York YK-EP Operation And Maintenance Manual page 199

Table 201: Voltage thresholds
Supply voltage
range (Volts)
440-480
550-600
Supply Voltage
Range disabled
Starter – High Supply Line Voltage (Mod "A" Solid State Starter)
The voltage in any phase of the AC Power Line Voltage supplying the Solid State Starter has
increased to the high line voltage threshold for 20 continuous seconds. The chiller will automatically
restart when the voltage returns to the restart level. The thresholds are as follows:
Table 202: Voltage thresholds
Supply voltage range (Volts)
380
400
415
440-480
550-600
Supply Voltage Range disabled
Proximity Probe – Low Supply Voltage
This message indicates the +24VDC power supply voltage to the Proximity Probe has decreased
to +19VDC. This is below the minimum level required for reliable operation. The chiller will
automatically restart when the voltage increases to greater than or equal to 19.7VDC.
Oil – Variable Speed Pump – Drive Contacts Open
The Oil Pump Variable Speed Drive has shut down the chiller by opening its status contacts
connected to the I/O Board TB3-70. The Drive initiates a shutdown anytime its internal protection
circuits will not permit the Drive to run. The contacts remain open until its internal protection
circuits are satisfied it is safe to operate. Some Drive initiated shutdowns require AC Power to be
cycled to clear the fault. The chiller will automatically restart when the contacts close.
Mod "B" Solid State Starter cycling shutdown messages
LCSSS Initialization Failed
When AC Power is restored to the system after a power failure, an initialization process
occurs wherein the Control Center attempts to establish communications through the serial
communications link with the Liquid Cooled Solid State Starter. If communications are not
established within 10 consecutive attempts, a cycling shutdown is performed and this message is
displayed. The Control Center attempts to establish communications until successful.
LCSSS – Serial Communications
After communications have been successfully established in the Initialization process, the
Control Center initiates a data transmission to the Liquid Cooled Solid State Starter on the serial
communications link every 2 seconds. After these communications have been established, if the
Control Center does not receive a reply within 10 consecutive attempts, a cycling shutdown is
performed and this message is displayed. This same cycling shutdown is performed, along with the
YK-EP Style B Centrifugal Chiller
Shutdown Restart
(volts) (volts)
370 400
460 502
None N/A
Shutdown (Volts)
415
436
454
524
655
None
Restart (Volts)
414
435
453
523
654
N/A
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