Weather-Compensated Control Unit - Viessmann Vitodens 222-F B2TA Installation And Service Instructions Manual

Function description

Weather-compensated control unit

14°C
Boiler temperature
Heating mode
The control unit determines a set boiler
water temperature subject to outside
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 temper-
ature is transferred to the burner control
unit. From the set and actual boiler water
temperatures, the burner control unit cal-
culates the modulation level and regu-
lates the burner accordingly.
Heating the DHW primary store from cold
The heating circuit pump is switched ON
and the 3-way diverter valve will be
changed over, if the cylinder tempera-
ture sensor captures a temperature
lower than the defaulted set value.
■ The cylinder primary pump is switched
ON if the boiler water temperature ≥
set DHW temperature.
■ The burner is switched ON if the boiler
water temperature ≤ set DHW temper-
ature, and the cylinder primary pump
is switched ON when the required
boiler water temperature is reached.
150
HC1
21°C
48 °C
The electronic temperature limiter inside
the burner control unit limits the boiler
water temperature.
The primary store is heated up to the set
DHW temperature. Heating stops when
the specified temperature has been
reached at the cylinder temperature sen-
sor.
After heating has ended, the cylinder pri-
mary pump and the 3-way diverter valve
remain on for a further 30 s.