York YR Manual page 29

FORM 160.81-O1 (1020)
ISSUE DATE 10/05/2020
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).
(Microboard Program Jumper J35 must be removed for
Brine cooling applications). If Smart Freeze (see below)
is enabled, the range is 36.0°F to 70.0°F (water). If Ice
Storage is ON and wanted, the range is 20°F to 32°F
(brine). A remote device can provide an analog signal
(0 to 20mA, 4 to 20mA, 0 to 10VDC or 2 to 10VDC)
in Analog Remote mode, or PWM signal in Digital
Remote mode that changes the setpoint by creating an
offset above this base or lowest setting allowed for the
Leaving Chilled Liquid Temperature setpoint. This off-
set may be defined up to 10, 20, 30, or 40°F above this
base setpoint (see the Remote Leaving Chilled Liquid
Temperature Setpoint Range description above). Addi-
tionally, a MicroGateway (in ISN Remote mode) can
define the setpoint through a serial data stream. In this
case, the incoming setpoint is not an offset that is ap-
plied to this 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 minimum cut-
out of 36°F (water), 34°F (water with Smart Freeze
enabled) or 16°F (brine). It establishes the minimum
allowable temperature for the Leaving Chilled Liquid
Temperature and prevents over-cooling of the build-
ing. Anytime the Leaving Chilled Liquid Temperature
setpoint is increased, the shutdown threshold is 36.0°F
(water) or 16.0°F (brine) for the next ten (10) minutes.
If Smart Freeze (see below) 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.
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW™ CONTROL CENTER
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 60°F above the setpoint, to a maxi-
mum restart value of 80°F. If Ice Storage mode is ON,
there are two different Restart setpoints employed:
• One is programmed and will be in effect when the
Leaving Chilled Liquid Temperature setpoint is
less than or equal to 32.0º F.
• The other is programmed and will be in effect
when the setpoint is more than 32.0ºF. Each can
be programmed to a different value.
The chiller will automatically restart when this tem-
perature is reached. This setpoint can be used to reduce
chiller cycling by delaying the chiller restart until the
cooling load has increased.
Brine Low Evaporator Cutout
Access Level Required: SERVICE
This value is only available in Brine mode. It allows
the user to specify the Evaporator Pressure at which a
safety shutdown is initiated. Service Technicians refer
to OptiView Control Center Service Instructions (Form
160.81-M1).
Ice Storage (On / Off)
Access Level Required: SERVICE
When in Brine mode this must be turned ON or OFF
via this toggle and then the Leaving Chilled Liquid
Temperature setpoint is used to automatically activate
or deactivate Ice Storage mode. Service Technicians
refer to OptiView Control Center Service Instructions
(Form 160.81-M1).
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