Table 55: Lag compressor control states
Control state
Description
Checking minimum rate, waiting
minimum rate time
When the 8 minute pulldown delay is finished, the chiller pulldown period continues
until the
Leaving Chilled Liquid Temperature
is within 2ºF of the
Leaving
Chilled Liquid Temperature Setpoint
. During this period, the Delta T Rate is
compared to the
Minimum Rate Setpoint
and the
Minimum Rate Time Setpoint
to determine if the lead compressor is meeting the load requirement. If the Delta T
Rate is less than the programmed
Minimum Rate Setpoint
for a period equal to the
Minimum Rate Time Setpoint
and the
Chiller Pulldown Limit Setpoint
is
above 50%, the lag compressor is brought on line.
Checking Minimum Rate
is displayed after the pulldown delay is finished and
until either the Delta T Rate is less than the
Minimum Rate Setpoint
(whereupon
Waiting Minimum Rate Time
is displayed), the chiller pulldown period is no longer
in effect (whereupon
Checking Maximum Delta T
is displayed) or the
Chiller
Pulldown Limit Setpoint
is set to 50% or less. When
Waiting Minimum Rate
Time
is displayed, it will be displayed until the chiller pulldown period has ended (at
which time
Checking Maximum Delta T
is displayed), the Delta T Rate is less than
the
Minimum Rate Setpoint
(at which time
Checking Minimum Rate
is again
displayed), the
Minimum Rate Time
has expired (whereupon the lag compressor is
brought on line and
Preparing Chiller for Lag Run
is displayed) or the
Chiller
Pulldown Demand Limit
is set to 50% or less.
Checking maximum Delta T,
Waiting maximum Delta T time
When the
Leaving Chilled Liquid Temperature
is within 2ºF of the
Leaving
Chilled Liquid Temperature Setpoint
, the chiller pulldown period ends
and the chiller steady state period begins. During this period, the
Temperature
Differential
is compared to the
Maximum Delta T Setpoint
and the
Maximum
Delta T Time Setpoint
to determine if the lead compressor is meeting the load
requirement. If the
Temperature Differential
exceeds the
Maximum Delta
T Setpoint
for a period equal to the
Maximum Delta T Time
and the
Chiller
Current Limit
is above 50%, the lag compressor is brought on line.
Checking Maximum Delta T
is displayed after the Chiller Pulldown Period is no
longer in effect and until the
Temperature Differential
exceeds the
Maximum
Delta T Setpoint
(at which time
Waiting Maximum Delta T Time
is displayed)
or the
Chiller Current Limit
is set to 50% or less. When
Waiting Maximum
Delta T Time
is displayed, it is displayed until the
Temperature Differential
does not exceed the
Maximum Delta T Setpoint
(at which time
Checking
Maximum Delta T
is displayed), the
Maximum Delta T Time
has expired (at which
time
Preparing Chiller for Lag Run
is displayed and the lag chiller is brought
on line) or the
Chiller Current Limit Setpoint
is set to 50% or less.
Preparing chiller for lag run
Displayed while bringing the lag compressor on line. Displayed during the prelube
period and until the discharge valve has fully opened (at which time
Waiting
Minimum Run Time
is displayed). When bringing the lag compressor on line, a
normal prelube is performed. However, the oil pressure transducer auto-zeroing is not
performed. The offset calculations done during the lead compressor prelube are used.
The lag compressor prelube is fixed at 50 seconds.
Waiting minimum run time
Displayed for the first 30 minutes after the lag compressor is brought line. Once both
compressors are running, they are run for at least 30 minutes (unless the anti-recycle
feature has been disabled, a fault is detected or a Local or Remote stop is received).
Checking minimum load, waiting
minimum load time
After the 30 minute
Minimum Run Time
waiting period, the lag compressor will
be shutdown if the lead compressor motor current goes below the
Low Load
Setpoint
for a period equal to the
Low Load Time Setpoint
. After the 30 minute
Minimum Run Time
has elapsed,
Checking Minimum Load
is displayed until the
lead compressor motor current decreases below the
Low Load Setpoint
(at which
point
Waiting Minimum Load Time
is displayed).
Waiting Minimum Load Time
is
displayed until the lead motor current is no longer less than the
Low Load Setpoint
or the
Minimum Load Time
has expired (whereupon a soft shutdown is performed on
the lag compressor and
Unloading Before Shutdown
is displayed).
Unloading before shutdown
Displayed while the pre-rotation vanes are closing during a Soft Shutdown of the lag
compressor. If the decision is made to shutdown the lag compressor while continuing
to run the lead compressor, a Soft Shutdown is performed on the lag compressor.
Model YD Mod D with OptiView Control Center
70
Содержание YD Mod D
Страница 2: ...2 Model YD Mod D with OptiView Control Center...
Страница 8: ...Nomenclature Model YD Mod D with OptiView Control Center 8...
Страница 17: ...Figure 2 Chiller operation flow chart 17 Model YD Mod D with OptiView Control Center...
Страница 18: ...Figure 2 Chiller operation flow chart Model YD Mod D with OptiView Control Center 18...
Страница 19: ...Figure 2 Chiller operation flow chart 19 Model YD Mod D with OptiView Control Center...
Страница 20: ...Figure 2 Chiller operation flow chart Model YD Mod D with OptiView Control Center 20...
Страница 21: ...Figure 2 Chiller operation flow chart 21 Model YD Mod D with OptiView Control Center...
Страница 22: ...Figure 2 Chiller operation flow chart Model YD Mod D with OptiView Control Center 22...
Страница 150: ...Figure 57 Sample printout status Model YD Mod D with OptiView Control Center 150...
Страница 151: ...Figure 57 Sample printout status 151 Model YD Mod D with OptiView Control Center...
Страница 152: ...Figure 58 Sample printout setpoints Model YD Mod D with OptiView Control Center 152...
Страница 153: ...Figure 58 Sample printout setpoints 153 Model YD Mod D with OptiView Control Center...
Страница 154: ...Figure 59 Sample printout schedule Model YD Mod D with OptiView Control Center 154...
Страница 155: ...Figure 60 Sample printout sales order 155 Model YD Mod D with OptiView Control Center...
Страница 156: ...Figure 61 Sample printout history Model YD Mod D with OptiView Control Center 156...
Страница 157: ...Figure 61 Sample printout history 157 Model YD Mod D with OptiView Control Center...
Страница 159: ...Figure 64 Sample printout custom screen report 159 Model YD Mod D with OptiView Control Center...