York YK Style H Operation Manual page 29

FORM 160.76-O2
issue date: 6/15/2015
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 Off-
set 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.
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 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 program-
mable 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.
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.
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
Sensitivity
Access Level Required: SERVICE
This value allows the user to adjust the sensitivity of
the Leaving Chilled Liquid Temperature control.
Smart Freeze (Off / On)
Access Level Required: SERVICE
This value is only available if the chiller is not in Brine
mode. It allows the user to enable the Smart Freeze
Point Operation which allows the chiller to run closer
to the freeze point without shutting down.
Refrigerant (Enabled / Disabled)
Access Level Required: SERVICE
When an Evaporator Refrigerant Sensor has been in-
stalled it must be enabled via this toggle before the
system will utilize the new, enhanced resolution input.
NAVIGATION
Home
Access Level Required: VIEW
Returns user to HOME Screen.
Heat Pump
Access Level Required: VIEW
Moves to a sub screen allowing programming and
viewing of the Heat Pump Setpoints and parameters.
Only appears when Heat Pump is enabled on the SET-
UP Screen.
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