Viessmann VITOTRONIC 100 Installation And Service Instructions Manual page 13

System version 2
Possible applications
Heating systems with distributor
installed close to the boiler. The
boiler water volume flow must be
able to be reduced.
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.
Size the shunt pump to approx. 30 %
of the total throughput capacity of
the boiler.
(cont.)
Heating system designs
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: "4C:
20
A1
20
N L
A
closed
B
sÖ A1 Mixers closed
A
Contactor relay,
part no. 7814 681
B
Downstream heating circuit
controller, contact closed:
Signal for "Mixer closed".
2".
closed closed
13