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YORK INTERNATIONAL
78
PROGRAM key
There are six operating parameters under the PRO-
GRAM key that are programmable. These setpoints can
be changed by pressing the PROGRAM key, and then
the ENTER/ADV key to enter
Program Mode
. Continu-
ing to press the ENTER/ADV key will display each op-
erating parameter. While a particular parameter is be-
ing displayed, the UP and DOWN arrow keys can be
used to change the value. After the value is changed,
the ENTER/ADV key must be pressed to enter the data
into memory. Table 29 shows the programmable limits
and default values for each operating parameter.
Following are the displays for the programmable val-
ues in the order they appear:
DISCHARGE PRESSURE CUTOUT is the discharge
pressure at which the system will shutdown as moni-
tored by the
optional
discharge transducer. This is a
software shutdown that acts as a backup for the me-
chanical high pressure switch located in the refrigerant
circuit. The system can restart when the discharge pres-
sure drops 40 PSIG (2.76 BARG) below the cutout point.
If the optional discharge pressure transducer is not in-
stalled, this programmable safety would not apply. It
should be noted that every system has a
mechanical
high pressure cutout that protects against excessive high
discharge pressure regardless of whether or not the op-
tional discharge pressure is installed.
The SUCTION PRESSURE CUTOUT protects the
chiller from an evaporator freeze-up. If the suction pres-
sure drops below the cutout point, the system will shut
down.
There are some exceptions when the
suction pressure is permitted to tem-
porarily drop below the cutout point.
Details are explained under the topic
of System Safeties.
The LOW AMBIENT TEMP CUTOUT allows the user
to select the chiller outside ambient temperature cutout
point. If the ambient falls below this point, the chiller will
shut down. Restart can occur when temperature rises
2°F (1.11°C) above the cutout setpoint.
The LEAVING LIQUID TEMP CUTOUT protects the
chiller from an evaporator freeze-up. Anytime the leav-
ing chilled liquid temperature drops to the cutout point,
the chiller shuts down. Restart will be permitted when
the leaving chilled liquid temperature rises 2°F (1.11°C)
above the cutout setpoint.
When water cooling mode is programmed (Options key),
the value is fixed at 36.0°F (2.22°C) and cannot be
changed. Glycol cooling mode can be programmed to
values listed in Table 28.
The anti-recycle timer message shows the amount of
time left on the respective systems anti-recycle timer.
The programmed ANTI RECYCLE TIME will start to
count down at the start of the systems number one com-
pressor. In effect, this is the minimum time start-to-start
on the respective systems number one compressor.
@ D I SCHARGE PRESSURE
CUTOUT = 395 PSIG
LOW AMB I ENT TEMP
CUTOUT = 2 5 . 0 ° F
LEAVING L IQU ID TEMP
CUTOUT = 3 6 . 0 ° F
SUCT ION PRESSURE
CUTOUT = 4 4 . 0 PS I G
ANT I RECYCLE T IME
= 600 SEC
Unit Controls