Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 159

Heating circuit control
Time programs
For central heating, up to 3 changes per
day between standard and reduced
room temperature can be programmed
(3 time phases).
Heating curve
The heating curve must be adjusted to
adapt the control unit to the building and
the heating system. The heating curve
characteristics determine the set boiler
water temperature subject to outside
temperature. For more information on
adjusting the heating curve, see
page 81.
Adjustment is based on the average out-
side temperature which is made up of the
actual and adjusted outside tempera-
ture.
Summer/winter heating limit
Coding addresses: 730, 1030, 1330
Heating mode is switched on or off
according to the weather conditions over
the course of the year.
Flow temperature control
The boiler water temperature is control-
led via a differential temperature (deliv-
ered condition 8 K) above the required
flow temperature.
The differential temperature can be
selected via coding addresses 830, 1130
and 1430.
The flow temperature is limited:
(cont.)
At the factory, time phase 1 is set for
every day from 06:00 to 22:00 h, i.e. dur-
ing that time, rooms are heated to the
standard room temperature.
The heating circuit (heating circuit pump)
is automatically switched off when the
outside temperature exceeds the set
value. This function is subject to the
adjusted outside temperature.
Daytime heating limit
Coding addresses: 732, 1032, 1332
Heating mode is switched on or off
according to the outside temperature
over the course of the day.
The heating circuit (heating circuit pump)
is automatically switched off when the
actual outside temperature exceeds the
set comfort level minus the set differen-
tial (daytime heating limit). ECO appears
in the remote control unit display.
■ at the upper end by the electronic max-
imum temperature limit.
Setting range 8 to 95 °C (coding
addresses 741, 1041, 1341).
■ at the lower end by the electronic min-
imum temperature limit.
Setting range 8 to 95 °C (coding
addresses 740, 1040, 1340).
Function description
159