York YCAS0130 - Manual (Page 123)

123 YORK INTERNATIONAL
FORM 201.19-NM1 (204)
1. INTRODUCTION & PHYSICAL DESCRIPTION
29023A
1.1 GENERAL
The YORK Screw Chiller Control Panel is a mi cro pro -
ces sor based control system fi tted to YCAS liq uid chill-
ers. It is capable of multi-re frig er ant system con trol to
maintain chilled liquid tem per a ture within pro grammed
limits and to provide safety control of the chill er. The
microprocessor monitors leav ing chilled liq uid tempera-
ture deviation from setpoint and the rate of change of this
temperature to start, stop, load and un load compressors
as required.
User interface is via a touch keypad and a liquid crystal
display allowing access to operating and programmed
data. Information can be displayed in English (Im pe ri al)
units or SI (Metric) units (Section 8.1). Con ver sion
ta bles are provided at the back of this man u al.
A master ON/OFF rocker switch is provided on the
chiller control panel to activate or deactivate the com-
plete chiller, while switches to activate or deactivate
individual refrigerant systems are provided on the Mi-
cro pro ces sor Board.
External interface is available for control of the chiller
via a YORK ISN System or YORK Remote Control
Center. In addition, EMS/BAS System connections are
provided for remote cycling, current limiting, remote
tem per a ture setpoint reset and alarm annunciation.
YCAS chillers each have a single split circuit evap o -
ra tor serving 2 independent refrigerant sys tems. YCAS 2
system chillers are confi gured as a sin gle self con tained
section with a single control pan el con trol ling the two
refrigerant systems.
1.2 KEYPAD & DISPLAY
An operator keypad allows complete control of the
chill er from a central location. The keypad offers a
multitude of commands available to access displays,
program setpoints, and initiate system commands.
Keys are grouped and color coded for clarity and ease
of use.
A 40 Character Liquid Crystal Display (2 lines of 20
char ac ters) is used for displaying system parameters
and op er a tor messages. The display has a lighted back-
ground for night viewing as well as a special feature
which in ten si fi es the display for viewing in direct
sunlight.
Displays will be updated every two seconds by the
mi cro pro ces sor.
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