Glossary
Installation instructions VRC 470f 0020124645_00 51
15
If heating curve 0.4 is selected and 21 °C rather than
20 °C is specified as the target room temperature, the
heating curve is displaced as shown in Fig. 2. The heat-
ing curve is displaced according to the value of the room
target temperature along axis a which is angled at 45°.
This means that when the outside temperature is -15 °C,
the control provides a flow temperature of 45 °C.
Heating flow temperature
The boiler heats water which is then pumped through
the heating installation. The temperature of this hot
water as it leaves the boiler is referred to as the flow
temperature.
HK2
HK2 refers to heating circuit 2, which is additional to the
appliance’s internal circulation system, heating circuit1.
In other words, it refers to the first heating circuit in the
heating system.
Hot water production
The boiler heats the water in the domestic hot water cyl-
inder to the selected target temperature. If the tempera-
ture in the domestic hot water cylinder falls by specific
amount, the water is heated up again to the target tem-
perature. You can set time periods for heating up the
contents of the cylinder.
Legionella
Legionella are water-borne bacteria which can quickly
propagate and cause serious lung diseases. They occur
wherever heated water provides the optimum conditions
for multiplication. Temporarily heating the water to
above 60 °C kills off the legionella.
Mode
With the modes, you determine how the heating system
or hot water production is controlled, e.g. in automatic
mode or manually.
Room temperature
The room temperature is the temperature actually
measured in the dwelling.
Room temperature control
In menu page C8 “HK1 Parameter” you define under
option “Room temp control” if you are going to use the
integrated temperature sensor in the controller or in the
remote control unit. A prerequisite is that the controller
is wall-mounted or the VR 81/2 remote control unit is
connected.
Set-back temperature
The set-back temperature is the temperature to which
your heating system reduces the room temperature out-
side set period.
Soft key function
The function of the function keys switches depending on
the menu you are currently in.
The current functions of the function keys are
displayed in the bottom display lines.
Target room temperature (Desired temperature)
The target room temperature is the temperature that
you would like in the dwelling and which is specified to
the controller. The boiler continues to provide heat until
the room temperature is equal to the target room tem-
perature. The target room temperature serves as a
guideline for regulating the flow temperature according
to the heating curve.
Target values
Target values are desired values that you specify in the
controller, e.g. the target room temperature or target
temperature for hot water production.
Time periods
Three time periods per day can be set for the heating,
hot water production and circulation pump.
Example:
Period 1: Mon 09.00 - 12.00 hrs.
Period 2: Mon 15.00 - 18.30 hrs.
In the heating, each period is allocated a target value,
which the heating system maintains during this time.
For hot water generation, the target hot water tempera-
ture prevails for all time periods.
In the case of the circulation pump the time periods
determine the operating times.
In automatic mode the system is controlled according to
the time period settings.
Weather-compensated
The outside temperature is measured by a separate sen-
sor which is mounted in the open air, and the results are
transmitted to the controller. At low outside tempera-
tures the controller provides increased heating output;
at higher outside temperatures the heating output is
reduced.
