chilled water sensor sh oul d be installed. If this se ns or is no t installed, the retur n c hil led water
sensor of the downstrea m chiller must be relocat ed t o the return chilled water pi pe of the
upstream machin e.
To properly control the common supply point temper at ure sensor when chille r s ar e pip ed in
parallel, the water fl ow t hrough the shutdown chill ers must be isolated so that no water bypass
around the oper ating chiller occu rs. The common po int sensor option must not be used if water
bypass around the oper at ing chiller is occurring.
Machine Communication Wiring
Refer to the machine’s Installation Inst ructions, Carrier Com fort Network Interfa ce section for
information on machin e communication wiring.
Lead/Lag Oper ation
The PIC control provide s the ability to operate 2 chil lers in the LEAD/LAG mode. It als o
provides the additio nal ability to start a designat ed standby chiller when either the lead or lag
chiller is faulted and ca pac i ty requirements are no t met . The lead/lag option op er at es in CCN
mode only. If any other ch ill er configured for lead/ la g is set to the LOCAL or OFF mod es , it will
be unavailable for lea d/ lag operation.
Note: Lead/lag configu ration is viewed and edited in Lead/Lag, under the Equipment C onfigu-
ration table of the Service me nu. Lead/lag st atus during mac hine operation i s viewed in
the MAINT04 table in the Con trol Algorithm Statu s tab le.