Specifications

10 YORK INTERNATIONAL
PULL DOWN DEMAND - This function is used to pro-
vide energy savings following the chiller start-up. This
key displays a programmable motor current limit and
programmable period of time. Operation is as follows:
Whenever the system starts, the Pull Down Demand
Limit is maintained for the programmed time, then the
current limit control returns to % Current Limit setpoint.
The maximum permitted motor current is in terms of %
FLA. The duration of time that the current is limited is in
terms of minutes (to a maximum of 255). If not pro-
grammed, the default value is 100% FLA for 00 minutes
(See “Programming System Setpoints”, page 13). Thus,
no pull down demand limit is imposed following system
start, and the % Current Limit setpoint is used.
CLOCK - This key displays the day of the week, time of
day and calendar date. If not programmed, the default
value is
SUNDAY 12:00 AM 1/1/89
(See “Programming System Setpoints”, page 13.)
DAILY SCHEDULE - This key displays the programmed
daily start and stop times, from Sunday through Satur-
day plus Holiday. If desired, the Control Center can be
programmed to automatically start and stop the chiller
as desired. This schedule will repeat on a 7-day calen-
dar basis. If the Daily Schedule is not programmed, the
default value is 00:00 AM start and stop times tor all
days of the week and the holiday. (Note that the system
will not automatically start and stop on a daily basis with
these default values because 00:00 is an “Impossible”
time for the Micro Board; see “Programming System
Setpoints”, page 13). Finally, one or more days in the
week can be designated as a holiday (See description
under “HOLIDAY” setpoint) and the Control Center can
be programmed (using “DAILY SCHEDULE” setpoint)
to automatically start and stop the chiller on those days
so designated. The operator can override the time clock
at any time using the “COMPRESSOR” switch.
Note that if only a start time is entered for a particular
day, the compressor will not automatically stop until a
scheduled stop time is encountered on a subsequent
day.
HOLIDAY - This key indicates which days in the upcom-
ing week are holidays. On those designated days, the
chiller will automatically start and stop via the holiday
start and stop times programmed in the “DAILY SCHED-
ULE” setpoint. It will do this one time only and the follow-
ing week will revert to the normal daily schedule for that
day.
REMOTE/RESET TEMP RANGE - This key displays the
maximum offset of remote LCWT setpoint reset. This
offset is either 10° or 20°F as programmed. When in
the remote mode, this value is added to the operator
programmed chilled liquid temp setpoint and the sum
equals the temperature range in which the LCWT can
be reset. For example, if the operator programmed chilled
liquid temp setpoint is programmed with a value of 10°F,
then the chilled liquid temp setpoint can be remotely re-
set over a range of 46°F to 56°F (46 + 10 = 56). If not
programmed, the default value for this parameter is 20°F.
For additional information on remote LCWT reset, refer
to Form 160.46-PA4.1.
NOTE: If an Energy Management System is interfaced
to the Control Center for the purpose of remote
LCWT setpoint reset, then the operator pro-
grammed REMOTE RESET TEMP RANGE
value determines the maximum value of tem-
perature reset controlled by the Energy Man-
agement System.
DATA LOGGER - This key is used when an optional
printer is connected to the MicroComputer Control Cen-
ter. Refer to Form 160.48-NO1.2 for operation instruc-
tions.
SSS MOTOR CURRENT/VOLTS - This key is used on
Solid State Starter applications only. Although this is a
display key, it is also used to program the applicable AC
power line voltage range (200-208 VAC, 220-240 VAC,
380 VAC, 400 VAC, 415 VAC, 440-480 VAC, 550-600
VAC). The MicroComputer Control Center uses this entry
to determine the undervoltage-shutdown threshold. For
each line voltage category, there are two shutdown
thresholds - a minimum line voltage level required to
start the compressor and a minimum level required af-
ter the Control Center is in “RUN” mode. In “ RUN” mode,
the voltage must be less than the run threshold for 20
continuous seconds in order to initiate a shutdown. When
the chiller shuts down,
MON 10:00 AM LOW LINE VOLTAGE
is displayed. This undervoltage protection can be dis-
abled. The selectable supply voltage ranges and their
shutdown thresholds are as follows:
supply voltage range TO START RUN
200-208 VAC 174 VAC 160 VAC
200-240 200 185
380 331 305
400 349 320
415 362 335
440-480 400 370
550-600 502 460
Supply voltage range disabled 0 None
If Control Center is equipped with version 3.E and later
EPROM, an overvoltage shutdown threshold is also
checked. If the line voltage exceeds the overvoltage
threshold for 20 continuous seconds, the chiller shuts
down,