Viessmann VITOLIGNO 300-P Service Instructions Manual page 121

Control functions
The DHW cylinder is hot:
■ The control unit checks whether the
boiler will still be required to supply
heating energy 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.
(cont.)
Accordingly, the control unit deter-
mines the burner and circulation pump
stop times 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".
Function description
121