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This feature applies to all com pres sor codes. However,
if com pres sor code other than "P", applies to Flash
Memory Card versions C.MLM.01.05.xxx and later.
The SURGE PROTECTION feature detects surge
events and provides a running count of the events that
occur over the lifetime of the chiller (up to a maximum
of 65535). If excess surging is de tect ed, it can be con-
fi g ured to shut down the chiller or initiate a special surge
cor rec tion/avoid ance mode or simply display a warning
mes sage.
The SURGE PROTECTION Screen, ac ces si ble from the
COMPRESSOR Screen, displays all parameters relevant
to this feature. All setpoints relating to this fea ture are
maintained on this screen.
SURGE DETECTION
Surge events are detected by monitoring the re la tion ship
between the Condenser pressure and Evap o ra tor pres-
sure while the chiller is running. When the dif fer ence
between these pressures decreases transiently and re-
mains so for a period of time described below, and then
makes a positive transition within 7 seconds, a surge
event has been detected.
The surge detection sensitivity can be adjusted with
the SURGE SENSITIVITY setpoint. It is adjustable
over the range of 0.3 to 1.3 in 0.1 increments. Default
value is 0.3. The smaller the number, the greater the
sen si tiv i ty.
The Evaporator pressure transducer output is sub tract ed
from the Condenser pressure output to determine the
differential. If either of the following negative tran si -
tions occur in the differential followed by a 0.061VDC
positive differential transition within 7 seconds, a surge
event is detected:
• If the differential decreases > 0.6VDC for > 0.260
sec onds.
• If the differential decreases > x.xVDC for > 0.390
seconds.
x.xVDC calculated as [(surge sen si -
tiv i ty setpoint x 300) x 1.22] ÷ 1000
YORK INTERNATIONAL
SECTION 22
SURGE PROTECTION
Each time a surge event is detected, the SURGE DE-
TECT ED LED indicator on the SURGE PRO TEC TION
Screen il lu mi nates for 5 seconds and the TOTAL SURGE
COUNT in cre ments 1 count.
The TOTAL SURGE COUNT can be reset to zero us-
ing the CLEAR SURGE COUNT key with the ADMIN
access level.
EXCESS SURGE DETECTION
An excess surge condition is detected by comparing the
number of surge events that occur in a selectable time
period to a selectable threshold.
If the number of surge events (Surge Window Count)
detected in the time period programmed as the COUNT
WINDOW setpoint (1 to 5 minutes; default 5) exceed the
threshold programmed as the COUNT LIMIT setpoint
(4 to 20; default 4) an excess surge condition has been
detected.
Unless the SHUTDOWN or EXTENDED RUN fea tures
have been enabled, as explained below, the chiller will
continue to run under the same conditions dis play ing
"Warning – Excess Surge Detected". This message will
be displayed until manually reset with the Warning Reset
key in Operator access level.
SURGE PROTECTION
The Control Center can be confi gured to take the fol-
low ing courses of action when an excess surge con di tion
has been detected. The SHUTDOWN setpoint is used
to invoke a safety shutdown. The EXTENDED RUN
setpoint is used to invoke a special 10 minute surge
correction/avoidance mode that temporarily eliminates
the conditions causing the surging, while allowing
the chiller to continue to run. However, if the Hot
Gas By pass control is Enabled, the Hot Gas Bypass
Valve po si tion must be 100% before the Extended Run
mode is implemented. If the chiller is equipped with
a com pres sor motor Variable Speed Drive, the output
frequency must be at full speed (50 Hz/60 Hz) before the
the Ex tend ed Run mode is implemented. If the chiller
is equipped with Hot Gas Bypass and compressor mo-
tor Variable Speed Drive, both conditions must be met
be fore Extended Run is implemented.
FORM 160.54-M1(503)
22
131
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