Viessmann Cascade control unit Installation, Operating And Service Instructions page 20

Functions
Operating conditions
Start-up optimisation
The start-up optimisation ensures that the boiler is heated up before the
standard mode commences, subject to room and outside temperature.
This ensures that the set room temperature is achieved before the standard
mode commences. A minimum and maximum temperature can be set for the
heat-up period. The greater the difference between the set room temperature
in standard mode and the outside temperature, the longer the heat-up period.
Set value (multi-boiler control unit)
Heat-up time
minimum
Heat-up time
maximum 360 min
Room factor
heat-up 30 min/K
Outside factor
heat-up
In the "Operating details" menu (see page 15) you can scan whether the
control unit is set to "Standard mode" on account of the heat-up function.
20
(cont.)
(early heat-up)
The control unit activates at least the minimum
set period earlier.
15 min
The control unit will be activated in advance by
no more than the minimum set period.
Earlier start-up time, to raise the room
temperature by 1 K.
The outside temperature has no influence here.
Room factor correction subject to outside
temperature.
0.02 K