YORK INTERNATIONAL
43
FORM 160.60-O1
LD00690
bearing. Therefore, a bearing inspection is not required.
However, due to the critical nature of these circuits, any-
time this shutdown occurs, a special reset procedure
must
be performed by a qualified service technician be-
fore the chiller can be restarted. This procedure is de-
tailed in service manual Form 160.60-M1.
MON XX:XX AM DC UNDER VOLTAGE
The Proximity/Temperature Sensor module becomes un-
stable in operation when the +24 VDC supply decreases
to +17VDC. Therefore, the Micro Board monitors the
+24VDC supply and when it decreases to +19VDC, it
shuts down the chiller and displays this message, pre-
venting invalid Proximity Sensor Safety or High Speed
Drain Temp safety shutdowns. The chiller will automati-
cally restart when the voltage increases to greater than
+19.7VDC. DC undervoltage is a
standard shutdown
.
FIG. 16
MICROCOMPUTER CONTROL CENTER -
LOCATION OF REAL-TIME CLOCK U16
ration temperature must equal leaving condenser water
tempe25 / 2.5°F.
REPLACE RTC.U16 – REPROGRAM SETPOINTS
Indicates that the battery located inside the
REAL-TIME
CLOCK
IC chip (U16 on the Micro Board) is defective.
This battery provides back-up power to the RTC memory
(RAM) in the event of a utility AC power failure. This as-
sures the system setpoints will be maintained. If this
message appears, the RTC IC chip (U16) on the Micro
Board must be replaced. If there had been a power failure
while this message is displayed, the setpoints will have
been lost and must be reprogrammed. Order a replace-
ment RTC IC chip (YORK Part Number 031-00955-000)
from the YORK Parts Distribution Center. With AC power
removed from system, locate RTC chip U16 on the Micro
Board and remove existing RTC chip from socket and
discard. Observe anti-static precautions and install new
RTC chip in socket.
Assure proper IC orientation -
orientation notch must be UP
. (Refer to Fig. 16).
24673A(D)
LD00691
MICRO
BOARD
U16 RTC
1C CHIP
REAL TIME
CLOCK
MON XX:XX AUX SAFETY SHUTDOWN
The system had a
quick shutdown
because an external
device, connected to digital input board TB1-31 (Auxil-
iary Safety Shutdown Input), has initiated a system shut-
down. This input is a general purpose input that can be
used to annunciate a user-defined safety shutdown. Safety
shutdown reset procedure required (page 14).
WARNING – PRV POT OR SWITCH ERROR
An error has been detected with the vane position sensor
or vane motor closed switch. Chiller will run at fixed speed
until error is corrected. May require recalibration of PRV
sensor or checkout of vane motor switch.
WARNING – CONDENSER TRANSDUCER OR PROBE ERROR
An error has been detected with the condenser pressure
transducer or leaving condenser water sensor. Chiller will
run at fixed speed until error is corrected. Condenser satu-
S
E
C
T
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