Viessmann VITOCAL 242-G Installation And Service Instructions Manual page 16

Preparing for installation
Function description of systems
The cooling capacity depends on the
heat source temperature, which itself
is subject to seasonal fluctuations.
Experience has shown that the cool-
ing capacity is higher at the beginning
of summer than at the end.
In addition, the water source tempera-
ture curve is subject to the cooling
demand of the building. Because of
large window areas or internal
sources (lighting, electrical equip-
ment), the heat source temperature
increases more rapidly during the
course of a year than it does if less
cooling is required.
DHW heating with the heat pump
In the delivered condition, domestic
hot water heating by the heat pump is
given priority in the heating circuit and
should preferably take place over-
night.
DHW heating with solar boost (only Vitocal 242)
If sufficient solar radiation is avail-
able, the DHW can be heated exclu-
sively by the solar heating system.
To optimise the solar cover, heating
the DHW cylinder by heat pump
should be limited to the upper cylinder
volume. This is achieved via an inte-
gral, manually activated three-way
diverter valve.
16
(cont.)
Underfloor heating systems and con-
crete core tempering are available for
cooling the building; radiator heating
systems are unsuitable for this pur-
pose. Ensure that any installed room
thermostats are able to be opened
manually or by servomotors when
using the cooling function.
During cylinder heating, the control
unit switches the circulation pump
OFF to prevent the cylinder heating
from being impaired.
During cylinder heating, the control
unit switches the circulation pump
OFF to prevent the cylinder heating
from being impaired.