York YK-EP Operation And Maintenance Manual page 190

System run – Cooling mode
The chiller is running with Heat Pump Duty enabled and the Heat Pump Duty Operational mode
setpoint set to Cooling mode. In this mode, the Heat Pump is controlling the Leaving Chilled Liquid
Temperature to the Leaving Chilled Liquid Temperature Setpoint.
System coastdown
The chiller has shut down and the Post-run lubrication is being performed. The Coastdown
duration is determined by the setting of the Coastdown (standard or enhanced) and Coastdown
Time Setpoints. If the Coastdown setpoint is set to enhanced (steam turbine applications), it
is 15 minutes. If set to standard (electric motor applications), it is programmable over a range
determined by the Chiller Style/Compressor Setpoint (for style G/K6-K7, the range is 240 (default) to
900 seconds.
Start inhibit
The chiller is prevented from being started due to the reason displayed on the Details Line of the
Status Bar.
Vanes closing before shutdown
Displayed while the Pre-Rotation Vanes are closing during a Soft Shutdown. During Soft Shutdowns,
the Vanes are driven fully closed prior to shutting down the compressor. When the Vane Motor End
Switch closes, indicating the Vanes have fully closed (or 3.5 minutes have elapsed, whichever occurs
first), the Run Signal is removed from the compressor motor starter and a System Coastdown is
performed. Soft Shutdowns are initiated by the following:
1. Leaving Chilled Liquid – Low temperature
2. Remote Stop
3. Multi-Unit Cycling – Contacts Open
4. System Cycling – Contacts Open
5. Control Panel – Schedule
6. Operator Initiated at Keypad
While the Vanes are closing during any Soft Shutdown, if a Local Stop is initiated with the
Compressor Switch or any faults other than those listed above occur, the Soft Shutdown is
terminated and it will immediately perform a System Coastdown.
Run messages
Leaving chilled liquid control
The chiller is running, controlling the Leaving Chilled Liquid to the Leaving Chilled Liquid
Temperature Setpoint. There are no system conditions inhibiting this operation.
Heat pump – Leaving chilled liquid control
The Heat Pump is running, controlling the Leaving Chilled Liquid Temperature to the Leaving
Chilled Liquid Temperature Setpoint. In this mode, Heat Pump Duty is enabled and the Heat Pump
Duty Operational mode setpoint is set to Cooling mode.
Current pulldown limit
The Pulldown Demand Limit Setpoint timer is in effect and the Compressor Motor current is
greater than or equal to the Pulldown Demand Current Limit Setpoint value. The Pre-Rotation Vane
operation is being inhibited as described in Motor – High Current Limit message below.
190 YK-EP Style B Centrifugal Chiller