Interval For Long Term Average Outside Temperature - Viessmann VITOTRONIC 200 Service Instructions Manual

7002 Interval for long term average outside temperature

Averaging interval for calculating the adjusted outside
temperature (long term average).
This outside temperature is for example used for:
■ Calculating the set flow temperature from heating or
cooling curve
Changeover between central heating and central
■
cooling mode
The continuous averaging of actual temperatures
reduces the influence of brief temperature fluctuations.
The mathematical method applied acts like an attenua-
tion. With this attenuation, the adjusted outside tem-
perature achieves the following values after a sudden
temperature change:
■ 63 % of the change after a single averaging interval
■ 95 % of the change after three averaging intervals
ϑ
100%
63%
37%
AB AB
Fig. 50
A Time of the sudden temperature change
Expiry of one averaging interval
B
7003 Temperature differential for calculating the heating limit
Heating limit:
Set room temperature minus "Temperature differen-
tial for calculating the heating limit 7003".
Central heating starts automatically if the adjusted out-
side temperature (long term average, averaging inter-
val in the delivered condition 3 h) falls below the heat-
ing limit. The operating program "Heating and DHW"
must be active.
In practical use, this characteristic results not only in
an adjustment but also a delay in capturing the outside
temperature.
ϑ
Fig. 51
Outside temperature (not adjusted)
A
Adjusted outside temperature
B
Note
For other functions, the control unit calculates a short-
term average outside temperature (averaging interval
2 min).
Setting in min
t
Example:
Selected set room temperature = 20 °C
"Temperature differential for calculating the heat-
ing limit 7003" = 4 K
This results in a heating limit of 16 °C (20 °C
■ Adjusted outside temperature < 16 °C (heating limit):
Central heating starts.
Adjusted outside temperature
■
fied hysteresis of 2 K):
Central heating is stopped.
Parameter group System definition
!
A
B
t
!
18 °C (due to speci-
>
4 K).
–
197