Johnson Controls YORK OPTIVIEW CONTROL CENTER, Operation Manual

Page: 41 / 142

JOHNSON CONTROLS
41
SECTION 2 - OPTIVIEW OPERATION
FORM 160.10-O1
ISSUE DATE: 4/27/2018
2
Total Surge Count
Displays the total number of surge events detected over
the lifetime of the unit (up to a maximum of 65535).
These are the surge events detected by the surge pro-
tection feature. The surge events detected by the com-
pressor VSD adaptive capacity control board (ACC)
are not included in this total.
Extended Run Time Remaining
Displays the time remaining in the ten minute “Extend-
ed Run” period. During this period, the pre-rotation
vanes are driven closed and “WARNING – SURGE
PROTECTION – EXCESS SURGE LIMIT” is dis-
played. Refer to operation under “Count Limit”.
PROGRAMMABLE
Count Window
Access Level Required: OPERATOR
Allows the user to define the period of time (1 to 5
minutes; 3 minutes is default) in which the number of
surge events (Surge Window Count) are compared to
the maximum allowed (Count Limit). This is used for
the purpose of detecting an excess surge situation.
Count Limit
Access Level Required: OPERATOR
Allows the user to define the maximum number of
surge events (4 to 20; default is 15) that can occur
within a defined period of time (count window) before
an excess surge situation is triggered. If the number
of surges occurring within window time exceeds the
count limit, an excess surge situation is signaled.
When an excess surge situation is detected, the action
resulting from the situation depends upon the follow-
ing:
• If both the shutdown and extended run setpoints
are disabled, the chiller will continue to run, dis-
playing the message “WARNING – EXCESS
SURGE DETECTED”.
• If the shutdown setpoint is enabled and the ex-
tended 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 ex-
tended run setpoint is enabled, the pre-rotation
vanes are driven closed for ten (10) minutes and
“WARNING – SURGE PROTECTION – EX-
CESS 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 mes-
sage 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 manu-
ally cleared with the Warning Reset key.
• If both the shutdown and extended run setpoint are
Enabled, the ten (10) minute extended run mode
is invoked as described previously. However, if
the surge window count exceeds the count limit
at the completion of the ten (10) minute extended
run period, a safety shutdown is performed and
“SURGE PROTECTION – EXCESS SURGE” is
displayed.
If the chiller is equipped with a VSD and/or hot gas
bypass, there are several exceptions related to VSD
and/or hot gas bypass equipped chillers for the surge
correction/avoidance features to operate. These excep-
tions are as follows:
• If the hot gas bypass control is enabled, the valve
position must be 100% before the shutdown or ex-
tended run feature is implemented.
• If the chiller is equipped with a VSD, output fre-
quency must be at full speed (50 Hz/60 Hz) before
the shutdown or extended run feature is imple-
mented.
• If equipped with a VSD and hot gas bypass, the
VSD output frequency must be at maximum and
the hot gas valve must be at 100% before the shut-
down or extended run feature is implemented.
Shutdown (Enabled/Disabled)
Access Level Required: OPERATOR
This selectable feature allows the user to select wheth-
er 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.