Viessmann VITODENS 333-F WS3A, Service Instructions Manual

Page: 92 / 124

Heating the DHW primary cylinder from cold
The heating circuit pump is switched
ON and the three-way diverter valve
will be changed over, if the cylinder
primary temperature sensor captures
a temperature lower than the set tem-
perature.
&
The DHW primary pump is switched
on if the boiler water temperature
≥
set DHW temperature.
&
The burner is switched on if the boil-
er water temperature
≤ set DHW
temperature, and the DHW primary
pump is switched on when the
required boiler water temperature is
reached.
The cylinder is then heated up to the
set DHW temperature. Heating stops
when the set temperature has been
reached at the cylinder temperature
sensor and at the outlet temperature
sensor.
After heating, the cylinder primary
pump and the three-way diverter
valve remain ON for a further 30 s.
Boosting when DHW is drawn off
When DHW is drawn off, cold water
enters at the bottom of the cylinder.
The heating circuit pump is switched
ON and the three-way diverter valve
is activated, if the cylinder tempera-
ture sensor recognises a temperature
lower than the set temperature.
&
The DHW primary pump is switched
on if the boiler water temperature
≥
set DHW temperature.
&
The burner is switched on if the boil-
er water temperature
≤ set DHW
temperature, and the DHW primary
pump is switched on when the
required boiler water temperature is
reached.
The DHW is controlled to the specified
temperature via the cylinder tempera-
ture sensor.
The cylinder continues to be heated
up after the draw off process has
ceased, until the set DHW tempera-
ture has been reached at the cylinder
temperature sensor.
The cylinder primary pump and the
three-way diverter valve remain ON
for a further 30 s.
Constant temperature control unit
(cont.)
92
Function description
5692
731
GB