Viessmann VITOTRONIC 300 GW2 Installation And Service Instructions Manual page 9

Circuit Diagram 1
(continued)
sÖ A1 Close mixing valves
Contactor relay, field supplied
A
Heating circuit controls
B
connected downstream
Switch contact closed: signal
for "close mixing valve".
Heating system types
Wiring diagram
Wiring of the Therm-Control in heating
systems with heating circuit control units
are not connected to the boiler control
unit via the LON.
Required coding:
Change "4C" to "2" - use the plug-in
connector 20 A1 to close the
downstream mixing valve. Change "0D"
to "1" - the Therm-Control acts on the
mixing valve of the downstream heating
circuits (for Vitotronic 200 and 300,
delivered condition).
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