
FORM 201.10-NM4
67
YORK INTERNATIONAL
1. INTRODUCTION AND PHYSICAL DESCRIPTION
1.1 GENERAL
The YORK
Millennium
Screw Chiller Control Panel is a
microprocessor-based control system fitted to YDAS
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 English (Imperial)
units or S.I. (Metric) units. For clarity this manual uses
English (Imperial) units only. Conversion tables are pro-
vided at the back of this manual.
A master ON/OFF rocker switch is provided on the chiller
control panel to activate or deactivate the complete
chiller while switches to activate or deactivate individual
refrigerant systems are provided on the Microproces-
sor Board(s).
External interface is available for control of the chiller
via a YORK ISN system or YORK Remote Control Cen-
ter. In addition, EMS/BAS system connections are pro-
vided for remote cycling, current limiting, remote tem-
perature setpoint reset and alarm annunciation.
YCAS chillers each have a single split circuit evaporator
serving either 2 or 3 independent refrigerant systems.
YCAS 2 System chillers are configured as a single, self-
contained section with a single control panel controlling
the 2 refrigerant systems. YCAS 3 System chillers are
divided into a Master section containing Systems 1 & 2
and a
Subordinate
section containing System 3.
YDAS chillers have two split circuit evaporators each
serving 2 independent refrigerant systems. YDAS chill-
ers are divided into a Master section containing Sys-
tems 1 & 2 together with dual circuit evaporator 1, and
a
Subordinate
section containing Systems 3 & 4
together with
dual circuit evaporator 2.
Master and
Subordinate
sections on YCAS (3
compressor)
and YDAS (4 compressor) chillers each
have their own
control panel complete with
microprocessor board to
control their associated
systems. Communications be-tween panels is via a
2-wire RS-485 interface. The
master section control
panel only is fitted with a Key-pad, Display and
Chiller Switch as described below.
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 set-
points, and initiate system commands. Keys are grouped
and color-coded for clarity and ease of use.
The 40-character Liquid Crystal Display (2 lines of 20 char-
acters) is used for displaying system parameters and op-
erator messages. The display has a lighted background
for night viewing as well as a special feature which inten-
sifies the display for viewing in direct sunlight.
28164(B)A
Содержание Millennium YDAS 410
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