Viessmann Vitovalor PT2 Installation And Service Instructions For Contractors page 150

Function description
Control functions
(cont.)
The heating curve is offset along the set room temper-
ature axis. The start and stop points of the heating cir-
cuit pumps depend on the Heating limit... outside tem-
perature, heating circuit... setting.
90
A
C
-20
B
E
D
Fig. 104 Example 1: Adjusting the set room tempera-
ture from 20 to 26 °C
Flow temperature in °C
A
Outside temperature in °C
B
Set room temperature in °C
C
Heating circuit pump "Off"
D
Heating circuit pump "On"
E
Changing the set room temperature
Operating instructions
Reduced room temperature
90
A
C
-20
B
D E
Fig. 105 Example 2: Adjusting the reduced set room
temperature from 5 °C to 14 °C
A Flow temperature in °C
Outside temperature in °C
B
Set room temperature in °C
C
Heating circuit pump "Off"
D
Heating circuit pump "On"
E
Changing the reduced set room temperature
Operating instructions
Change curve and level
Individually adjustable for each heating circuit.
150
90
3.5
A
+20 -20
Outside temperature in °C
Fig. 106
Changing the slope
A
Changing the level (vertical parallel offset of the
B
heating curve)
Raising the flow temperature of the heating cir-
cuits during operation with room temperature
hook-up
The higher the value, the greater the influence of the
room temperature on the set flow temperature of the
heating circuit.
Room influence factor parameter
Heating circuit
1 (without mixer)
2 (with mixer)
3 (with mixer)
4 (with mixer)
Example for determining the increase in the flow tem-
perature using the value of the heating curve when the
actual room temperature deviates from the set room
temperature:
■ Set room temperature = 20.0 °C
■ Actual room temperature = 18.0 °C
■ Heating curve slope =1.4
■ Room influence factor = 8 (delivered condition)
Determining the increase in flow temperature
(RT set - RT actual) x (1 + slope) x room influence fac-
tor/4 = raising the flow temperature via heating curve
value
(20 - 18) x (1 + 1.4) x 8/4 = 9.6
Increase in flow temperature via heating curve value
= 9.6 K
1.4
B
0.2
Parameter
933.7 (not assigned)
934.7
935.7
936.7