Viessmann Cascade control unit Installation, Operating And Service Instructions page 25

Set flow temperature
Flow temperature for external demand
If the "External demand" contact is closed, the flow temperature will be raised
to the set value.
Set values (multi-boiler control unit)
External
demand
In the "Operating details" menu (see page 15) you can scan whether the
control unit is set to "External demand/heat demand via Viessmann 2-wire
BUS".
Operating details (multi-boiler control unit)
Heat demand
via 2-wire BUS
(cont.)
Heat demand via external contact.
The temperatures are then displayed during the
next scan (actual flow temperature, set flow
temperature).
Heat demand from Vitotronic 050.
Functions
25