FORM 150.24-NM27
YORK INTERNATIONAL
51
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 YCR chillers should
have the cut-out set at 360 PSIG. Chillers with water-
cooled condensers normally require the cut-out to be
set at 270 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 dis-
charge pressure to rise so rapidly that even
though the mechanical high pressure cut-out is
shutting down the compressor, the flywheel ef-
fect may cause the pressure to continue to rise
causing the relief valve to open with a subse-
quent refrigerant loss. By programming the
cut-out at slightly below typical manual cut-out
of 270 PSIG, refrigerant loss due to system op-
eration 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
=
3 9 5
P S I G
Summary of Contents for YCRJ45E00
Page 29: ...FORM 150 24 NM27 YORK INTERNATIONAL 29 CONTROL CIRCUIT With I O Expansion Board LD02106 ...
Page 30: ...30 YORK INTERNATIONAL FIG 9 SYSTEM WIRING ...
Page 31: ...FORM 150 24 NM27 YORK INTERNATIONAL 31 LD02678 ...
Page 35: ...FORM 150 24 NM27 YORK INTERNATIONAL 35 LD02679 ...
Page 36: ...36 YORK INTERNATIONAL MICROPANEL CONNECTION DIAGRAM With I O Expansion Board LD02107 ...
Page 37: ...FORM 150 24 NM27 YORK INTERNATIONAL 37 LD02108 ...
