Duplex Chiller Control Configuration - Carrier R080-528 Installation Instructions Manual

Duplex Chiller Control Configuration —
Fig. 36-39 and Table 6. The dual chiller routine is available for
the control of two units supplying chiller fluid on a common
loop. One chiller must be configured as the master chiller, the
other as the slave chiller. The module B chiller is the master
and the module A chiller is the slave.
NOTE: Chiller module B must be configured on site as the
master chiller and module A must be configured on site as the
slave chiller for all 30GXN,R duplex chiller applications. Field
installation of communication wiring is required. Connections
can be made to the CCN screw terminals on TB3 in both
chillers.
The master chiller will be configured with a slave chiller at
address 2. The chillers will be configured for series fluid flow.
The master and slave chillers cannot have the same CCN
MODE
Configuration
LEGEND
N/R — Not Required
*Set to desired control method: switch (0); 7-day occupancy (1); CCN occupancy (2); CCN (3). Slave is
always configured to switch (0).
†Optional.
See
Table 6 — Duplex Configuration
SUB-MODE ITEM
OPT2 CTRL Controls Method
CCNA
RSET LLEN Lead/Lag Chiller Enable
MSSL Master/Slave Select
SLVA
LLBL† Lead/Lag Balance Select
LLBD† Lead/Lag Balance Data
LLDY†
PARA Parallel Configuration
SLAVE
RETURN
CHILLER
FLUID
(module A)
Fig. 39 — Dual Chiller Piping Arrangement,
Series Fluid Flow
address (CCNA, Configuration mode under OPT2). In addi-
tion, the chillers must reside on the same CCN bus. The master
chiller controls the slave chiller by changing its mode (STAT,
control mode) and its operating setpoint (CTPT, control point).
Any energy management functions need only be connected to
the Master chiller. The EMM accessory has to be installed in
the Master chiller only.
The master chiller is now configured for dual chiller opera-
tion. To configure the slave chiller, only the LLEN, MSSL, and
PARA variables need to be set. Set the Lead Lag Enable
(LLEN) variable to ENBL. Set the Master Slave Select
(MSSL) variable to SLVE. Set the Parallel (PARA) variable to
NO. The variables SLVA, LLBL, LLBD and LLDY are not
used by the slave chiller.
DESCRIPTION MASTER
Switch*
CCN Address
ENBL
MAST
Slave Address
Master Leads - 0;
Slave Leads - 1;
Automatic - 2
168 hrs.
Lag Start Delay 5 min.
MASTER
LEAVING
CHILLER
FLUID
(module B)
53
SLAVE
Switch*
1 2
ENBL
SLVE
2 N/R
N/R
N/R
N/R
No No