LG RCAW Operation & Maintenance Manual page 40

Operation
Delay control for the chiller is summarized in the below picture. There are two essential delays, stop to start
delay and oil pre-heating delay in the picture. The stop to start delay is the duration between the stoppage of
the compressor and the restart of the compressor. The factory setting value of the delay is 10 minutes and con-
figurable through delay setting of the HMI unit. The delay is designed to protect the compressor from frequent
starting. The other delay, oil pre-heating delay is activated only after power-on reset. The delay is also config-
urable through user setting of the HMI unit. The delay is designed to protect the cooling cycle of the chiller from
improper oil circulation especially at low ambient condition
Stop
Stop
Delay
Delay
Fan
Fan
Stop
Stop
Delay
Delay
Start Delay
Start Delay
Compressor Run
Compressor Run
Water Pump Run
Water pump run
START
START
Condenser Fan Run
Condenser fan run
Oil Pre-heating
Stop to
Delay
Start
Stop to Start
Delay
Delay
Power on
Reset
Fig. 18
During running compressor, the condenser fans are controlled to get proper high pressure side condition of the
cooling cycle. The control points of the condenser fans are determined by refrigerant leaving condenser temper-
ature, and they are configurable through parameter setting of the HMI unit.
40 Chiller Air-cooled Screw