Sterlco GC Series Central Chiller - Manual (Page 47)

GC Series Central Chillers Chapter 6: Troubleshooting 47 of 79
Problem Possible cause Solution
Compressor not operating
efficiently.
Call service.
Unit under-sized for application. Call sales rep
Troubleshooting Warnings and Faults from the PLC
Controller Alarm Possible Cause Solution
Compressor Fault Compressor Internal Overload Fault Allow time to cool and reset, then
check for high/low voltage. It must be
within ±10% of the nameplate rating.
Compressor Motor Circuit
Protector Open Verify switch is in the “ON” position
Verify amp value is at its highest
Check for high/low line voltage. It
must be within ±10% of the nameplate
rating
Discharge Pressure Sensor Failure Packard connector separated from
sensor Reconnect wire connector to sensor
Input to PLC is missing Verify wiring at PLC.
Faulty sensor cable Replace cable
Faulty sensor Replace sensor
VFD Fault See Troubleshooting the ABB
Variable Speed Drive below
See Troubleshooting the ABB Variable
Speed Drive below
Fan VFD fuses blown Replace fuses
Fan motor overload tripped Reset overload/verify overload setting
Input to PLC is missing Verify wiring at digital input ID4 at
PLC
High Discharge Pressure Fault
(Discharge pressure has exceeded
fault setpoint)
See VFD Fault above See VFD Fault above
Condenser inlet temperature too
high
Contact ACS Group Aftermarket
Service for assistance
Refrigerant overcharge Contact refrigeration technician about
removing refrigerant as needed
Dirty condenser Clean condenser
Fan motor failure Verify fan motor operation, replace as
needed
No analog output from PLC Verify wiring at analog output J4 per
print.
Verify VFD AI Type selector switch is
in the U position.
High Discharge Pressure Switch
(Discharge pressure has exceeded
switch 575 psig setting) Input to PLC is missing Verify wiring at digital input ID2 at
PLC
VFD Fault See VFD Fault above
Condenser inlet temperature too
high
Contact ACS Group Aftermarket
Service for assistance
Refrigerant overcharge Contact refrigeration technician about
removing refrigerant as needed
Dirty condenser Clean condenser
Fan motor failure Verify fan motor operation, replace as
needed
No analog output from PLC Verify wiring at analog output J4 per
print.
Verify VFD AI Type selector switch is
in the U position.
High Suction Pressure Fault
(Suction pressure has exceeded
fault setpoint) Load may be too high for chiller Contact your sales representative for
assistance.
Low Discharge Pressure Fault
(Discharge pressure has fallen
below fault setpoint) Condenser inlet temperature too
low Contact ACS Group Aftermarket
Service for assistance
VFD fault See VFD Fault above
Condenser water regulating valve
open
Verify analog output at Y1