19
8.2.2 - Unit without hydronic module option
legend
1
Control valve
2
Air vent
3
Flow switch for the water heat exchanger (supplied)
4
Flexible connection
5
Heat exchanger
6
Temperature sensor (supplied)
7
Drain
8
Buffer tank (if needed)
9
Filter (mesh size: 1.2 mm = 20 mesh)
10 Expansion tank
11 Fill valve
Typical water circuit diagram - without hydronic module
8.3 - Flow control
All units are equipped with a factory-set flow switch, as
standard. The unit must be interlocked with the chilled-water
pump, if the unit is not equipped with the hydronic option
module.
Terminals 34 and 35 are provided for field installation of the
chilled water pump interlock (auxiliary contact for pump
operation to be wired on site).
8.4 - Frost protection
The standard unit does not include any particular frost
protection when it has shut down. It is therefore essential to
check that there is no risk of the water in the hydronic circuit
freezing during winter temperature conditions. If this may be
the case it is essential to add an appropriate anti-freeze solution
to protect the hydronic circuit down to the minimum
temperature minus 10 K.
Another solution consists of draining the hydronic circuits
exposed to temperatures below 0°C. If the unit is not used for
an extended period, protect it by circulating a protective
solution. Please consult a specialist.
A third solution is to order the ‘water heat exchanger frost
protection’ option (factory-installed - an electric heater on the
water heat exchanger).
Anti-freeze solutions and heaters can be combined. If the
hydronic module option is installed, frost protection of this
module is included (electric heater).
If protection by electric heater is used, do not switch off the
power supply to the unit.
IMPORTANT: The main unit disconnect switch, the auxiliary
heater protection switch as well as the control circuit switch
must always remain closed (to locate the components, please
refer to the wiring diagram).
8.5 - Operation of two units in master/slave mode
For this type of operation the ‘Twinning’ option must be
ordered. The units supplied are then equipped with an
additional sensor connected to the electronic board and located
in the control box. This sensor must be used when master/slave
assembly control at the water outlet is used (it is not required
for entering water control).
The customer must connect the two units via a communication
bus (0.75 mm
2
, twisted and shielded). Consult the 30RB/RQ
Pro-Dialog Plus control manual for the connection addresses.
Master/slave operation is only possible, when the units are
installed in parallel. It is not possible, if the units are installed
in series.
All parameters, required for the master/slave function must be
configured using the Service Configuration menu. All remote
controls of the master/slave assembly (start/stop, set point, load
shedding etc.) are controlled by the unit configured as master
and must only be applied to the master unit.
Each unit controls its own water pump. If there is only one
common pump, in cases with variable flow, isolation valves
must be installed on each unit. They will be activated at the
opening and closing by the control of each unit (in this case the
valves are controlled using the dedicated water pump outputs).
See the 30RB/RQ Pro-Dialog Plus Control IOM for a more
detailed explanation.
1
2
4
5
7
8
9
10
11
3
6
6
