OMM 1008-1
65
StageMode settings can be NORMAL, HI EFF, PUMP, and STANDBY as determined by the Stage Mode
setpoint.
NORMAL has the auto-balance sequence that starts compressors with least starts and stops compressors with
most hours, in sequence, providing all compressors have the same sequence number. If they have different
sequence numbers, say 1, 2, 3, 4; they will always start in that sequence. That is, sequence number will take
precedence over auto-balance sequencing.
HI EFF is used with multiple chillers and runs one compressor per chiller when ever possible.
PUMP starts all compressors on the same chiller first, starting with the chiller with the compressor with the
least starts (or by sequence number if they are different).
STANDBY is used in multi-compressor systems and reserves a compressor to come on only if there is a
failure of another compressor in the system and the standby compressor capacity is required to maintain
chilled water temperature.
StageSequence is set for each compressor:
•
•
In NORMAL or STANDBY Mode, all compressors can have the same number or a number from 1 up to
the total number of compressors. Sequence number has priority over other considerations. If four
compressors in a system are given the sequence numbers 1 through 4, they will always start in that order.
With the same number they will auto-sequence.
•
•
In HI EFF or PUMP Mode, all compressors must have the same sequence number.
•
•
Max Comprs ON limits the number of compressors allowed to run in multi-compressor systems. It
provides a "floating standby" compressor. All compressor controllers must have the same setting for this
setpoint.
SET COMP#N SPs (3)
StageDeltaT =1.0°F
Stop-Start =03min
Start-Start =40min
SET COMP#N SPs (4)
Full Load = 300sec
Name Plate RLA 085
Full Load timing is one of several “full load flags,” parameters that indicate a compressor is at full load.
SET COMP#N SPs (5)
Nom Capacity=0100T
Hotgasbypass =
Ignore hot gas bypass setting. Magnitude
chillers are not so equipped.
SET COMP#N SPs (6)
IntrLokTmr=010sec
UnloadTimer=030sec
Max Str LWT = XXX
°
°
°
°
F
Ignore Max Str LWT setting.