Viessmann VITOTRONIC 100 GC1 Installation And Service Instructions Manual page 28

Heating system types
Circuit Diagram 11
Possible applications
The cascade and DHW tank control
must be activated by a building
automation system.
IMPORTANT
This circuit diagram represents a
recommendation only. It is the
responsibility of the customer and/or
heating contractor to check that this
recommendation is complete and fully
functional. Three-phase equipment
must be connected via additional
power contactors.
Available system accessories
Flue gas temperature sensor
Coding of Change required
system type
01: 1 Set coding "01: 3" for multi-boiler system
with external cascade control via switch
contacts
02: 1 Set coding "02: 2" for operation with
modulating burner
0d: 2 Set coding "0d: 0"
28
(continued)
The Vitocrossal 300 is operated with
constant boiler water temperature by
means of the boiler control unit.
Two-stage or modulating burners can
be controlled.
The Vitocrossal 300 has two return
connections. The heating circuits
with the higher return temperature
are connected to the return
connection at the top, those with
the lower temperatures to the return
connection at the bottom.
Please note:
At least 15% of the
take-off from the rated output must
be connected to the return connection
at the bottom.
The boiler water temperature which
is established in the heating mode is
higher than the maximum heating
circuit supply temperature by an
adjustable difference.
Motorized isolation valve
Connect motorized isolation valve
adaptor (Part No. 7134 560) or 24V
valve adaptor (Part No. 7134 559),
installed in connection enclosure, in
parallel.
Use electric junction box if necessary.
Automatic change
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