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Auto. Restart After Power Failure
When an autorestart condition occurs, each chiller may have a delay added to the start-up
sequence, depending on its lead/lag configuration. The lead chiller does not have a delay. The
lag chiller has a 45-second delay. The standby chiller has a 90-second delay. The delay time is
added after the chiller water flow verification. The PIC controls ensure that the guide vanes are
closed. After the guide vane position is confirmed, the delay for lag and standby chiller occurs
prior to energizing the oil pump. The normal start-up sequence then continues. The auto. restart
delay sequence occurs whether the chiller is in CCN or LOCAL mode and is intended to stagger
the compressor motors from being energized simultaneously. This will help reduce the inrush
demands on the building power system.
Ice Build Control
Ice build control automatically sets the chilled WATER/BRINE CONTROL POINT of the
machine from normal operation set point temperature to a temperature where an ice building
operation for thermal storage can be accomplished.
Note:
For ice build control to properly operate, the PIC controls must be placed in CCN mode.
See Figure 16 and Figure 17.
The PIC can be configured for ice build operation. Configuration of ice build control is
accomplished through entries in the Config table, Ice Build Setpoint table, and the Ice Build
Time Schedule table. Figure 16 and Figure 17 show how to access each entry.