Viessmann Vitoligno 300-P Service Instructions For Contractors page 111

Control functions
The DHW cylinder is hot:
■ The control unit checks whether the
boiler will be required to supply heat
after the cylinder has been heated up
or whether residual boiler heat should
be transferred to the DHW cylinder.
Raising the reduced room temperature
During operation with reduced room
temperature, the reduced set room tem-
perature can be automatically raised
subject to the outside temperature. The
temperature is raised in accordance with
the selected heating curve, but no higher
than the set standard room tempera-
ture.
Example using the settings in the delivered condition
90
80
70
60
50
40
30
A Heating curve for operation with
standard room temperature
(cont.)
10 5 0 -5 -10 -15
Outside temp. in °C
Accordingly, the control unit deter-
mines the burner and circulation pump
shutdown points to prevent the set
DHW temperature being substantially
exceeded after the cylinder has been
heated up.
The outside temperature limits for the
start and end of the temperature raising
can be adjusted via coding addresses
"F8" and "F9".
A
B
-20
B Heating curve for operation with
reduced room temperature
Function description
111