Riello NXHP Series Installation, Operation And Maintenance Instructions page 58

4 -OPERATION
f - DHW schedule
Refer to WUI end user manual or DHW schedule parameters (P720 to P732, see § 7.1 )
Example of DHW scheduling
Step nb
MON
1
X
2 X
3 X
4
1 2 3
MON
TUE
WED
THU
FRI
SAT
SUN
Hol.
DHW regular setpoint
DHW Eco Setpoint
Anti-legionella
Space heating/cooling
4.2.15 - Master/Slave
a- Installation
Master/slave installation permits connection for multiple units in
parallel: one master unit can control several slave units.
This kind of installation must comprise the same unit size (for
example all 4 kW units or all 12 kW units, but not a mix of different
sizes).
The master / slave operation is incompatible with Domestic Hot
Water production.
Only the Master unit can be fitted with user interface options. If
the Slave units have been ordered with a user interface, then it is
necessary to disconnect it.
Additional common leaving water temperature sensor must be
installed on site, on the common piping.
Accessory
Resistance = 5 KOhms
Characteristics
Cable length = 15 m
Electrical
- Refer to § 3.7 Master/Slave installation
connection
- Refer to § 3.7 Master/Slave installation
Configuration
The RS485 communication cable (not supplied) must be connected
on each unit.
58
Day of week and holyday
TUE WED THU
X X X
X X X
X X X
4 5 6 7 8
FRI SAT
X X
X X
X X
9 10 11 12 13 14
b- Control
All units installed in the same master/slave group share the same
operating mode as well as the same setpoint.
The Master unit is connected to a user interface which can be
installed remotely. The "Master" user interface is a decision point
for all other units in the same master/slave group, which means
that the operating mode (cooling / heating) and the water setpoint
defined by the master will be transmitted to other "slave" units.
When there are at least two units configured in the master/slave
assembly, it is possible to define how compressors are started.
Three compressor control methods are available.
Compressors can be started:
Based on address configuration: The Master unit is started first.
Then, slave units will be started sequentially (beginning with slave
1 and ending with, for example, slave 3). When stopping, the last
slave is stopped first – the Master is the last unit stopped.
According to wear factor: Units are started sequentially based on
the wear factor. As system demand increases, the unit with the
lowest wear factor is started first, when system demand decreases
capacity, the unit with, the highest wear factor is stopped first.
Simultaneously: All units are started and stopped at the same
time. Compressor frequency is increased or decreased
simultaneously on all units.
For more details on Master /Slave icon display on WUI, refer to
WUI end-user manual.
CAUTION:
In the case of master/slave communication failure, the Master
will either run in the standalone mode or it will continue to
operate with other Slave units that are still communicating.
The affected Slave unit will stop all of its operations.
Start time
SUN Hol.
X 02:30
X 15:00
X 20:30
X 06:00
15 16 17 18 19 20
End time
06:30
17:00
22:30
10:00
21 22 23