Heating Terminology - Viessmann VITODENS Operating Instructions Manual

Heating terminology

Setback mode (reduced heating mode)
See "Reduced heating mode".
Operating program
You define the following with the operating program:
■ Central heating and DHW heating
or
DHW heating only, no central heating
■
or
■ Only frost protection for the boiler and the DHW cyl-
inder is active.
No central heating, no DHW heating
Note
No operating program is available for central heating
without DHW heating. When central heating is needed,
hot water is generally also required (winter mode).
Operating status
In the "Heating and DHW" operating program, the
operating status changes from "Standard heating
mode" to "Reduced heating mode" and vice versa. The
times at which the operating status is changed over
are defined by you when setting the time program.
Extension kit for heating circuit with mixer
Assembly (accessories) for controlling a heating circuit
with mixer, see "Mixers"
Screed drying
Your heating contractor can activate this function for
screed drying, for example in your new build or exten-
sion. This means your screed is dried in line with a
fixed time program (temperature/time profile) that is
appropriate for the building materials used.
The screed drying function affects heating circuits with
mixer:
■ All rooms are heated according to the temperature/
time profile.
Your settings for central heating have no effect on
the duration of screed drying (max. 32 days).
DHW heating is carried out (but priority control is
■
cancelled).
Underfloor heating
Underfloor heating systems are slow, low temperature
heating systems and only respond very slowly to short
term temperature changes.
Therefore, heating to the reduced room temperature at
night and enabling "Economy mode" during short
absences do not result in significant energy savings.
Heating mode
Standard heating mode
For periods when you will be at home during the day,
heat your rooms to the standard room temperature.
Set the periods (time phases) using the time program
for central heating.
Reduced heating mode
For periods when you will be absent or during the
night, heat your rooms to the reduced room tempera-
ture. Set the periods using the time program for central
heating. With underfloor heating systems, reduced
heating mode only yields limited energy savings (see
"Underfloor heating system").
Room temperature-dependent heating mode
In room temperature-dependent mode, the flow tem-
perature is controlled according to the room tempera-
ture. More heat is made available at a lower room tem-
perature than at a higher one.
The room temperature is captured and transmitted to
the control unit by a sensor. The sensor is fitted in the
room.
The flow temperature is regulated independently of the
outside temperature.
Weather-compensated heating mode
In weather-compensated mode, the flow temperature
is controlled according to the outside temperature.
More heat is made available at a lower outside temper-
ature than at a higher one.
The outside temperature is captured and transmitted to
the control unit by a sensor. The sensor is fitted to the
exterior of the building.
Heating curve
Heating curves illustrate the relationship between the
outside temperature, the set room temperature and the
boiler water temperature or flow temperature. The
lower the outside temperature, the higher the boiler
water temperature or flow temperature.
In order to guarantee sufficient heat and minimum fuel
consumption at any outside temperature, the condi-
tions 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 heating curves shown apply with the following set-
tings:
■ Heating curve level = 0
■ Standard room temperature (set value) = 20 °C
Appendix
61