Carrier 30RBP-170R - Page 68

12.2.5 - Operation of two units in a Master/Slave
assembly
The customer must connect both units with a communication bus
using a 0.75 mm² twisted, shielded cable (contact the manufacturer's
Service for the installation).
All the parameters required for the Master/Slave function must be
congured using the Service conguration menu.
All remote controls of the master/slave assembly (start/stop,
setpoint, load shedding, etc.) are managed by the unit congured
as the Master and must only be applied to the Master unit.
Units supplied with hydraulic module
Master/Slave operation is possible only when the units are installed
in parallel:
- The Master/Slave assembly is controlled on the water inlet
without any additional sensors (system return) (Example 1).
- This can also be done on the water outlet with the addition of
two additional sensors on the common pipe (see Example 2).
Each unit controls its own water pump.
Units supplied without hydraulic module
In the case of units installed in parallel, and if there is only one
common pump installed by the installer, isolating valves must be
installed on each unit. These should be controlled (opened and
closed) using the control for the relevant unit (valves for each unit
can be controlled using the water pump control outputs). Refer to
the control manual for the connections.
In this case, a variable-speed pump must be controlled by
the unit via the 0-10 V dedicated output of the Master unit (control
on Delta T only).
An installation in series is only possible with a xed-speed pump
(See Example 3):
- The operation of the pump will be controlled by the Master
unit.
- The Master/Slave assembly is controlled on the water outlet
without additional sensor.
- The installation must be carried out only by following the
diagram provided in Example 3.
IMPORTANT:
Both of the units must be equipped with an option to allow
Master/Slave operation.
If one or both units is equipped with the variable-speed pump
option, it is strongly recommended not to set the control
mode on the pressure dierential. It is recommended to
congure the temperature dierential mode with the same
setpoint.
Example 1: operation in parallel - control on water
inlet for a hydraulic module
1
2
Example 2: operation in parallel - control on water
outlet for a hydraulic module
1
2
T
T
Example 3: operation in series - control on water
outlet for a unit assembly
2 1
Key:
All dimensions are given in mm.
B
Master unit
C
Slave unit
Water inlet
Water outlet
Control boxes of the master and slave units
Water pumps for each unit (normally included in the units with hydraulic
module)
T
Additional sensor for water outlet control, to be connected to channel 1 of
the slave boards of each master and slave unit
CCN communication bus
Connection of two additional sensors
Non-return valve
12 - OPTIONS
68