Viessmann Vitotronic 200 Installation And Service Instructions For Contractors page 113

Control of the heating circuits
Flow temperature control
110
A
80
D
8 K
+20
Outside temperature in °C
Fig. 47
Maximum boiler water temperature limit (parame-
A
ter "06" in the "Boiler" group)
Slope = 1.8 for heating circuit without mixer
B
Slope = 1.2 for heating circuit with mixer
C
Boiler water temperature (at differential tempera-
D
ture = 8 K)
Lower boiler water temperature
E
Differential temperature:
■ The differential temperature can be set in parameter
"0C" in the "General" group.
■ Delivered condition 8 K.
■ The differential temperature is the minimum value by
which the boiler water temperature should be higher
than the highest currently required flow temperature
of the heating circuit with mixer.
(cont.)
System with only one heating circuit with mixer:
■
The boiler water temperature is regulated automati-
cally to 8 K above the set flow temperature of the
heating circuit with mixer.
■ System with heating circuit without mixer and heating
B
circuits with mixer:
The boiler water temperature operates in accordance
with its own heating curve. The differential tempera-
ture of 8 K towards the set flow temperature of the
heating circuits with mixer is set at the factory.
C
Raising the reduced room temperature
E
During operation at reduced room temperature, the
reduced set room temperature can be automatically
raised subject to the outside temperature. The temper-
-20
ature is raised in accordance with the selected heating
curve, and no higher than the standard set room tem-
perature.
The outside temperature limits for the start and end of
temperature raising can be set in parameters "25" and
"26" in the "Heating circuit..." group.
Function description
113