98
YORK INTERNATIONAL
1. INTRODUCTION & PHYSICAL DESCRIPTION
1.1 GENERAL
The YORK Millennium Screw Chiller Control Panel is
a microprocessor based control system fitted to YCAS
liquid chillers. It is capable of multi-refrigerant system
control to maintain chilled liquid temperature within pro-
grammed limits and to provide safety control of the
chiller. The microprocessor monitors leaving chilled liq-
uid temperature 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 S.I. (Metric) units
or English (Imperial) units (Section 8.1). Conversion
tables are provided at the back of this manual.
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-
croprocessor Board(s).
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-
perature setpoint reset and alarm annunciation.
YCAS chillers each have a single split circuit evapora-
tor serving either 2, 3, or 4 independent refrigerant sys-
tems. YCAS 2 and 3-system chillers are configured as
a single self contained section with a single control panel
controlling the two refrigerant systems. YCAS 4-sys-
tem chillers are divided into 2 sections.
1.2 KEYPAD & DISPLAY
An operator keypad allows complete control of the chiller
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
characters) is used for displaying system parameters
and operator messages. The display has a lighted back-
ground for night viewing as well as a special feature
which intensifies the display for viewing in direct
sunlight.
Displays will be updated every two seconds by the mi-
croprocessor.
1.3 UNIT (CHILLER) ON / OFF SWITCH
A master UNIT (Chiller) ON / OFF switch is located
just below the keypad. This switch allows the operator
to turn the entire chiller OFF, if desired. The switch
must be placed in the ON position for the chiller to op-
erate. Any time the switch is in the OFF position, a
Status message indication will be displayed. See Page
93 for the location of this switch.
1.4 MICROPROCESSOR BOARD
The Microprocessor Board(s) controls and makes de-
cisions for the chiller. Information inputs from trans-
29023A
Micropanel
Summary of Contents for MILLENNIUM YCAS
Page 53: ...53 YORK INTERNATIONAL FORM 201 18 NM2 WIRING DIAGRAM ACROSS THE LINE START 7...
Page 54: ...54 YORK INTERNATIONAL FIG 12 CONTINUED ELEMENTARY DIAGRAM Technical Data...
Page 59: ...59 YORK INTERNATIONAL FORM 201 18 NM2 WIRING DIAGRAM WYE DELTA START LD03229 FIG 15 CONT D 7...
Page 60: ...60 YORK INTERNATIONAL FIG 15 CONTINUED ELEMENTARY DIAGRAM Technical Data...
Page 62: ...62 YORK INTERNATIONAL FIG 16 POWER PANEL FRONT INSIDE VIEW WYE DELTA START Technical Data...
Page 68: ...68 YORK INTERNATIONAL FIG 24 DETAIL B Technical Data...
