Viessmann VITOTRONIC 100 GC1 Installation And Service Instructions Manual page 107

DHW Tank Temperature Control
Control sequence
DHW tank temperature falls
(Set-point value –2.5°C / - 4.5°F,
selectable via coding address "59")
The set-point boiler water temperature
is set 20°C / 36°F higher than the
DHW temperature set-point value
(selectable via coding address "60").
The DHW pump is switched on
immediately (Coding "61: 1").
Boiler temperature-dependent switching
of the DHW pump
(Coding "61: 0"):
The circulation pump is switched on
when the boiler water temperature is
7°C / 13°F higher than the domestic
hot water temperature.
(continued)
DHW tank temperature rises
(Set-point value +2.5°C / 4.5°F)
The boiler water temperature set-point
value is reset to the value
determined by the set-point supply
temperature of the boiler circuit.
When the DHW tank has been
heated up, the DHW pump continues
to run (coding "62: 10") until
- the temperature difference
between the boiler water and
domestic hot water is less than
7°C / 13°F or
- the set-point boiler water
temperature selected through the
set-point supply temperature of the
boiler circuit is reached
or
- the set-point domestic hot water
temperature is exceeded by
5°C / 9°F.
The max. run-on time is 15 minutes
(selectable via coding address "62").
DHW pump without run-on time
(Coding "62: 00"):
The circulation pump is switched off
immediately.
With adaptive DHW tank heating
(Coding "55: 1"):
Adaptive DHW tank heating takes
into account the rate at which the
temperature increases during
domestic hot water heating.
It also takes into account whether
the boiler must supply heat for space
heating purposes after heating up the
DHW tank or whether the residual
heat of the boiler should be
transferred to the DHW tank.
The control unit determines the
switch-off time of the burner and the
circulation pump accordingly so that
the set-point domestic hot water
temperature is not substantially
exceeded after DHW tank heating is
completed.
Functional description
107