JOHNSON CONTROLS
58
FORM 155.21-O1 (615)
OptiView Control Center
Low Leaving Chilled Liquid Temperature
The unit executes a cycling shutdown when LCHLT is
less than (LCHLT setpoint - LCHLT offset setpoint). If
the LOCAL entered LCHLT setpoint was changed in the
past 30 minutes, this cycling shutdown is NOT initiated
unless the LCHLT is less than both the resulting new
LCHLT setpoint and the previous LCHLT setpoint by the
offset value. If multiple LCHLT setpoint changes have
been made within 5 minutes of each other, the latest one
is considered a single change for this control. The unit
stops all pumps except the chilled liquid pump, closes
the shut-off valve and the control valve.
Recovery Condition
• LCHLT is greathan or equal to LCHLT se 2.
Power Failure Occurred
The unit was running and the panel power and was
off, the unit is configured to auto start after a power
failure.
Recovery Condition
• The unit will restart automatically.
Unit Shutdown by Remote Device
The unit is ready to start and the "Remote / Local Cy
-
cling" contact connected between I/O board TB4-1 and
TB4-13 opens. This message clears when the "Remote
/ Local Cycling" contacts close.
Recovery Condition
• "Remote / Local cycling" contact opens, the machine
restarts automatically if there is not any other active
cycling or safety shutdown.
Unit Shutdown by Multiunit Remote
This message is displayed when the "Multi-unit se-
quence" contact connected between I/O Board TB4-1
and TB4-9 opens. The message clears when the "Multi-
unit Sequence" contacts close.
Recovery Condition
• "Multi-unit cycling" contacts close, the machine
restarts automatically if there is not any other active
cycling or safety shutdown.
Safety Shutdown Messages
Auxiliary Safety Shutdown
The auxiliary safety shutdown contacts connected be-
tween I/O board TB4-1 and TB4-31 are open. If the
chiller was in RUN status, the chiller initiates a dilution
cycle.
Recovery Condition
• The auxiliary safety shutdown contacts are closed
and the unit switch is taken to STOP/RESET po
-
sition. The chiller continues dilution if it was in
progress and becomes ready to start.
Chilled Liquid Flow Switch Opened
The chilled water flow switch has been opened continu
-
ously for the safety duration. If the chiller was in RUN
status, the switch must be opened continuously for 2
seconds and then the chiller initiates limited dilution.
If the chilled liquid pump was commanded to run in
manual mode from the control panel and the unit was
not in RUN status, the switch must be opened continu-
ously for 30 seconds.
Recovery Conditions
• If the chiller was in RUN status at the time of the
event, and limited dilution has timed out (4 hours),
when the unit switch is taken to STOP/RESET posi
-
tion the chiller becomes ready to start.
• If the chiller was in RUN status at the time of the
event and the unit switch is taken to STOP/RESET
position before limited dilution has timed out (4
hours) the unit initiates dilution then the chiller
becomes ready to start.
• If the chiller was not in RUN status at the time of
the event, when the switch contacts close or call
for manual pump operation is ceased and the unit
switch is placed to STOP/RESET position the chiller
becomes ready to start.
Cond Flow Switch closed during
Limited Dilution
This shutdown occurs when the condenser water flow
switch has been closed continuously for 30 seconds
when the unit is performing a limited dilution cycle.
Recovery Condition
• The operator should review and resolve the problem,
place control in the STOP/RESET position, and run
manual dilution if necessary.
