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Electrical connections
7.11 Units connected in cascade
The cascade function of the system supports a maximum of 6 units.
7.11.1 Water connections
The water connection should preferably be an inverted return connection for better water balance be-
tween the dierent units.
It is also mandatory to install non-return valves in parallel units to stop the flow through the unit from short
circuiting when the circulator is not running.
7.11.2 Electrical connections
Use shielded wire in M/S cascade connections.
The shielding layer must be earthed.
To ensure successful auto-addressing, all units must be connected to the same power supply and evenly
powered.
7.11.3 Configuration
Only one unit at any one time is configured as the system master.
On a M/S network, only one unit needs to be configured as master; configure SW9 as per Fig 60:
Only the master unit can connect the master controller.
7.11.4 Backup master unit
It is possible to configure a unit as a backup master, preventing the interruption of certain functions should
the master fail. To configure a backup master, dip-switch 3 of the S4 must be set to On
At start-up, the service parameters must be configured independently on both the HMI of the master and
the backup master. This can be done by setting the former and copying the parameters to the backup unit
via USB. This is the only way to ensure that when the master fails, the other will provide the system with the
same pre-loaded functions.
Switching from the Master to the Backup Master will only take place in the event of major system alarms and
only the state (On/O), Mode (Hot/Cold) and setpoint operation parameters are copied. The remaining user
setting parameters are not transferred to the system in case of problems. It is therefore advisable to copy
that set on the Master to the backup master on a regular basis to prevent loss of the desired settings
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