FORM 150.60-NM4
YORK INTERNATIONAL
35
“PROGRAM” KEY
PROGRAMMING USER PROGRAMMABLE SAFETIES AND LIMITS
26572A(D)
GENERAL
Pushing the PROGRAM key allows the user to program
“11” system operating limits. These limits include cutout
points for safeties, anti-recycle timer duration, and the
reaction time of the microprocessor to abrupt changes
in the chilled water temperatures.
After the PROGRAM key is pressed, the micro will first
respond by displaying the DISCHARGE CUT-OUT. As
the “11” limits are displayed, they may be reprogrammed
using the “12” ENTRY keys. New values will be pro-
grammed into memory when the ENTER key is pushed.
The ENTER key must also be used to advance the dis-
play the operator views the “10” system operating limits.
Each time the key is pushed, the display will advance to
the next limit.
If the operator attempts to enter an unacceptable value,
the micro will respond with a momentary message indi-
cating the value selected has been ignored. This error
message is shown:
The “11” programmable limit displays are shown and
described below along with the range of values which
the microprocessor will accept for each limit.
THESE
VALUES MUST BE CHECKED AND PROPERLY PRO-
GRAMMED WHEN COMMISSIONING THE CHILLER.
FAILURE TO PROPERLY PROGRAM THESE VALUES
MAY CAUSE DAMAGE TO THE CHILLER OR OPERA-
TION PROBLEMS.
DISCHARGE CUT-OUT
The DISCHARGE CUT-OUT is a microprocessor back-
up for the mechanical high pressure cut-out located in
each refrigerant circuit. Typically chillers with air-cooled
condensers should have the cut-out set at 395 PSIG.
Chillers with water-cooled condensers normally require
the cut-out to be set at 275 PSIG.
NOTE: In some water cooled condenser installations, the
possibility exists for the condenser water pump
or the cooling tower to not be in operation when
the chiller starts. This causes the discharge pres-
sure to rise so rapidly that even though the me-
chanical high pressure cut-out is shutting down
the compressor, the flywheel effect may cause
the pressure to continue to rise causing the relief
valve to open with a subsequent refrigerant loss.
By programming the cut-out at the typical manual
cut-out at 275 PSIG, refrigerant loss due to sys-
tem operation problems will be eliminated.
To program the DISCHARGE CUT-OUT, key in the de-
sired 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.
“PROGRAM”
KEY
O U T
O F
R A N G E
T R Y
A G A I N !
D I S C H A R G E
C U T O U T
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3 9 5
P S I G
