Rehau NEA SMART 2.0 Service Manual page 22

Note:
This limitation is ignored when manual heating mode is
selected. Freeze protection is always active.
Filtered outside temperature, heating limit and hysteresis.
The information about outside temperature may come from a wireless
or wired probe which is installed outside the building. When the
system is connected to internet there is the option to use weather
service. The outside temperature is timely filtered with a time
constant, by default set to 48 h.
When the filtered outside temperature drops below the heating limit,
heating mode is started.
Relevant parameters
Web page:
Home  Installer  Settings  Heating / Cooling Settings
App:
Settings  Installer  Control parameter  Heating
Figure 4-1 shows an example of a 5-day period:
The heating limit is 15 °C during energy level NORMAL and 13 °C
during HOLIDAY / ABSENCE (see next paragraph). The hysteresis is
0,5 K.
The filtered outside temperature is displayed in the blue dotted line.
Between day and night there is a temperature difference of around 8 K,
in the early morning hours of day 1 and 2 the temperature is around
12 °C, at day it reaches more than 20 °C. The filtered outside
temperature touches the heating limit, but the integrated hysteresis
avoids start of heating mode.
In the night to day 3 there is a temperature drop down to 7 °C, the
next 2 days reach in the afternoon almost 15 °C and then even 17 °C,
but the tendency is to cooler days.
Heating mode is started in the morning of the third day.
22
25
20
15
10
Actual outside temperature
5
Filtered outside temperature
Heating mode
0
1 1,5 2 2,5 3
Fig. 4-1 Heating mode started by filtered outside temperature
Influence of energy level
The heating limit is shifted from 15 °C to 13 °C (both values are the
default settings) when all rooms, which are defined as pilot rooms, are
in absence (holiday) mode.
Influence of pilot rooms
The actual room temperature in the pilot rooms shifts the heating limit
upwards (heating mode starts earlier), as soon as one of the pilot rooms
is below his setpoint temperature. The "worst" difference to set point is
taken, in default setting each Kelvin shifts the heating limit by 1 Kelvin.
The shift is limited to +/- 3 K.
Note:
Only rooms which are too cold are considered. The
degree of this influence is determined by parameter "economy"
which can be set by the user between the minimum and
maximum values "high comfort" and "economy".
External input signals HEATING, COOLING
When the NEA SMART 2.0 system is part of a super ordinated system
– e.g. a heat pump which supplies several apartments – it must follow
the overall operation mode.
This can be done by connecting potential free switches (dry contacts)
to the digital inputs and configuring them for HEATING or COOLING.
Day
3,5 4 4,5 5 5,5 6