Viessmann Vitotronic 200 Installation And Service Instructions Manual page 80

Function description
Cylinder temperature control
Code "55:3", cylinder temperature control, cylinder primary system
The DHW cylinder goes cold (set
value 2.5 K, change via coding
address "59"):
The set boiler water temperature is
adjusted 20 K higher than the set
DHW temperature (adjustable via
coding address "60").
The cylinder primary pump starts.
The three-way mixing valve opens
and then regulates to the defaulted
set value.
The cylinder primary pump cycles
(short term ON and OFF) until the
set flow temperature has been
reached (set DHW temperature +
5 K). Then it runs constantly.
If, during cylinder heating, the
actual value stays below the
required set temperature, then the
cylinder primary pump will tempora-
rily cycle again.
80
(cont.)
The DHW cylinder is hot:
(Cylinder temperature sensor 1:
Actual value set value
and
Cylinder temperature sensor 2:
Actual value>set value 1.5 K)
The set boiler water temperature is
returned to the weather-compen-
sated set value.
The cylinder primary pump stops
immediately when the three-way
mixing valve is fully opened.
or
The cylinder primary pump stops
after expiry of the run-on time that is
selected via code "62".