If the lag chiller faults whe n the lead chiller is also fau lted, the standby chill er r ev er t s to a
stand-alone CCN mode of ope ration.
If the lead chiller is in an alarm (*) condition (as shown on the LID panel), the RESET softkey
is pressed to clear t he alarm, and the chil ler is placed in the C CN mode, the lead chil ler will now
communicate and m onitor the RUN STATUS of the lag and standby chill ers. If both the lag and
standby chillers are running, the lead chiller will not att empt to start and will not assume the role
of lead chiller until either the lag or standb y chiller shuts d own. If only one chiller is runn ing, the
lead chiller will wait for a s t art request from the ope r at ing chiller. When the conf ig ured lead
chiller starts, it ass um e s its role as lead chiller.
Load Balancing
When the LOAD BALANCE OPT ION is enabled, the lead chil ler will set the ACTIVE DE-
MAND LIMIT in the lag chiller to the lead chiller’s COMPRESSOR MOTOR LOAD value. This
value has limits of 40% to 100%. When setting the lag chiller ACTIVE DEMAND LIMIT, the
CONTROL POINT shall be m od ified to a value of 3° F (1.67° C) les s th an the lead chiller’s
CONTROL POINT value. If the LOAD BALANCE OPTION is disabled, the ACTIVE DEMAND
LIMIT and the CONTROL POI NT are forced to the same val ue as the lead chiller.