Anticipation Control Status Messages - York MILLENNIUM YCAS Installation Operation & Maintenance

Micropanel
The U13 RTC chip should be replaced as soon as pos-
sible with Part # 031-00955-000. Otherwise, the chiller
will shutdown and lose all programmed points, and re-
quire a MANUAL OVERRIDE restart, if a power fail-
ure occurs.
Pump Down:
S Y S 1 P U M P I N G
S Y S 2 P U M P I N G
This message indicates that both refrigerant systems
are in a pumpdown cycle. Pumpdown display messages
occur on shutdowns where the cooling load has been
met, or when a system switch is turned OFF. Note that
only one compressor could be pumping down, as shown
in the following display:
S Y S 1 P U M P I N G
S Y S 2 C O M P
See Section 1.18 for details of pumpdown control.
Incorrect Refrigerant Warning:
R E P R O G R A M
R E F R I G E R A N T
The Incorrect Refrigerant Warning will occur if the DIP
Switch setting for refrigerant type and the type pro-
grammed into the micro "at the factory" are not the
same. This message will be displayed until the non-pro-
grammable "factory" programmed refrigerant type and
DIP Switch setting agree.
Power Failure Warning:
The Power Failure Warning will only be displayed on
"power restoration" after a "power loss", if manual re-
start on power failure is selected under the PROGRAM
key (Page 129). If manual restart on power failure has
been selected, the following warning message is dis-
played indefinitely on power restoration and the chiller
will not run until the UNIT Switch is cycled OFF-and-
on to restart the unit. This safety is available for users
who desire a chiller lock-out on power failure. NOTE:
This is typically not a desirable feature.
! ! P O W E R
C Y C L E U N I T
When this message appears, the chiller will not run and
the Unit Switch must be cycled OFF and ON to start
the unit.
110
D O W N
D O W N
D O W N
R U N N I N G
T Y P E O F
T O R U N
F A I L U R E ! !
S W I T C H
2.4 ANTICIPATION CONTROL STATUS
MESSAGES
Anticipation controls are built into the software to pre-
vent safety shutdowns by automatically overriding the
temperature controls, if system conditions approach
safety thresholds. This avoids total loss of cooling re-
sulting from a lockout by a safety control.
Anticipation controls monitor discharge pressure, motor
current and suction temperature for each compressor
and if maximum limits are approached, the slide valve
loading of the respective compressor will be reduced to
avoid exceeding the limit.
Displays of anticipation safety control messages and
their meanings are as follows:
Discharge Pressure Limiting:
S Y S # D S C H
S Y S # D S C H
Discharge Pressure Limiting takes effect when com-
pressor discharge pressure nears the point at which the
high pressure cutout would shut the system down. When
the above message appears, discharge pressure has
exceeded the programmable threshold and the compres-
sor is being unloaded in an effort to prevent shutdown
on the high pressure cutout. The operation of this safety
is important if condenser coils become dirty, if there is a
problem with the condenser fan operation, or if extreme
ambient or load conditions occur (see Section 8.2 / High
Discharge Pressure Unload Point [page 129] for more
details).
Compressor Motor Current Limiting:
S Y S # C U R R
S Y S # C U R R
The Motor Current Limiting message indicates that a
compressor motor current has reached a programmable,
Bas, or remote limit and the system is being unloaded to
assure that motor current does not become excessively
high causing a fault (see also Section 8.2 / High Motor
Current Unload Point, page 138; Section 3.5, Motor Cur-
rent Key, page 117; Section 1.10, page 102).
Suction Temperature Limiting:
S Y S # S U C T
S Y S # S U C T
L I M I T I N G
L I M I T I N G
L I M I T I N G
L I M I T I N G
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YORK INTERNATIONAL