15Installation Instructions VRC430 0020042468_02
Glossary
Set-back temperature
The set-back temperature is the temperature to which
your heating lowers the internal temperature to outside
the programmed time windows.
Auto_Off (expert technician level)
The "Mode_Auto_Off" menu item in screen C21, "Overall
system parameters", is used to determine how the con-
troller behaves when the timer-control is off (i.e. be-
tween the "time windows"). The options are Frost pro-
tection, ECO and set-back.
– Frost protection
In the times when no time windows are programmed,
the boiler is switched off. The frost protection func-
tion (see location) is active.
– ECO
In the times when no time windows are programmed,
the boiler is switched off. The external temperature is
monitored. If the external temperature falls below
3 °C, the target room value reverts to the set-back
temperature (minimum 5 °C). This target room value
is used as a basis. A frost protection delay time (see
location) will affect the start time here. If the external
temperature rises above 4 °C, the external tempera-
ture continues to be monitored, the boiler is switched
off.
– Set-back
In the times when no time window is programmed, the
room target temperature reverts to the set-back tem-
perature (minimum 5 °C). This target room value is
used as a basis.
Operator level
This is used to display and set/change basic parameters.
The parameters can be set/changed by an unskilled op-
erator and during normal operation. The heating system
is continuously matched to the requirements of the user
by corresponding adjustment of the fundamental pa-
rameters.
Operating level for the expert technician
It serves to display and to set/change specific parame-
ters. This level is reserved for the expert technician and
is therefore protected by an access code.
Operating mode
Operating modes "Auto" (Automatic), "Manual" and
"OFF" are available. You can specify the way in which
your room heating and water heating are controlled
using the operating modes (see operating instructions
Section 4.3.2, Table 4.2).
Frost protection function
The frost protection system protects your heating sys-
tem and your apartment from frost damage. It remains
active in the operating mode "OFF".
The frost protection function monitors the external tem-
perature. If the outside temperature drops below 3 °C,
the heating pump switches on for 10 minutes and then
off for 10 to 60 min (depends on the outside tempera-
ture). If the heating flow temperature is below 13 °C, the
burner switches on and controls the room temperature
to within 5 °C of the target room temperature. If the ex-
ternal temperature rises above 4 °C, the external tem-
perature continues to be monitored , the heating pump
and burner are switched off.
If the outside temperature drops below -20 °C, the
burner is switched on and controls the rooms tempera-
ture to within 5 °C of the target room temperature.
Frost protection delay time
By setting the frost protection delay time (expert tech-
nician level), you can delay the heating control function,
which is usually triggered by the frost-protection func-
tion (when the outside temperature is 3 °C ), for a speci-
fied time period (1 - 12 hours).
The frost protection delay setting also works in the
"ECO" function in the "Auto_Off" mode (see location).
The frost-protection delay time starts when the outside
temperature drops below 3 °C.
Heating circuit (HC1)
HC1 indicates heating circuit 1. This refers to your heat-
ing system. You can re-name HC1 to something else, if
you wish (see operating instructions Section 4.7.5).
Heating curve
The heating curve represents the relationship between
external temperature and the flowtemperature. By se-
lecting a heating curve, you can control the flow tem-
perature of your heating system and therefore also the
internal temperature.
This option allows to controller, in conjunction with the
room switch-on function (see relevant section for de-
tails), to adjust to the apartment and heating system.
Fig. G.1 shows the possible heating curves for a target
room temperature of 20 °C.
If, for example, heating curve 1.5 is selected, a flow tem-
perature of 56 °C is maintained at an external tempera-
ture of 0 °C.
Appendix
Glossary
