York YK-EP Operation And Maintenance Manual page 197

Oil – Low Temperature
The oil temperature has decreased to less than 55°F. The chiller will automatically restart when
the temperature increases to greater than 55°F and is greater than the Condenser Saturated
temperature by 30 or 40°F, as described above in the Oil – Low Temperature Differential message
description.
Control Panel – Power Failure
A Control Power failure has occurred. If the power failure occurred while the chiller was running, it
will automatically restart when power is restored. However, if the power failure duration was less
than the duration of the applicable coastdown period (2.5 minutes standard; 15 minutes steam
turbine) when power is restored, the remainder of the coastdown will be performed, prior to the
chiller starting. This message can indicate a Cycling (auto-restart after power failure) or Safety
(manual restart after power failure) shutdown, depending upon Control Center configuration.
It indicates a cycling shutdown when displayed in orange characters; safety shutdown when
displayed in red characters. The Control Center is configured for auto-restart or manual restart
after power failure by a qualified Service Technician.
Leaving Chilled Liquid – Low Temperature
The Leaving Chilled Liquid Temperature has decreased to the programmed Shutdown Temperature
Setpoint. If the chiller is running when this occurs, the Pre- Rotation Vanes are driven fully closed
prior to shutting down the chiller. The chiller will automatically restart when the temperature
increases to the programmed Restart Temperature Setpoint.
Leaving Chilled Liquid – Flow Switch Open
The Chilled Liquid Flow Switch has remained open for 5 continuous seconds while the chiller was
running or failed to close during the System Prelube period. The chiller will automatically restart
when the flow switch closes.
While this cycling shutdown is active, the evaporator pump relay contacts (TB2-44/45) remain
closed until the chiller is given a stop command or has another fault.
Condenser – Flow Switch Open
The condenser water flow switch has remained open for 30 continuous seconds while the chiller
was running. This check is bypassed for the first 30 seconds of System Run. The chiller will
automatically restart when the flow switch closes.
While this cycling shutdown is active, the condenser pump contacts (TB2-150/151) remain closed
until the chiller is given a stop command or has another fault.
Motor Controller – Contacts Open
The CM-2 Current Module (Electromechanical starter applications) or Solid State Starter Logic
Board (Mod "A" Solid State Starter applications) has shutdown the chiller. When detecting a fault
condition that places the starter or motor at risk, these devices open the Motor Controller contacts
"CM" (located on the respective device and connected between TB6-16 and TB6-53 in the Control
Center) to initiate a shutdown. Since there are several different faults that are monitored, LED's
on the respective device illuminate to identify the specific fault that has occurred. Refer to Solid
State Starter (Mod "A") – Operation and Maintenance (Form 160.46-OM3.1) for details of Mod "A" Solid
State Starter initiated shutdowns and the OptiView Control Center Service Manual for CM-2 initiated
shutdowns. The chiller will automatically restart when the Motor Controller contacts close. On some
shutdowns, the respective device automatically closes the contacts when the fault condition clears.
Other shutdowns require the Operator to perform a Manual Reset at the respective device.
YK-EP Style B Centrifugal Chiller 197