Viessmann VITOCROSSAL 300 Operating Instructions Manual page 43

Vitocrossal 300 CA3 Series 2.5 to 6.0 Operating
Terminology
(continued)
Example:
For outdoor temperature 5°F (-15°C):
A Underfloor heating system, slope 0.2 to 0.8
B Low temperature heating system, slope 0.8 to 1.6
C Heating system with a boiler water temperature in
excess of 167°F (75°C), slope 1.6 to 2.0
Outdoor temperature
Legend
A Changing the slope:
The gradient of the heating curves changes.
B Changing the shift:
The heating curves are shifted in parallel in a vertical
direction.
C Changing the standard room temperature (set value):
The heating curves are offset along the "Set room
temperature" axis.
Heating curve
Heating curves illustrate the relationship between the
outdoor temperature, the set room temperature and the
boiler water temperature or supply temperature.
The lower the outdoor temperature, the higher the boiler
water temperature or supply temperature.
In order to guarantee sufficient heat and minimum fuel
consumption at any outdoor temperature, the conditions
of your building and your heating system must be taken
into consideration. The heating curve is set by your
heating contractor for this purpose.
The illustrated heating curves apply with the following
settings:
H Heating curve shift = 0
H Standard room temperature (set value) = 68°F (20°C)
Heating circuit
A heating circuit is a sealed unvented circuit between the
boiler and radiators, in which the heating water circulates.
A heating system may comprise several heating circuits.
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
Mixing valve
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 supply temperature via the
mixing valve to suit different conditions, e.g. changing
outdoor temperatures.
Night setback
See "Reduced heating mode"
Open source licenses
The programming unit firmware contains open source
software components. Such software is released under
an open source licence and thus available to everyone.
The full text of the licence can be displayed using the
identically named menu point.
Additional Information
43