Viessmann VITOTRONIC 300 Operating Instructions Manual page 53

Terminology
(cont.)
Factory settings: Slope = 1.4 and level = 0.
110
C
Fig. 46
Changing the slope:
A
The gradient of the heating curves changes.
Changing the level:
B
The heating curves are shifted in parallel in a verti-
cal direction.
Changing the standard room temperature (set
C
value):
The heating curves are moved along the "room
temperature set value" axis.
Heating circuit
A heating circuit is a sealed unvented circuit between
the boiler and radiators, in which the heating water cir-
culates.
A heating system may comprise several heating cir-
cuits: for example, one heating circuit for the rooms
occupied by you and one heating circuit for the rooms
of a separate apartment.
Heating circuit pump
Circulation pump for circulating the heating water in
the heating circuit
Mixer
Hot heating water from the boiler is mixed with cooled
heating water from the heating circuit. The heating
water, brought to the right temperature as required, is
pumped to the heating circuit by the heating circuit
pump. The control unit adjusts the flow temperature via
the mixer to suit different conditions, e.g. changing out-
side temperatures.
Night setback
See "Reduced heating mode"
3.5
1.4
A
B
0.2
-20
Outside temperature
in °C
Open source licences
The programming unit firmware contains open source
software components. Such software is released under
an open source licence and thus available to every-
one.
The full text of the licence can be displayed using the
menu point of the same name.
Open flue operation
The combustion air is drawn from the room where the
boiler is installed.
Room sealed operation
The combustion air is drawn from outside the building.
Room temperature
Standard room temperature:
■
For periods when you will be at home during the day,
select the standard room temperature.
■ Reduced room temperature:
For periods when you will be absent or during the
night, set the reduced room temperature; see "Heat-
ing mode".
Safety valve
A safety device that must be installed in the cold water
pipe by your heating contractor. The safety valve
opens automatically to prevent excess pressure in the
DHW cylinder.
Solar circuit pump
In conjunction with solar thermal systems.
The solar circuit pump delivers the cooled heat transfer
medium from the DHW cylinder indirect coil to the
solar collectors.
Set temperature
Default temperature that should be reached, set DHW
temperature for example.
Summer mode
Operating program "DHW only".
In warmer months, you can switch off heating mode.
The boiler remains operational for DHW heating. Cen-
tral heating is switched off.
Cylinder loading pump
Circulation pump for heating the potable water inside
the DHW cylinder
Appendix
53