York YD Mod D, Operation Manual, Page: 58 / 160

Table 43: Programmable
Button Access level Description
Shutdown
(enabled/
disabled)
Operator
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 in
Count limit .
Extended run
(enabled/
disabled)
Operator
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.
Count window Operator
Allows the user to define the period of time (1 to 5 minutes; default 3) in which the
number of surge events (SURGE WINDOW COUNT) are compared to the maximum
allowed (COUNT LIMIT), for the purpose of detecting an excess surge situation.
Count limit Operator
Allows the user to define the maximum number of surge events (4 to 20; default 15)
that can occur within a defined period of time before an Excess Surge situation is
detected. If the SURGE WINDOW COUNT exceeds the COUNT LIMIT, an Excess Surge
situation has occurred.
When an Excess Surge is detected, the action depends upon the situation:
• If both the SHUTDOWN and EXTENDED RUN setpoints are Disabled, the chiller
will continue to run, displaying the message “Warning – Excess Surge detected”.
• If the SHUTDOWN setpoint is Enabled and the EXTENDED RUN setpoint
is Disabled, the chiller will perform a safety shutdown and display “Surge
Protection – Excess Surge”.
• If the SHUTDOWN setpoint is Disabled and the EXTENDED RUN setpoint is
Enabled, the Pre-rotation Vanes are driven closed for 10 minutes and “Warning
– Surge Protection – Excess Surge Limit” is displayed. When the 10 minutes
have elapsed, if the SURGE WINDOW COUNT is less than or equal to the COUNT
LIMIT, this message and load inhibit are automatically cleared. Alternating with
this message is “Warning – Excess Surge Detected” that continues after the 10
minute period has elapsed until manually cleared with the Warning Reset key.
• If both the SHUTDOWN and EXTENDED RUN setpoint are Enabled, the 10 minute
Extended RUN mode is invoked as described above. However, if the SURGE
WINDOW COUNT exceeds the COUNT LIMIT at the completion of the 10 minute
extended run period, a safety shutdown is performed and “Surge Protection –
Excess Surge” is displayed.
Surge sensitivity Service
Allows the user to define the surge detection sensitivity. Selectable over the range of
0.3 to 1.3; default 0.3. The smaller the number, the greater the sensitivity.
Clear surge count Admin Allows user to set the Single Compressor Total Surge Count to zero.
Model YD Mod D with OptiView Control Center 58