Viessmann Vitodens 200 Service Instructions Manual page 88

Function description
Weather-compensated control unit
b/a Setting values
d Confirmation
Heating mode
The control unit determines a set boil-
er water temperature subject to out-
side temperature or room temperature
(if a room temperature-dependent
remote control is connected) and to
the slope/level of the heating curve.
The determined set boiler water tem-
perature is transferred to the burner
control unit. From the set and actual
boiler water temperatures, the burner
control unit calculates the modulation
level and regulates the burner accord-
ingly.
DHW heating
The burner, the circulation pump and
the three-way valve are started or
changed over, if the cylinder tempera-
ture lies 2.5 K below the set cylinder
temperature.
Boosting DHW heating
The booster heating function is acti-
vated if a switching period is selected
for the fourth time phase. This period
must lie outside the switching times
for normal DHW heating to enable the
control unit to recognise the signal.
88
(cont.)
c Information
e Standard settings (Reset)
The boiler water temperature will be
limited:
To 74 °C by the control thermostat
inside the burner control unit.
To 82 °C by the electronic tempera-
ture limiter inside the burner control
unit.
To 100 °C by the temperature limiter
in the safety chain (interlocks the
burner control unit).
The set boiler water temperature is
adjusted 20 K higher than the set
DHW temperature (adjustable via
coding address "60"). The burner will
be switched OFF and the circulation
pump run-on time will begin, if the
actual cylinder temperature exceeds
the set cylinder temperature by 2.5 K.
The set temperature value for the
heating boost is adjustable in coding
address "58".