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ENERGY MANAGEMENTS SYSTEMS (CONT'D)
3. The Graphic Control Center has a programmable
time clock function as a standard feature with holi-
day capability. This offers one preset automatic
Start-Stop per day on a seven day calendar basis
with the ability to program a single additional holi-
day start and stop time up to a week in advance.
Chilled water pump control contacts (see Note 13)
are also provided, allowing for efficient automatic
operation of the chilled water pump to reduce en-
ergy. Two chilled water pump operating modes are
available via the CHW PUMP programming dip
switch (position 8 of SW1) on the Micro Board.
With the switch in the OFF position, the chilled
water pump operates for 30 seconds prior to chiller
start, during chiller operation, coastdown, and
LWT cycling shutdowns. With the switch in the
ON position, the chilled water pump operates as
above plus it operates during MULTI-UNIT and
REMOTE/LOCAL cycling shutdowns.
4. Reduce the compressor-motor kW input (and thus
amps), by raising the leaving chilled liquid
temperature through remote temperature control
setpoint in the "remote" operating mode. When
remote temperature reset is accomplished by sup-
plying a 1 to 11 second pulse-width modulated sig-
nal, refer to Fig. 20. Through use of the remote
temperature control analog input on the Micro
Board, the leaving chilled liquid temperature may
be reset via a 0 to 20 or 4 to 20mA D.C. current
signal, a 0 to 10 or 2 to 10 volt D.C. signal.
5. Current limiting of demand during pulldown may
External wiring, unless specified as
an optional connection in the
manufacturer's product literature, is
not to be connected inside this cabi-
net. Furthermore, auxiliary devices
such as relays, switches, transducers and controls
may not be installed inside this enclosure. All
wiring must be in accordance with YORK's pub-
2
be accomplished by using the standard
PULLDOWN DEMAND LIMIT function pro-
vided in the Graphic Control Center. The
"Pulldown Demand Limit" key can be programmed
to limit compressor motor current from 30 to 100
percent of full load amperes, for 1 to 255 minutes
following each compressor start. For more details
refer to Graphic Control Center Instructions, Form
160.55-O1.
6. Controlling the maximum allowable compressor
motor amps from 30 to 100% through remote cur-
rent limit setpoint. Refer to Fig. 17 when the re-
mote current limit is accomplished by supplying a 1
to 11 second pulse-width modulated signal in the
"remote" operating mode. A jumper configurable
analog input is available for remote current limit
setpoint via a 0 to 20 or 4 to 20mA D.C. current
signal, a 0 to 10 or 2 to 10 volt D.C. signal.
7. The YORK ISN System may be interfaced with
the chiller Graphic Control Center to provide uni-
fied chiller plant system control. The ISN System
directly communicates with the Graphic Control
Center via the ISN GPIC card which may be in-
stalled in the Control Center. All temperatures, pres-
sures, safety alarms and cycling information known
to the Graphic Control Center are then available to
the ISN System for integrated chiller plant control,
data logging, and local and remote operator dis-
plays. The ISN GPIC card also allows the ISN to
start, stop, and reset the chiller's leaving chilled
water and current limit setpoints.
lished specifications and must be performed only
by qualified personnel. YORK will not be respon-
sible for damages resulting from improper con-
nection to these controls or application of im-
proper control signals. Failure to follow this
warning will void the manufacturer's warranty
and may cause serious damage to property or in-
jury to persons.
YORK INTERNATIONAL
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