York YCAZ33BA3, Руководство пользователя, Страница: 34 / 88

YORK INTERNATIONAL
34
GENERAL
Pushing the PROGRAM key allows the user to pro-
gram “11” system operating limits. These limits include
cut-out 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 repro-
grammed using the “12” ENTRY keys. New values will
be programmed into memory when the ENTER key is
pushed. The ENTER key must also be used to advance
the display as the operator views the “10” system op-
erating 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 in-
dicating the value selected has been ignored. This er-
ror 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 opera-
tion when the chiller starts. This causes the dis-
charge pressure to rise so rapidly that even
though the mechanical 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 sub-
sequent refrigerant loss. By programming the
cut-out at slightly below the typical manual cut-
out of 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 ad-
vance to the next user programmable limit.
The micro will accept a range of programmable values
between 200-399 PSIG for this cut-out. For this cut-out
to be functional, the Discharge Pressure Read-out Op-
tion must be installed.
26572A
“PROGRAM” KEY
PROGRAMMING USER PROGRAMMABLE SAFETIES & LIMITS
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
= 3 9 5 P S I G
“PROGRAM”
KEY