Machine Communication Wiring
Refer to the machine’s Ins tallation Instructi ons and Carrier Comfort Network Interface section
for information on machine communication wiring.
Lead/Lag Oper ation
The PIC control provide s the ability to operate 2 c hil lers in the LEAD/LAG mode. It also
provides the additio nal ability to start a desig nated standby chille r when either the lead or la g
chiller is faulted and ca pac i ty requirements ar e no t met. The lead/lag op ti on operates in CCN
mode only. If any other ch ill er configured for le ad/ lag is set to the LOCAL or OF F mod es, it will
be unavailable for lea d/ lag operation.
Note: Lead/lag configu ration is viewe d and edited in Lead/Lag, under the Equ ipment Configu-
ration table of the Service menu. Lead/lag status during machine oper ation is viewe d in
the MAINT04 table in the Con trol Algorithm Sta tu s table.
Lead/Lag Chiller Configuration and Operation
The configured lead chil ler is ide ntified when the LEAD /L AG SELECT value for that chil ler is
configured to t he value of ‘‘1.’’ The conf igured lag chi ller is iden tified when t he LEAD/LAG
SELECT for that chille r is co nf igured to the value of ‘‘2. ’’ The standby chille r is configured to a
value of ‘‘3.’’ A value of ‘‘0 ’’ disables the lead/ lag in that chiller.
To configure the LAG ADDRESS value on the L EAD/LAG Configuration table, always use
the address of the other chiller on the system for this value. Using this address will ma ke it
easier to rota te the lead a nd lag machines .