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FORM 160.81-O1 (1020)
ISSUE DATE 10/05/2020
Temperature setpoint above the operator programmed
Base setpoint (see below). Programmable as either 10,
20, 30 or 40°F, with a default of 10°F, it is added to the
Base value to create a range over which the remote de-
vice can reset the setpoint. For example, if this setpoint
is programmed for 10°F and the operator programmed
value is 45°F, then the remote device can set the Leav-
ing Chilled Liquid Temperature setpoint over the range
45.0° to 55.0°F.
Local Leaving Chilled Liquid Temperature
Setpoint
Access Level Required: OPERATOR
This value allows the user to define the Leaving
Chilled Liquid Temperature that is to be maintained by
the chiller. It is programmable over the range of 38.0°F
to 70.0°F (water) or 20.0°F to 70.0°F (brine). If Smart
Freeze is enabled, the range is 36.0°F to 70.0°F (wa-
ter). A remote device can provide an analog signal (0 to
20mA, 4 to 20mA, 0 to 10VDC, or 2 to 10VDC) in An-
alog Remote mode, or PWM signal in Digital Remote
mode that changes the setpoint by creating an offset
above the operator programmed Base Leaving Chilled
Liquid Temperature setpoint. This offset may be de-
fined up to 10.0°F, 20.0°F, 30.0°F, or 40.0°F above the
Base setpoint (see the Remote Leaving Chilled Liquid
Temperature setpoint range description above). Addi-
tionally, a remote MicroGateway device (in ISN Re-
mote mode) can define the setpoint through a serial
data stream. In this case, the incoming setpoint is not
an offset that is applied to the locally programmed Base
setpoint value, but rather is the setpoint value itself.
Leaving Chilled Liquid Temperature Cycling
Offset - Shutdown
Access Level Required: OPERATOR
This value allows the user to specify the Leaving
Chilled Liquid Temperature at which the chiller will
shut down on a LEAVING CHILLED LIQUID –
LOW TEMPERATURE cycling shutdown. This is
done by defining an offset below the Leaving Chilled
Liquid Temperature setpoint. It is programmable over
a range of 1°F to 64°F below the setpoint, to a mini-
mum cutout of 36°F (water), 34°F (water with Smart
Freeze enabled) or 16°F (brine). It establishes the
minimum allowed temperature for the Leaving Chilled
Liquid Temperature and prevents over-cooling of the
building. Anytime the Leaving Chilled Liquid Tem-
perature setpoint is increased, the shutdown threshold
is 36.0°F (water) or 16.0°F (brine) for the next ten (10)
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW™ CONTROL CENTER
minutes. If Smart Freeze is enabled, the threshold is
34.0°F for the next 10 minutes. After ten (10) minutes
have elapsed, the shutdown threshold becomes the pro-
grammed setpoint value.
Leaving Chilled Liquid Temperature Cycling
Offset - Restart
Access Level Required: OPERATOR
This value allows the user to specify the Leaving Chilled
Liquid Temperature at which the chiller will restart af-
ter a shutdown on a LEAVING CHILLED LIQUID
– LOW TEMPERATURE cycling shutdown. This is
done by defining an offset above the Leaving Chilled
Liquid Temperature setpoint. It is programmable over a
range of 0°F to 70°F above the setpoint, to a maximum
restart value of 80°F. The chiller will automatically re-
start when this temperature is reached. This setpoint
can be used to reduce chiller cycling by delaying the
chiller restart until the cooling load has increased.
Remote Analog Input Range
Access Level Required: OPERATOR
This setpoint defines, for the Control Center, the re-
mote signal range applied for remote reset of the Leav-
ing Chilled Liquid Temperature setpoint and Current
Limit setpoint in Analog Remote mode. If the remote
signal is 0 to 10VDC or 0 to 20mA, this setpoint must
be programmed for 0 to 10VDC. If the remote signal
is 2 to 10VDC or 4 to 20mA, this setpoint must be pro-
grammed for 2 to 10VDC.
Local Motor Current Limit
Access Level Required: OPERATOR
Allows the user to specify the maximum allowed mo-
tor current (as a percentage of FLA). When the mo-
tor current reaches this value, the slide valve will not
be permitted to load further. If the motor current rises
above this value, the slide valve will unload to reduce
the current to this value.
Pulldown Demand Limit
Access Level Required: OPERATOR
Allows the user to specify the current limit value (as
a percentage of Full Load Amps) to which the chiller
will be limited during the specified pulldown limit
time. This value will override the Motor Current Limit
value during this time period. This function is used to
provide energy savings following chiller startup.
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