System configuration
Cooling via
1 heating/cooling circuit 1 heating/cooling circuit
or
1 separate cooling cir-
cuit
Max. 3 heating/cooling
circuits simultaneously
Without buffer cylinder
—
X
—
With heating water buffer cylinder
—
X
—
With heating water/coolant buffer cylinder
—
—
X
Heat pump compact appliance with installation kit with
mixer
X
—
—
Since a heating water buffer cylinder is not suitable for coolant, for
central cooling this buffer cylinder needs to be bypassed by means
of a hydraulic bypass circuit.
A heating water/coolant buffer cylinder can store both heating water
and coolant. As a result,
all
connected heating/cooling circuits can
also be supplied with coolant.
Note
The minimum flow rate and minimum system volume must be
ensured also during cooling mode. Systems
without
heating water/
coolant buffer cylinders require an overflow valve in the heating/cool-
ing circuit for this purpose.
For detailed information on system examples with central cooling:
Cooling circuits
Cooling is possible either by means of a heating/cooling circuit (e.g.
underfloor heating circuit) or a separate cooling circuit, e.g. a fan
convector. Suitable thermostatic valves must be used for cooling via
an underfloor heating circuit. Ensure that the thermostatic valves can
be opened via the AC signal or manually to enable cooling operation
during the cooling period. Radiators, panel radiators and similar are
not suitable for cooling mode.
To prevent the formation of condensate, all visible components e.g.
pipes, pumps, etc. must be thermally insulated with vapour diffusion-
proof material.
Note
For cooling mode in the following cases, a room temperature sensor
must be installed and enabled:
■ Weather-compensated cooling mode with room influence or room
temperature-dependent cooling mode via an underfloor heating
circuit
■ Cooling mode via a separate cooling circuit, e.g. fan convector
Weather-compensated cooling mode
In weather-compensated cooling mode, the set flow temperature is
calculated from the relevant set room temperature and the current
outside temperature (long term average) according to the cooling
curve. Its level and slope are adjustable.
Room temperature-dependent cooling mode
The set flow temperature is calculated from the differential of the set
room temperature and the actual room temperature.
Cooling with an underfloor heating system
The underfloor heating system can be used for heating and for cool-
ing buildings and rooms.
Surface temperature limits must be maintained to observe comfort
criteria and to prevent condensation. Therefore, the surface temper-
ature of an underfloor heating system in cooling mode must not fall
below 20 °C.
To prevent the formation of condensate on the surface of underfloor
heating systems, install a contact humidistat (accessories) into the
underfloor heating system flow. This safely prevents the formation of
condensate, even if weather conditions change quite rapidly (e.g.
during a thunderstorm).
The underfloor heating system should be sized in accordance with a
flow/return temperature pair of approx. 14/18 °C.
The following table can be used to estimate the possible cooling
capacity of an underfloor heating system.
The following applies in general:
The minimum flow temperature for cooling with an underfloor heating
system and the minimum surface temperature are subject to the pre-
vailing climatic conditions in the room (air temperature and relative
humidity). These conditions must therefore also be taken into con-
sideration during the engineering stage.
Estimated cooling capacity of an underfloor heating system depending on the floor covering and pipe spacing (assumed flow tem-
perature approx. 16 °C, return temperature approx. 20 °C)
Floor covering
Tiles
Carpet
Spacing
mm
75
150
300
75
150
300
Cooling capacity with pipe diameter
–10 mm
W/m
2
40
31
20
27
23
17
–17 mm
W/m
2
41
33
22
28
24
18
–25 mm
W/m
2
43
36
25
29
26
20
Details accurate for
Room temperature
26 °C
Relative humidity
50 %
Dew point temperature 15 °C
7.15 Connecting a solar thermal system
In conjunction with a solar control unit, a solar thermal system can
be controlled for DHW heating, central heating backup and swim-
ming pool heating. The heat-up priority can be selected individually
at the heat pump control unit.
The heat pump control unit enables certain values to be checked.
When there is a high level of insolation, all heat consumers can be
heated to a higher set value, thereby raising the solar coverage. All
solar temperatures and set values can be scanned and adjusted via
the control unit.
Design information
(cont.)
128
VIESMANN
VITOCAL
7
5831388
