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YORK INTERNATIONAL
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NOTE: It is required to first key in a “0” when program-
ming this cut-out (Example: 0395 PSIG).
More details on this safety are outlined in the SYSTEM
SAFETIES section.
OUTSIDE AIR TMP LOW CUT-OUT
The OUTSIDE AIR TMP LOW CUT-OUT allows the
user to select the chiller low ambient temperature cut-
out point. If the ambient falls below this point the chiller
will shut down. Restart can occur, if demand allows,
when temperature rises above the cut-out. This only
applies to outdoor air-cooled chillers.
For normal ambient applications, the cut-out is set at
25.0°F and is NOT programmable. However, some us-
ers may set the cut-out higher to shut down the chiller
and take advantage of other less costly cooling sources.
In this case, S1 Dip Switch #2 on the Micro Logic Board
must be in the CLOSED position for Low Ambient Con-
trol to allow programming the cut-out above 25°F.
Low ambient applications in ambients less than 25.0°F
require a low ambient kit to be installed. Otherwise nui-
sance low pressure and low motor current trips will re-
sult. If a low ambient kit is installed, the cut-out may be
lowered as needed below 25°F. If operation is occa-
sionally needed below 0°F, the cut-out should be set at
00.0°F. This will allow operation at any temperatures
since the micro is only able to recognize temperatures
above 1°F, regardless of the display.
NOTE: Operation below 0°F may cause other types of
nuisance safety shutdowns, but occasional
shutdowns can usually be tolerated since the
need for sustained operation at these tempera-
tures is unlikely and temperatures rarely stabi-
lize for any length of time below 0°F.
The micro will accept a range of programmable values
between 00.0° - 50.0°F for this cut-out, if S1 Dip Switch
#2 on the Micro Logic Board is in the CLOSED position.
In the OPEN position, a fixed 25°F cut-out is recognized.
To program the OUTSIDE AIR TMP LOW CUT-OUT,
key in the desired value and press the ENTER key. The
new value will be entered into memory and the display
will advance to the next user programmable limit.
OUTSIDE AIR TMP HIGH CUT-OUT
The OUTSIDE AIR TMP HIGH CUT-OUT is selectable to
establish the high ambient cut-out point. If the ambient
rises above this point, the chiller will shut down. Restart
can occur when temperature drops below the cut-out.
This only applies to outdoor air-cooled chillers.
This cut-out is normally set at 130.0°F to allow opera-
tion to the absolute maximum temperature capability of
the electro-mechanical components.
To program the OUTSIDE AIR TMP HIGH CUT-OUT,
key in the desired value and press the ENTER key. The
new value will be entered into memory and the display
will advance to the next user programmable limit.
The micro will accept a range of programmable values
between 100.0° - 130.0°F for this cut-out.
DISCHARGE PRESSURE UNLOAD
The DISCHARGE PRESSURE UNLOAD point is a pro-
grammable limit to keep the system from faulting on
the high discharge pressure cut-out should a system
problem or chiller problem occur. A typical problem
would be if the cooling tower would become dirty on a
water-cooled system. Pressure would rise and eventu-
ally cause the chiller to fault causing total loss of cool-
ing. By unloading the compressors at high discharge
pressures, the chiller is allowed to continue to run auto-
matically at reduced capacity until the dirty cooling tower
can be attended to.
When the unload point is reached, the micro will auto-
matically totally unload the affected compressor. Typi-
cal maximum programmed limits would be 375 PSIG
for air-cooled chillers with 395 or 405 PSIG high pres-
sure cut-outs and 255 PSIG for water-cooled chillers
with 275 PSIG cut-outs.
Reloading will occur when the discharge pressure drops
to 60 PSIG below the programmed unload pressure and
will increment one stage at a time as dictated by the
loading timers.
To program the DISCHARGE PRESSURE UNLOAD,
key in the desired value and press the ENTER key. The
new value will be entered into memory and the display
will advance to the next user programmable limit.
The micro will accept a range of programmable values
between 200-390 PSIG for the unload point. For this
feature to be functional, the Discharge Pressure Read-
out Option must be installed.
NOTE: It is required to first key in a “0” when program-
ming this cut-out (Example: 0375 PSIG).
O U T S I D E A I R T M P L O W
C U T O U T = 2 5 . 0 F
D I S C H A R G E P R E S S U R E
U N L O A D = 3 6 0 P S I G
O U T S I D E A I R T M P H I G H
C U T O U T = 1 3 0 . 0 F