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SECTION 30 - QUICK START
• Variable Orifice control returns to standard and is
opened
• Oil Pump control is returned to standard and turns
off
If a Quick Restart did not occur within 30 seconds of
the end of Coastdown as described above, the next start
that occurs will be a QUICK NORMAL START as de-
scribed below.
Quick Normal Start
If a Quick restart does not occur within 30 seconds after
the end of Coastdown as described above, the next start
that occurs will be a Quick Normal Start. This is a start
that uses a Pre-lube but loading is faster than normal.
During the Pre-lube, a continuous open signal is given
to the PRV as soon as the oil pump run signal is en-
abled. This open signal will be sent until the Pre-lube
is complete, whereupon PRV control returns to normal
automatic control. The level Control and Oil Pump are
controlled during Pre-lube and System run as in normal
operation. At the completion of Pre-lube, a run com-
mand is sent to the VSD, the chiller enters System run
and the Quick Pulldown begins. The "Quick Pulldown
TABLE 24 - COMPARE A NORMAL START, QUICK NORMAL START, AND A QUICK RESTART.
NORMAL START
(STANDARD LOGIC)
Minimum Coastdown Time
150 sec (Q Compressors)
2 40 sec(J7,K7 Compressors)
150 sec(all other Compressors)
Chiller Off
PRV Closed
Variable Orifice Opened
Hot gas Closed
Pre-lube
PRV Closed
Variable Orifice Preset/Held
Hot gas Closed
VSD Run Signal Enabled
PRV Controlled by Capacity Control
Variable Orifice Preset/Held/Ramp
VSD to Start Frequency
Hot gas Standard Control
Slow Ramp-up of Speed
250
In Effect" LED on the QUICK START Screen illumi-
nates while the Quick Pulldown is in effect. The speed
command programmed as the VSD Start Frequency
setpoint is sent to the VSD. The speed will ramp up to
maximum frequency from this point at 4X the standard
control until it reaches the current set as the Quick Ramp
Current Threshold setpoint (20-80% FLA), whereup-
on it ramps at 2X standard control until it reaches the
standard current limiting over 80% FLA, whereupon it
ramps at standard rate to full speed. If at any time dur-
ing this ramping to full speed, if the Leaving Chilled
Liquid Temperature decreases to the temperature set by
the Quick Pulldown Setpoint Offset (0 to 10°F) setpoint,
the Pulldown Override Time (0 to 15 min) setpoint has
elapsed (whichever occurs first) or the motor current is
greater than 100% FLA, the Quick Pulldown terminates
and all VSD speed control returns to normal control.
Summary
The following table compares a Normal Start, Quick
Normal Start and a Quick Restart. The Normal Start
is that which has been the standard starting sequence
and that which occurs when the Quick Start feature is
disabled. This is a high level comparison and does not
include all details of Quick Start Mode.
QUICK NORMAL START
Minimum Coastdown Time
60 sec (Q Compressors)
150 sec (J7, K7 Compressors)
90 sec (All other Compressors)
Chiller Off
PRV Closed
Variable Orifice Opened
Hot gas Opened
Pre-lube
PRV Opened
Variable Orifice Preset/Held
Hot gas Opened
VSD Run Signal Enabled
PRV Controlled by Capacity Control
Variable Orifice Preset/Held/Ramp
VSD to Start Frequency
Hot gas Closed (Std Control)
Quick Ramp-up of Speed
Speed Control Returns to Standard
when LCHLT less than Active LCHLT
Setpoint + Quick Pulldown Setpoint
Offset OR when Run Time more than
Pulldown Override Time
JCI COMPANY CONFIDENTIAL
FORM 160.54-M1
ISSUE DATE: 10/25/2019
QUICK RESTART
Minimum Coastdown Time
60 sec (Q Compressors)
150 sec (J7, K7 Compressors)
90 sec (All other Compressors)
Coastdown
PRV Held (Open)
Variable Orifice Held (Open)
Hot gas Opened
No Pre-lube
VSD Run Signal Enabled
PRV Given Constant Open Signal
Variable Orifice Ramp
VSD to Start Frequency
Hot gas Closed (Std Control)
Quick Ramp-up of Speed
PRV and Speed Control Return to
Standard when LCHLT less than Ac-
tive LCHLT Setpoint + Quick Pulldown
Setpoint Offset OR when Run Time >
Pulldown Override Time
JOHNSON CONTROLS
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