Filter
Top Products
65
CVHE-SVU01E-EN
Now that the compressor motor
(4M1) is running in the ‘‘Delta’’
configuration, the inlet guide vanes
will modulate, opening and closing
to the chiller load variation by
operation of the stepper vane motor
actuator (4M2) to satisfy chilled water
setpoint. The chiller continues to run
in its appropriate mode of operation:
Normal, Softload, Limit Mode,
etcetera.
If the chilled water temperature drops
below the chilled water set point by
an amount set as the ‘‘differential to
stop’’ setpoint, a normal chiller stop
sequence is initiated as follows:
(Refer to Figure 10.)
1. The inlet guide vanes are driven
closed up to 50 seconds.
2. After the inlet guide vanes are
closed, the stop relay (2A1-J10) and
the condenser water pump relays
(1A5-J2) open to turn off. The oil
and refrigerant pump motor (4B3)
will continue to run for 3 minutes
post lube while the compressor
coasts to a stop. The chilled water
pump will continue to run while
the Main processor module (1A22)
monitors leaving chilled water
temperature preparing for the next
compressor motor start based on
the ‘‘differential to start’’ setpoint.
If the STOP key is pressed on the
operator interface, the chiller will
follow the same stop sequence as
above except the chilled water pump
relay (1A5-J2) will also open and stop
the chilled water pump after the
chilled water pump delay timer has
timed out after compressor shut
down.
If the “Immediate Stop” is initiated, a
panic stop occurs which follows the
same stop sequence as pressing the
STOP key once except the inlet guide
vanes are not sequence closed and
the compressor motor is immediately
turned off.
Control Sequence
of Operation