Technical data

124
Function description – Vitocontrol-S, VD2/CT3/CM2
Cascade control unit
Brief description
The supply temperature is regulated by
starting or stopping the burner or by
starting/stopping individual burner
stages.
Depending on the type of control:
The boilers will be controlled to the
set boiler water temperature
determined by the cascade control
(stand-alone type of control)
or
The cascade controls the boilers by
pre-setting an individual boiler output
(sequential control strategy).
Subject to the system design, you may
select between one gross calorific
strategy and two net calorific
strategies.
The boiler sequence (see page 129) can
be determined via coding 2 and the
boiler sequence selection.
Coding addresses which influence the
cascade control
35 to 3F, 41 to 4A.
For a description, see the coding
overview.
Set supply temperature
The set supply temperature is
determined from
The supply temperature setpoint
values of system circuit A1 and
mixing valve circuits M2 and M3,
The set supply temperature values of
additional heating circuit loads (e.g.
Vitotronic 050),
The set DHW temperature and
external demands (e.g. the set supply
temperature required by coding
address 9b or via the Input Module 0
to 10 V).
Upper control limit
Electronic maximum system supply
temperature limit.
Setting range: 20 to 127˚C / 68 to
261˚F.
The maximum supply temperature limit
can be adjusted via coding address 37.
This value must be set no higher than
the lowest value of coding address 06
of all connected Vitotronic 100, GC1.
Lower control range limit
Electronic minimum system supply
temperature limit.
Setting range: 20 to 127˚C / 68 to
261˚F.
The minimum supply temperature limit
can be adjusted via coding address 36.
5351 340 v1.4