Viessmann VITOTRONIC 100 Installation And Service Instructions Manual page 24

Heating system designs
System version 6
Possible applications
Heating systems with distributor
installed close to the boiler. The
boiler water volume flow must be
able to be reduced via the heating
circuits.
In multi−boiler system without
Vitotronic 333, cascade and cylinder
control must be provided by a higher
control unit.
Temperature sensor T2 activates the
shunt pump, if the actual
temperature falls below the required
minimum return temperature. If the
required minimum return
temperature is still not achieved, the
boiler water volume flow must be
reduced via temperature sensors T1.
Size the shunt pump to approx. 30 %
of the total throughput capacity of
the boiler.
The boiler is best protected when
regulating the heating circuits via
Vitotronic 050 connected to the
boiler control unit.
No additional on−site protective
measures are required.
24
(cont.)
Temperature sensor T2 and the
shunt pump must be connected to
one of the Vitotronic 100 if an
external cascade control unit is used.
Temperature sensor T1
Wiring for reducing the volume flow
in heating systems with heating
circuit control units, which are not
connected to the boiler control unit
via the LON BUS.
Required coding: "0d:
"4C: 2".
L1
C
N
PE
20 A1 20 A1
A
A
sÖ A1 Mixers closed
A
Contactor relay,
part no. 7814 681
B
Downstream heating circuit
controller, contact closed:
Signal for "Mixer closed".
C
Mains electrical connection
230V~/50 Hz
D
Junction box, on site
1" and
K1 K2
D
A
closed closed closed
B
1 2 . . . n