Operating instructions

18
Heating system designs
System version 4 (cont.)
Possible applications
Heating systems with distributor
installed close to the boiler. The
boiler water volume flow will be
reduced by the motorised butterfly
valve.
In multi−boiler system without
Vitotronic 333, cascade and cylinder
control must be provided by a higher
control unit.
If the factory−set temperatures are
not reached at the ThermControl
temperature sensor, ThermControl
will regulate the motorised butterfly
valves. Where ThermControl cannot
affect the motorised butterfly valves
it must, instead, regulate the mixers
of the downstream heating circuits.
In the start−up phase (e.g. during
commissioning or after a night or
weekend shutdown), the boiler water
volume flow must be reduced by at
least 50%.
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.
Required coding: "0d:1".
Therm−Control
Wiring in heating systems with
heating circuit control units which
are not connected to the boiler
control unit via the LON BUS.
Required coding:
"0d:1" and "4C:2".
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
5862730GB
A
A
D
A
C
L1
N
PE
closed closed closed
12n...
K1 K2
B
20 20
A1 A1