YORK INTERNATIONAL
86
FORM 150.62-NM7 (103)
to change the value. After the value is changed, the
ENTER/ADV key must be pressed to enter the data into
memory. Table 20 shows the programmable limits and
default values for each operating parameter.
Following are the displays for the programmable values
in the order they appear:
DISCHARGE PRES SURE CUT OUT is the dis charge
pres sure at which the system will shut down as mon i tored
by the optional dis charge trans duc er. This is a software
shutdown that acts as a back up for the me chan i cal high
pressure switch located in the re frig er ant circuit. The
system can restart when the dis charge pres sure drops
40 PSIG (2.76 BARG) be low the cutout point.
If the op tion al dis charge pres sure trans duc er is not
in stalled, this pro gram ma ble safety would not apply. It
should be noted that every system has a me chan i cal
high pressure cutout that protects against ex ces sive
high discharge pressure regardless of wheth er or not
the op tion al dis charge pressure is in stalled.
The SUCTION PRESSURE CUTOUT pro tects the chill er
from an evaporator freeze-up. If the suction pres sure drops
below the cutout point, the sys tem will shut down.
There are some exceptions when the
suction pres sure is permitted to tem-
po rari ly drop be low the cut out point.
De tails are ex plained un der the top ic
of SYS TEM SAFE TIES.
The LOW AMBIENT TEMP CUTOUT al lows the user
to select the chiller outside ambient tem per a ture cut out
point. If the ambient falls below this point, the chiller will
shut down. Restart can occur when tem per a ture rises
2°F (1.11°C) above the cutout setpoint.
The LEAVING LIQUID TEMP CUTOUT protects the
chill er from an evaporator freeze-up. Anytime the leav-
ing chilled liquid tem per a ture drops to the cutout point,
the chiller shuts down. Re start will be per mit ted 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 fi xed at 36.0°F (2.22°C) and can not
be changed. Glycol cooling mode can be pro grammed
to values listed in Table 20.
The programmable anti-recycle timer assures that sys-
tems do not cycle. This timer is programmable under the
PROGRAM key between 300 - 600 seconds. When ev er
possible, to reduce cycling and motor heating, the anti-
recycle timer should be adjusted as high as pos si ble.
The programmable anti-recycle timer starts the timer
when the fi rst compressor in a system starts. The timer
begins to count down. If all the compressors in the cir-
cuit cycle off, a compressor within the circuit will not be
permitted to start until the anti-recycle timer has timed
out. If the lead system has run for less than 5 minutes,
3 times in a row, the anti-recycle timer will be extended
to 10 minutes maximum.
The Fan Control On-Pressure is the pro grammed pres sure
value that is used to stage the con dens er fans on, in rela-
tion to discharge pres sure. Refer to Condenser Fan Control
in the UNIT OP ER A TION sec tion and Ta bles 26 - 31.
The microprocessor will not allow pro-
gram ming the “FAN CONTROL ON
PRES SURE” minus the “FAN CON-
TROL DIF FER EN TIAL OFF PRES-
SURE” be low 160PSIG. This assures
dis charge pres sure does not drop too
low.
The Fan Differential Off Pressure is the pro grammed
dif fer en tial pressure value that is used to stage the con-
dens er fans off, in re la tion to dis charge pres sure. Re fer
to Con dens er Fan Con trol in the UNIT OP ER A TION
sec tion and Ta bles 26 - 31.
The microprocessor will not allow pro gram -
ming the “FAN CONTROL ON PRES-
SURE” minus the “FAN CON TROL
DIF FER EN TIAL OFF PRES SURE”
be low 160 PSIG. This assures dis charge
pres sure does not drop too low.
L O W A M B I E N T T E M P
C U T O U T = 2 5 . 0 ° F
L E A V I N G L I Q U I D T E M P
C U T O U T = 3 6 . 0 ° F
S U C T I O N P R E S S U R E
C U T O U T = 4 4 . 0 P S I G
A N T I R E C Y C L E T I M E R
= 6 0 0 S E C
F A N C O N T R O L O N
P R E S S U R E = X X X P S I G
FAN D I F F E R E N T I A L O F F
P R E S S U R E = X X X P S I G
d D I S C H A R G E P R E S S U R E
C U T O U T = 3 9 5 P S I G
Unit Controls
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