247
FORM 160.54-M1
ISSUE DATE: 10/25/2019
JOHNSON CONTROLS
JCI COMPANY CONFIDENTIAL
30
The Quick Start feature is useful in data center and pro-
cess control applications where it is desirable to re-estab-
lish cooling as fast as possible after a shutdown or power
failure. This feature, when enabled, allows quicker starts
and restarts than normal control. It does this by reduc-
ing the time cycle for chiller restart and once running,
loading the chiller as fast as possible. After the chiller is
running and has met a specified setpoint or a specified
period of time has elapsed, control returns to normal.
In order to use this feature, the chiller must be equipped
with a Variable Speed Drive (VSD) (in Modbus Proto-
col configuration) or a medium Voltage VSD. The low
inrush current of a VSD allows more starts per hour
and allows the chiller to start with a more open vane
position.
Although not required, the hot gas bypass option is rec-
ommended, as it will allow the chiller to startup more
smoothly with less chance of surging.
QUICK START MODES
The quick start feature has two different start modes:
•
Quick Restart –
When a chiller shuts down, if
certain conditions are met at the completion of
coastdown (within 30 seconds thereafter), the
VSD is started immediately with no pre-lube. The
vanes are given a constant open pulse and after the
VSD achieves its start frequency, the speed ramp
rate is faster than with normal control.
•
Quick Normal Start –
If the conditions for a
quick restart are not met, the next time the chiller
is started, it has a pre-lube period just like a nor-
mal start, however the vanes will begin to open
at the beginning of pre-lube, instead of waiting
until system run. At the completion of pre-lube,
the VSD is started and after the VSD achieves its
Start Frequency, the speed ramp rate is faster than
with normal control.
Although an Uninterruptible Power Supply (UPS) is
not required for the quick start feature, powering the
OptiView Control Center and VSD (except for the trig-
ger board) with 115 VAC from a UPS will reduce the
time to restart after a power failure due to elimination
of the OptiView reboot time. This provides the fastest
possible ability to start or restart after generator or util-
ity power is restored.
SECTION 30 - QUICK START
(SOFTWARE VERSION C.OPT.01.21.307 AND LATER)
The quick start feature must be enabled per the proce-
dure below to make it operational. There are certain
requirements and limitations applied that determine if
quick start can be enabled.
Once enabled, all setpoints and parameters related
to this feature are displayed on the QUICK START
screen, accessible from the SETPOINTS screen when
logged in at SERVICE access level.
If it is desired to use the quick start fea-
ture while heat pump duty is enabled,
quick start is only available when heat
pump duty operational mode setpoint is
set to cooling mode. When the heat pump
duty operational setpoint is set to heat-
ing mode, quick start is automatically
disabled.
SETPOINTS
The following setpoints are listed on the QUICK
START Screen. Use the CHANGE SETPOINTS key
and UP/DN Arrow keys to place a green box around
the desired setpoint to be changed. Then press the
key. A box will appear with the allowable values. En-
ter/Select the desired value and press the
key.
Quick Start Mode
(Enabled, Disabled; default Disabled)
This setpoint is used to enable and disable the quick
start feature. It can only be enabled when the motor
drive type setpoint is set to VSD and the Motor Com-
munications Protocol is set to Modbus. Or, the Motor
Drive Type setpoint is set to MVVSD. If heat pump
duty is enabled, the Quick Start feature can only be en-
abled when the Heat Pump Operational Mode setpoint
is set to COOLING. The default is Disabled.
Quick Start can only be enabled using an ADMIN
password. When logged in at ADMIN access level, a
QUICK START key will appear on the SETPOINTS
Screen. Pressing this key will navigate to the QUICK
START Screen where this setpoint is used to enable/
disable the feature.
Quick start can be disabled when logged in at SERVICE
access level. However, once disabled, it requires an
ADMIN password to enable it again, as explained above.