Operating instructions

21
Heating system designs
System version 5 (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.
Temperature sensor T2 activates the
shunt pump, if the actual
temperature falls below the required
minimum return temperature. If the
minimum return temperature is not
reached even if the return
temperature is raised, the volume
flow must be reduced by at least
50% via temperature sensorT1, via
the butterfly valve or the heating
circuit control units. Where the
temperature sensorT1 cannot
control the butterfly valve it must,
instead, regulate the mixers of the
downstream heating circuits.
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.
Required coding: "0d:1".
Temperature sensorT1
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