York YK-EP Operation And Maintenance Manual page 32

Table 14: Programmable
Button Access level
Local Leaving
Chilled Liquid
Operator
Temperature
– Setpoint
Leaving
Chilled Liquid
Temperature
Operator
Cycling
Offset –
Shutdown
Leaving
Chilled Liquid
Temperature
Operator
Cycling
Offset –
Restart
Note: * The offset being used is displayed as Effective Offset in the upper right area of the
display. Usually, the Offset used is the same as the value programmed for the Shutdown
Setpoint. However, the Offset being used will automatically change based on the values
programmed for the Leaving Chilled Liquid Temperature Setpoint and the Shutdown Setpoint,
to prevent the Leaving Chilled Liquid Temperature from going below the minimum allowed
value: 36°F (water), 34°F (water with smart freeze enabled) or 6°F (brine). For example, if the
Leaving Chilled Liquid Temperature Setpoint is set to 45°F (water) and the Shutdown Setpoint
is set to 4°F, the Effective Offset is displayed as 4°F. If the leaving setpoint is lowered to 38°F,
the Effective Offset will change to 2°F. If the leaving chilled setpoint is raised back to 45°F, the
Effective Offset will revert back to the Shutdown Setpoint.
32
Description
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 10.0°F
to 70.0°F (brine). If Smart Freeze is enabled, the range is 36.0°F to
70.0°F (water). 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 the operator programmed
BASE Leaving Chilled Liquid Temperature Setpoint. This offset may
be defined as 10, 20, 30, or 40°F above the BASE Setpoint (refer
to the Leaving Chilled Liquid Temperature Setpoints – Setpoint
description). Additionally, an E-Link or SC-Equip Gateway (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 applied
to the locally programmed BASE Setpoint value, but rather is the
setpoint value itself.
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 cutout of 36°F (water),
34°F (water with Smart Freeze enabled) or 6°F (brine). Anytime
the Leaving Chilled Liquid Temperature Setpoint is increased, the
setpoint is increased at a rate of 0.2°F per second to allow the chiller
time to unload*.
This value allows the user to specify the Leaving Chilled Liquid
Temperature at which the chiller will restart after 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 restart 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.
YK-EP Style B Centrifugal Chiller