LG RCWW-1 Operation & Maintenance Manual page 68

Alarm
Specific alarm identification method and potential cause of the issue are listed below. To cancel and
recover the alarm, remove the cause and delete the alarm detail.
Emergency alarm means that the operator pressed the emergency switch installed on the door of
the control panel. This switch input means that the switch input is open, which is normally closed.
When the emergency switch is open, the output power to control the output from the PLC is discon-
nected. Turn the emergency switch in clockwise direction to correct the alarm.
5E relay and voltage monitoring relay send the alarm signal when there is an issue with the power.
This issue includes over-voltage, under-voltage, reverse phase, phase loss and voltage unbalance.
In case of phase loss alarm, check whether all the fuses are not melted for the power check.
Water flow issue means that there is no water flow or more than 30% of the flow is short from the
set value. To resolve this issue, water pump error and insufficient water flow issues must be
checked simultaneously.
Pressure issue means that the high pressure switch or low pressure switch is tripped. These are
included in the dual input switch. In case of any issue, first check whether there is an appropriate
amount of refrigerant within the chiller. If there is no issue with the amount of refrigerant, the conta-
minated heat exchanger could be the cause. Consider that coolant outlet temperature range oper-
ates 20°C~40°C.
Oil issue means that there is no oil flow from the oil separator to the compressor or the amount of oil
in the oil separator is too low. This alarm can be checked after the delay time set by the user after
the compressor operates.
Delay can be adjusted through the alarm delay setting of HMI device. Insufficient oil must be
checked first. If the chiller operates at low ambient temperature without properly preheating the
device, the large amount of oil can be left in the evaporator rather than in the oil separator. In this
case, the oil from the evaporator must be collected to the oil separator.
The low differential pressure between the evaporator and condenser must be checked through the
pressure as the appropriate oil circulation is not ensured.
M1 and M2 are magnet contactors for screw compressor. The malfunctions of the magnet contactor
mean that the OCR trip occurred due to the overload condition and the problem of the magnetic
contactor itself.
INT69 issue means that abnormally high temperature for the motor coil or compressor discharge
inside the compressor terminal box.
Chiller Water-cooled Screw - 68 -