RLC-SVU01B-E4
14
Ice Building to Normal Transition (2)
Ice Building is Complete (2)
Auto (1)
Waiting For Evap Water Flow (2)
Waiting for Need to Cool (2)
Starting (1)
No Sub Modes Running (1)
Unit is Building Ice (2)
Running - Limited (1)
Capacity Limited by High Evap Water Temp
(2)
The chiller is inhibited from running for a brief period of time if it is
commanded from active ice building mode into normal cooling mode
via the ice building hardwired input or Tracer. This allows time for the
external system load to "switchover" from an ice bank to the chilled
water loop, and provides for a controlled pull down of the loop's
warmer temperature. This mode is not seen if the ice making is
automatically terminated on return brine temperature per the mode
below.
The chiller is inhibited from running as the Ice Building process has
been normally terminated on the return brine temperature. The chiller
will not start unless the ice building command (hardwired input or
BAS command) is removed or cycled.
The chiller is not currently running but can be expected to start at any
moment given that the proper conditions and interlocks are satisfied.
Further information is provided by the sub-mode:
The chiller will wait up to 4 minutes in this mode for evaporator water
flow to be established per the flow switch hardwired input.
The chiller will wait indefinitely in this mode, for an evaporator
leaving water temperature higher than the Chilled Water Setpoint plus
the Differential to Start.
The chiller is going through the necessary steps to allow the lead
circuit and lead compressor to start.
At least one circuit and one compressor on the chiller are currently
running. Further information is provided by the sub-mode:
The chiller is running in the Ice Building Mode, and either at or
moving towards full capacity available. Ice mode is terminated either
with the removal of the ice mode command or with the return brine
temperature falling below the Ice Termination Setpoint.
At least one circuit and one compressor on the chiller are currently
running, but the operation of the chiller as a whole is being actively
limited by the controls.
This mode will occur if both the OA temperature is above -4.4°C and
the Evaporator Leaving Water Temperature is above 23.9°C as is often
the case in a high temperature pull-down. While in this mode, no
compressors will be allowed to load past their minimum load
capacity step, but it will not inhibit compressor staging. This mode is
necessary to prevent nuisance trips due to Compressor Overcurrent
or High Pressure Cutout. Reasonable pull-down rates can still be
expected despite this limit.
Controls Interface
(1) Top level mode
(2) Sub-mode