cooler vessel pressure under vacuum.
Pressurize vessel. Check temperature overload cutout switch.
LID Default Screen Does Not Update This is normal operation when an alarm is present. The screen freezes the
moment the alarm is activated to aid in troubleshooting. The Status01 screen
provides current information.
Machine Does Not Stop When the STOP Button is Pressed The STOP button wiring connector on the LID module is not properly con-
nected or the machine is in soft stop mode and the guide vanes are
closing.
LID Screen Dark Light bulb burned out. Replace as needed.
92
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