York MILLENNIUM YCAL0043SC, Manual

Page: 56 / 133

YORK INTERNATIONAL
56
When this message appears, suction pressure limiting
is in effect. Suction Pressure Limiting is only available
on units that have the suction pressure transducer in-
stalled. If a low pressure switch is installed instead, suc-
tion pressure limiting will not function.
The suction pressure limit is a control point that limits
the loading of a system when the suction pressure drops
to within 15% above the suction pressure cutout. On a
standard system programmed for 44 PSIG/3.0 Bar suc-
tion pressure cutout, the micro would inhibit loading of
the affected system with the suction pressure less than
or equal to 1.15 * 44 PSIG/3.0 Bar = 50 PSIG/3.5 Bar.
The system will be allowed to load after 60 seconds
and after the suction pressure rises above the suction
pressure limit point.
This message indicates that load limiting is in effect and
the percentage of the limiting in effect. This limiting could
be due to the load limit/pwm input or an ISN controller
could be sending a load limit command.
If MANUAL OVERRIDE mode is selected, the STATUS
display will display this message. This will indicate that
the Daily Schedule is being ignored and the chiller will
start-up when chilled liquid temperature allows, Remote
Contacts, UNIT switch and SYSTEM switches permit-
ting. This is a priority message and cannot be overrid-
den by anti-recycle messages, fault messages, etc. when
in the STATUS display mode. Therefore, do not expect
to see any other STATUS messages when in the
MANUAL OVERRIDE mode. MANUAL OVERRIDE is to
only be used in emergencies or for servicing. Manual
override mode automatically disables itself after 30 min-
utes.
The PUMPING DOWN message indicates that a com-
pressor in the respective system is presently in the pro-
cess of pumping the system down. When pumpdown is
initiated, the liquid line solenoid will close and a com-
pressor will continue to run. When the suction pressure
decreases to the suction pressure cutout setpoint, the
compressor will cycle off. If pump down cannot be
achieved three minutes after the liquid line solenoid
closes, the compressor will cycle off.
FAULT STATUS MESSAGES
Safeties are divided into two categories - system safe-
ties and unit safeties. System safeties are faults that
cause the individual system to be shut down. Unit safe-
ties are faults that cause all running compressors to be
shut down. Following are display messages and expla-
nations.
SYSTEM SAFETIES
System safeties are faults that cause individual systems
to be shut down if a safety threshold is exceeded for 3
seconds. They are auto reset faults in that the system
will be allowed to restart automatically after the fault con-
dition is no longer present. However, if 3 faults on the
same system occur within 90 minutes, that system will
be locked out on the last fault. This condition is then a
manual reset. The system switch (under OPTIONS key)
must be turned off and then back on to clear the lockout
fault.
S Y S 1 S U C T L I M I T I N G
S Y S 2 S U C T L I M I T I N G
S Y S 1 L O A D L I M I T X X %
S Y S 2 L O A D L I M I T X X %
M A N U A L
O V E R R I D E
S Y S 1 P U M P I N G D O W N
S Y S 2 P U M P I N G D O W N
Unit Controls