Carrier 17/19EX - Manual (Page 98)

Machine Communication Wiring
Refer to the machine’s Installation Instructions and Carrier Comfort Network Interface section
for information on machine communication wiring.
Lead/Lag Operation
The PIC control provides the ability to operate 2 chillers in the LEAD/LAG mode. It also
provides the additional ability to start a designated standby chiller when either the lead or lag
chiller is faulted and capacity requirements are not met. The lead/lag option operates in CCN
mode only. If any other chiller configured for lead/lag is set to the LOCAL or OFF modes, it will
be unavailable for lead/lag operation.
Note: Lead/lag configuration is viewed and edited in Lead/Lag, under the Equipment Configu-
ration table of the Service menu. Lead/lag status during machine operation is viewed in
the MAINT04 table in the Control Algorithm Status table.
Lead/Lag Chiller Configuration and Operation
The configured lead chiller is identified when the LEAD/LAG SELECT value for that chiller is
configured to the value of ‘‘1.’’ The configured lag chiller is identified when the LEAD/LAG
SELECT for that chiller is configured to the value of ‘‘2.’’ The standby chiller 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 LEAD/LAG Configuration table, always use
the address of the other chiller on the system for this value. Using this address will make it
easier to rotate the lead and lag machines.