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24 YORK INTERNATIONAL
at 265 PSIG (R-22); 180 PSIG (R-134a). When the con-
denser pressure falls to 245 PSIG (R-22); 160 PSIG
(R-134a), the vanes will be permitted to open.
SYSTEM RUN – PRESSURE STATUS
Displayed when the chiller is running. It instructs the
operator to press the STATUS key, whereupon one of
the following messages will be displayed:
•
WARNING: COND OR EVAP TRANSDUCER ERROR
Indicates a probable condenser or evaporator trans-
ducer problem, because the output is unreasonable.
The microprocessor arrives at this conclusion by
subtracting the evaporator transducer output from
the condenser transducer output. The result must be
zero or some positive number. If the result is a nega-
tive number, it concludes that there is a probable
condenser or evaporator transducer problem. This
function is inhibited for the first 10 minutes of chiller
run-time, and is checked every 10 minutes thereaf-
ter. Message is reset by pressing the WARNING RE-
SET key in the Service mode.
NOTE: If the STATUS key is arbitrarily pressed, with-
out the operator being prompted by the
PRESS STATUS
message, the following message shall be displayed.
NO MALFUNCTION DETECTED
WARNING – REFRIGERANT LEVEL OUT OF RANGE
Displayed when the refrigerant level sensor output goes
to > 4.4VDC. While this is displayed, the variable ori-
fice is driven open until the level is within range. This
message is automatically cleared when output is within
range.
SYSTEM RUN – LEAVING TEMP CONTROL
Displayed while the chiller is running. Indicates that
the pre-rotation vanes are being controlled by the leaving
chilled water temperature (LCWT). This is the normal
mode of chiller operation. Thus, if the LCWT is above
the setpoint, but pulling down rapidly, the vanes will
pulse closed as the LCW nears the setpoint.
SYSTEM READY TO START
Indicates that the system is not running, but will start
upon application of a start signal.
SYSTEM SHUTDOWN – PRESS STATUS
Displayed when chiller is shut down on a cycling shut-
down, safety shutdown (operator must move the COM-
PRESSOR switch to STOP/RESET in order to restart)
or operator-initiated shutdown (within 30 minutes of
initial start-up). The status message consists of the
day and time of shutdown, cause of shutdown, and
type of restart required. Upon pressing STATUS key,
System Shutdown Message will be displayed for 2 sec-
onds and then return to
SYSTEM SHUTDOWN – PRESS STATUS
Display can be held indefinitely by depressing DIS-
PLAY key. For examples of System Shutdown Mes-
sages, see below.
Chiller was shut down on Monday at 10:00 AM be-
cause the LCWT has decreased to a value that is 4°F
below the operator-programmed chilled liquid tempera-
ture setpoint. However, if the setpoint is less than 40°F,
the chiller will always shut down at 36°F. Further, if the
chiller is running and the setpoint is changed, the (Low
Water Temperature) cutout will be 36°F for 10 minutes
in order to eliminate nuisance trips. Finally, for brine
chilling applications, the LWT cutout is always 4°F be-
low the setpoint. (The water jumper on the Micro Board
must be removed for a brine unit.)
MON XX:XX AM – FLOW SWITCH – AUTOSTART
Chiller is shut down because a chilled-liquid flow switch
has opened. The flow switch must open for a minimum
of 2 seconds in order to cause a shutdown. The flow
switch is checked 25 seconds into “Start Sequence
Initiated” and continuously thereafter.
MON XX:XX AM – SYSTEM CYCLING – AUTOSTART
A remote command (computer relay contact or manual
switch) connected to the Remote/Local cycling input
of the digital input board has shut down the chiller.
MON XX:XX AM – MULTI UNIT CYCLING – AUTOSTART
Lead/Lag sequence control accessory has shut down
the chiller.
MON XX:XX AM – POWER FAILURE – AUTOSTART
The chiller is shut down because there has been a
power interruption or failure. The chiller will automati-
cally restart when power is restored. This message
SYSTEM SHUTDOWN MESSAGES
Day of Week Cause of Shutdown
Time of Day Type of Restart
MON 10:00 AM – LOW WATER TEMP – AUTOSTART