Viessmann VITOTROL 300 RF Operating Instructions Manual page 48

Appendix
Terminology
Operating program
The operating program determines
whether you heat your rooms and DHW,
or only heat DHW, or whether you shut
down your heating system, thereby ena-
bling frost protection monitoring.
You can select the following operating
programs:
■ "Heating and DHW"
The rooms are heated and DHW is
provided (winter mode).
■ "Only DHW"
DHW is provided but there is no cen-
tral heating (summer mode).
■ "Standby mode"
Frost protection for the boiler and the
DHW cylinder is enabled, no central
heating, no DHW heating.
Note
No operating program is available for
central heating without DHW heating.
When you want central heating, hot
water is generally also required (winter
mode).
If you do want just central heating, select
the operating program "Heating and
DHW" and set the DHW temperature to
10 °C (see page 31). This means that
you will not heat DHW unnecessarily but
the DHW cylinder is protected against
frost.
48
(cont.)
Operating status
In the operating program "Heating and
DHW", the operating status changes
from "Standard heating mode" (see
page 49) to "reduced heating mode"
(see page 49) and vice-versa. The
times for the operating status change-
over are defined by you when setting the
time program.
Heating circuit
A heating circuit is a sealed circuit
between the boiler and radiators, in
which the heating water circulates.
A heating system may comprise several
heating circuits. For example, one heat-
ing circuit for the rooms occupied by you
and one heating circuit for the rooms of
a separate apartment.
Heating circuit pump
Circulation pump for the circulation of the
heating water in the heating circuit.
Actual temperature
Current temperature at the time of the
scan; e.g. actual DHW temperature.
Mixer
A mixer mixes the water heated in the
boiler with the cooled water returning
from the heating circuit. The water, thus
brought to the right temperature, is pum-
ped to the heating circuit by the heating
circuit pump. The control unit adjusts the
heating circuit flow temperature via the
mixer to suit different conditions, e.g.
changing outside temperatures.