Johnson Controls YORK YK MaxE, Operation Manual

Page: 52 / 184

JOHNSON CONTROLS
52
FORM 160.54-O1
optiView Control Center
Extended Run (Enabled/Disabled)
Access Level Required: 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. If the chiller is equipped
with a compressor motor Variable Speed Drive, output
frequency must be at full speed (50 Hz/60 Hz) 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.
Count Window
Access Level Required:
OPERATOR
Allows the user to define the period of time (1 to 5
minutes; default 5;default 3 with Software version
C.MLM.01.09.xxx (and later) or C.OPT.01.09.301 (and
later)) in which the number of surge events (SURGE
WINDOW COUNT) are compared to the maximum al-
lowed (COUNT LIMIT), 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 4 ;default 15 with Software ver-
sion C.MLM.01.09.xxx (and later) or C.OPT.01.09.301
(and later)) 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 situation is detected, the action
depends upon the following:
•
If both the SHUTDOWN and EXTENDED RUN
setpoints are Disabled, the chiller will continue to
run, displaying the message “WARNING – EX-
CESS SURGE DETECTED”. See Hot Gas Bypass
and Variable Speed Drive exceptions above.
•
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”. See Hot
Gas Bypass and Variable Speed Drive exceptions
above.
•
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 – EX-
CESS SURGE DETECTED” that continues after the
10 minute period has elapsed until manually cleared
with the Warning Reset key. See Hot Gas Bypass
and Variable Speed Drive exception above.
•
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. See Hot Gas Bypass and Variable Speed
Drive exceptions above.
Surge Sensitivity
Access Level Required: SERVICE
Allows the user to define the surge detection sensitivity
of the Surge Protection feature. The Surge Sensitivity
Setpoint on the ACC Details Screen sets the sensitivity
of the ACC surge detection feature that is employed for
ACC Surge detection when configured in MODBUS se -
rial communications protocol. Selectable over the range
of 0.3 to 1.3; default 0.3. The smaller the number, the
greater the sensitivity.
Clear Surge Count
Access Level Required:
ADMIN
Allows user to set the Total Surge Count to zero.