Technical data

133
Function description – Vitocontrol-S, VD2/CT3/CM2
DHW tank temperature control
Brief description
The DHW tank control logic is a
set-point control. It is the result of
starting and stopping the DHW pump.
The switching differential is ±2.5˚C /
4.5˚F.
During DHW tank heating, a constant
boiler supply temperature will be set
(20˚C / 36˚F higher than the set DHW
tank temperature, adjustable via coding
address 60) and space heating is
switched OFF (optional DHW tank
priority).
Coding addresses which influence the
DHW tank control
54 to 75, 7F, A2.
For a description, see the coding
overview.
Functions
Time program
An automatic program or an individual
time program may be selected for DHW
heating and the control of the DHW
recirculation pump.
Compared with the space heating
circuit’s heat-up phase, DHW heating
in automatic mode starts 30 minutes
earlier.
The individual time program enables up
to four switching periods per day to be
set via the time switch to control the
DHW heating/heating and the DHW
recirculation pump.
Any DHW tank heating sequence will
be completed, independent of the time
program.
In conjunction with coding address 7F
7F: 1 Detached house:
Automatic mode:
For systems with two or three space
heating circuits, the heating times for
the first of the existing heating
circuits will be applied.
Individual time program:
The switching times for DHW heating
and the DHW recirculation pump
have the same effect on all heating
circuits.
7F : 0 Apartment building:
Automatic mode:
For systems with two or three
heating circuits, the heating times
for the respective heating circuit
will be applied.
Individual time program:
The switching times for DHW heating
can be adjusted separately for each
heating circuit.
DHW priority
With DHW priority (coding A2: 2):
The set supply temperature will be
set to 0˚C / 32˚F while the DHW
tank is being heated.
The mixing valve closes, and the
heating circuit pumps are switched
OFF.
With DHW priority:
The heating circuit control unit
continues to operate with the same
set value.
Frost protection
The DHW tank will be heated to 20˚C /
68˚F, if the DHW temperature falls
below 5˚C / 41˚F.
Auxiliary functions – DHW heating
This function is activated by providing
a second set DHW temperature via
coding address 58 and activating the
4
th
DHW phase for DHW heating.
Set DHW temperature
The set DHW temperature can be
adjusted between 10 and 60˚C / 50
and 140˚F. The set range can be
expanded to 95˚C / 203˚F via coding
address 56.
You can select the set DHW
temperature at the programming unit of
the control and at every Vitotrol 300
remote control unit (if installed).
You can determine the allocation to
individual heating circuits via coding
address 66.
DHW recirculation pump
It delivers hot water to the draw-off
points at adjustable times. Up to four
control periods can be set at the timer.
Auxiliary circuits
The DHW heating can be disabled or
enabled by changing over the heating
program.
System with DHW tank heating system
The above functions also apply in
conjunction with calorifiers.
Set the following codings:
4C: 1, 4E: 1, 55: 3.
For a description, see the coding
overview.
Systems with Vitosolic
A third DHW temperature set-point can
be programmed via coding address 67.
Reloading suppression will be active
below the set temperature. The DHW
tank is heated only by the solar heating
system.
5351 340 v1.4