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to the next programmable value. This value is not
password protected and can be programmed anytime the
PROGRAM key is pressed.
The micro will accept a range of programmable values
between 30 - 115% for the unload point. Keep in mind that
the motor current safety will shut the compressor down
whenever current exceeds 115%. Typically, this setpoint
will be set at 100 - 105%. It is not recommended to
program a value greater than 105%. For maximum
motor protection, programming for 100% is advisable.
NOTE: When programming values from 30 - 99%, it is
required to first key in a "0". Example: 085%.
ANTI-RECYCLE TIME
A N T I
R E C Y C L E
=
6 0 0
S E C S
The ANTI-RECYCLE TIME selection allows the user to
select the compressor anti-recycle time best suited to his
needs. Motor heating is a result of inrush current when the
motor is started. This heat must be dissipated before
another start takes place or motor damage will result. The
anti-recycle timer assures the motor has sufficient time to
cool before it is again restarted. An adjustable timer
allows for the motor cooling required, but gives the user
the ability to extend the timer to cut down on cycling. In
some applications, fast compressor start response is
necessary. In others it is not. These needs should be kept
in mind and the timer should be adjusted for the longest
period of time tolerable. Although 300 seconds is
adequate motor cooling time, longer periods will allow
even more heat dissipation, reduce cycling, and possibly
increase motor life. 600 seconds is recommended.
To program ANTI-RECYCLE TIME, 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 value. This value is not
password protected and can be programmed anytime the
PROGRAM key is pressed.
The micro will accept a range of programmable values
between 300 - 600 seconds for this operating control.
LEAVING WATER TEMP CUT-OUT
L E A V I N G
W A T E R
C U T O U T
=
The LEAVING WATER TEMP CUT-OUT protects the
chiller from an evaporator freeze-up should the chilled
YORK INTERNATIONAL
T I M E
T E M P
3 6 . 0 ° F
liquid temperature drop below the freeze point. This
situation could occur under low flow conditions or if the
Micro Panel Setpoint values are improperly programmed.
Anytime the leaving chilled liquid temperature (water or
glycol) drops below the cut-out point, the chiller will shut
down. The chiller will be re-enabled when temperature
rises more than four degrees above the cut-out.
For chilled water applications (WATER COOLING – SW1
CLOSED), the cut-out is automatically set at 36°F and
cannot be reprogrammed. This covers applications where
leaving water temperatures are not designed to go below
40°F. If the chilled liquid (glycol) temperatures are
required below 40°F (BRINE COOLING – SW1 OPEN),
the cut-out should be programmed 4°F below the Low
Limit Water Temp of the programmed CR (Control Range).
See page 79 on Low Limit Water Temp of Control Range
(CR).
To program the LEAVING WATER TEMP CUT-OUT the
BRINE COOLING (SW1 OPEN) must be selected. Also,
the password protected PROGRAM values must be
accessed as described previously. Key in the desired cut-
out value and press the ENTER key. The new value will
be entered into memory and the display will advance to
the next programmable value.
The micro will accept a range of programmable values
between 08.0 - 36.0°F for this cut-out.
SUCTION PRESSURE CUT-OUT
S U C T I O N
P R E S S U R E
C U T O U T
=
The SUCTION PRESSURE CUT-OUT protects the chiller
from an evaporator freeze-up should the system attempt
to run with a low refrigerant charge. Anytime the suction
pressure drops below the cut-out point for 90 seconds, the
system will shut down.
NOTE: During the first four and a half minutes of
operation, operation of this cut-out will differ from
the operation outlined above. Details are outlined
in the "System Safeties" section.
For chilled water applications, the cut-out should be set at
44 PSIG. If glycol or brine is utilized with leaving water
temperature designs below 40°F, the cut-out should be
adjusted according to concentration. A rule-of-thumb cut-
out design is to drop the cut-out 1 PSIG below 44 PSIG
for every degree of leaving glycol below 40°F. In other
words, 30°F glycol requires a 34 PSIG suction pressure
cut-out.
To program the SUCTION PRESSURE CUT-OUT,
access the password protected values as described
FORM 201.10-NM1
4 4 . 0
P S I G
91
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