York YK-EP Operation And Maintenance Manual page 62

Table 48: Programmable
Button Access level
Shutdown
(Enabled/ Operator
Disabled)
Extended
Run
Operator
(Enabled/
Disabled)
62
Description
Allows the user to select whether the chiller will shutdown or
continue to run when an Excess Surge situation has been detected.
If this setpoint is Enabled and the Extended Run Setpoint is
Disabled, a safety shutdown is performed when the Surge Window
Count exceeds the Count Limit Setpoint.
If this setpoint is Enabled and the Extended Run Setpoint is Enabled,
a safety shutdown is performed if the Surge Window Count exceeds
the Count Limit Setpoint at the completion of the 10 minute
Extended Run period.
Surge Protection – Excess Surge is displayed with either shutdown.If
this setpoint is Disabled, refer to operation under Count Limit in this
section.
• If equipped with a compressor Variable Speed Drive (VSD),
the VSD output frequency must be at maximum before
the Shutdown feature is implemented or Surge Warning
messages are displayed.
• If equipped with a VSD and Hot Gas Bypass (Enabled), the VSD
output frequency must be at maximum and the Hot Gas Valve
must be at 100% before the Shutdown feature is implemented
or Surge warning messages are displayed.
Allows the user to select the surge correction/avoidance Extended
Run mode. This will be implemented when an Excess Surge situation
is detected as follows:
Anytime the Surge Window Count exceeds the Count Limit, the Pre-
Rotation Vanes are driven closed for the next 10 minutes. While
this load inhibit is in effect, WARNING – SURGE PROTECTION –
EXCESS SURGE LIMIT is displayed. When 10 minutes have elapsed,
the warning message and load inhibit are automatically cleared,
provided the Surge Window Count is less than or equal to the Count
Limit. If the Shutdown Setpoint is Enabled, and the Surge Window
Count exceeds the Count Limit at the completion of this period, a
safety shutdown is performed and Surge Protection – Excess Surge
is displayed.
If the Hot Gas Bypass control is Enabled, the Hot Gas Bypass
Valve position must be 100% before the Extended Run mode is
implemented. If the chiller is equipped with a Compressor Motor
Variable Speed Drive, output frequency must be at full speed
(50Hz/60Hz) before the Extended Run mode is implemented. If the
chiller is equipped with both Hot Gas Bypass and Compressor Motor
Variable Speed Drive, both of the conditions must be met before
Extended Run is implemented.
YK-EP Style B Centrifugal Chiller