24 YORK INTERNATIONAL
SINGLE CIRCUIT UNITS
Closure slightly longer than 21 seconds will be treated
as 21 seconds.
The contact closure corresponds to a positive offset (rise)
from the setpoint on the panel. 1 sec. = +0 offset and 21
sec. = +40°F (4.4°C) or offset = 2 (time closed - 1 sec.).
For example: A setpoint of 25°F (–3.9°C) on the panel
and a contact closure of 8.5 sec. will result in an offset
of 15°F (8.33°C). This raises the RWT setpoint to 40°F
(4.4°C). Note: Metric Offset = 1.11 (time closed - 1 sec.).
To maintain the remote setpoint above the EMS Pulse
Width Modulation input (terminals 75 & 76) on the Digi-
tal Input Board must be refreshed every 30 minutes or
less (20 minutes is recommended). In otherwords, to
maintain the 40°F (4.4°C) RWT setpoint, the contacts
between terminals 75 & 76 must be closed for a period
of 8.5 seconds every 20 minutes. If this is not refreshed
SYSTEM “ON/OFF” SWITCH
This switch allows the operator to manually turn the unit
on or off. To operate the unit, the switch must be in the
“ON” position.
FIG. 15 – START/STOP CONTROLS
UNIT START-UP SEQUENCE
A simplified start-up sequence is provided on the con-
trol panel to aid the operator in running the chiller.
START/STOP CONTROLS
Before attempting start-up, the temperature and Start/Stop Controls should be properly set and understood.
at least every 30 minutes, the Micro Logic Board will
take this as a signal to change the RWT setpoint back
to the original setpoint of 25°F (–3.9°C) on the Control
Panel. See EMS/BAS Option in OPTIONS section for
more information.
ANNUNCIATION ALARM CONTACTS (OPTIONAL)
YORK can supply an alarm kit whose contacts will tran-
sition to function as a warning if unit malfunction occurs.
A 115VAC or 28VDC volt external alarm circuit (by oth-
ers) must be wired into the YORK supplied alarm cir-
cuit. If the alarm circuit is applied to chillers used for
critical duty (such as process duty, or cooling other criti-
cal equipment) and the alarm circuit should fail to func-
tion, YORK will not be liable for damages. See ALARM
Option in “OPTIONS” section for more information.
LD01854
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