Viessmann VITOTRONIC 200 Operating Instructions Manual page 63

Terminology
(cont.)
Ventilation unit function
B
C
A
E
F
Fig. 55
Supply air
A
(e.g. bedrooms, child's room, living room)
Exhaust air
B
Outdoor air
C
Extract air
D
(e.g. from the kitchen, bathroom, toilet)
Bypass closed, ventilation with heat recovery
E
Bypass active, ventilation without heat recovery
F
Ventilation with heat recovery, bypass closed
The heat extracted from the interior (extract air) is
used to preheat the air supplied to the interior (supply
air) using a heat exchanger inside the ventilation unit.
For this, bypass will be closed.
E
This means that the energy loss is very low, compared
to venting via an open window.
Ventilation without heat recovery, bypass active
With bypass active, 100 % of the extract air is
F
routed past the heat exchanger, and fresh filtered out-
door air at outside air temperature is routed into the
supply air area.
This enables cooler outdoor air to be channelled into
the interior, e.g. during cooler summer nights.
The bypass is active if the following conditions have all
been met:
The outdoor air is cooler than the indoor air:
■
The outdoor air temperature is at least 4 °C below
the room temperature.
The rooms are warmer than required:
■
The room temperature is at least 1 °C above the
"Set room temperature" for the ventilation system.
The temperature of the air supplied exceeds the min-
■
imum temperature for passive cooling ("Min supply
air t. byp").
D
Air flow
To ensure that your interior suffers neither from nega-
tive nor positive pressure, the air flow rate of the sup-
ply air must be exactly the same as that of the extract
air. These air flow rates are adjusted by your contrac-
tor during commissioning.
Control of humidity and carbon dioxide concentra-
tion (CO concentration)
2
If a CO /humidity sensor is connected to the ventilation
2
unit, the air flow rate will be automatically adjusted
subject to the actual CO
ity level in the air. However, this only applies to the
"Ventilation program" and the "Standard" operating
status.
Frost protection for the heat exchanger inside the
ventilation unit
In the heat exchanger of the ventilation unit the out-
door air is preheated by the extract air from the interior.
This cools down the extract air and water condenses
inside the heat exchanger.
At low outside temperatures, this condensate in the
heat exchanger can turn to ice.
Frost protection functions:
The outdoor air is preheated by an electric preheater
■
bank, if installed (accessory).
The air flow rate is reduced, if necessary until the fan
■
is at a complete standstill.
Note
With active frost protection, the indicated fan stage
may be other than the selected fan stage. The fan
stage display mirrors the reduced air flow rate of the
frost protection function.
Supply air heating via heating circuit HC1 (ventila-
tion heating circuit)
The heat pump can heat up the supply air if a hydraulic
reheater bank (accessory) is installed in your ventila-
tion unit. The outdoor air preheated in the heat
exchanger of the ventilation unit is then reheated by
the heat pump via the reheater bank.
In this case, set the room temperature and the time
program for central heating via the menu for heating
circuit HC1.
Note
As the ventilation heating circuit only provides a low
heating output, we recommend that the supply air
heating is only used as the sole heat source in very
well insulated buildings (e.g. passive house).
Appendix
concentration and the humid-
2
63