Page 65 - Advanced Course
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KNX ADVANCED COURSE
3.1.2 Design Variants
Fan coil units are available in different versions. Their mode of operation is shown below:
4-pipe system
If a room should be cooled, the control valve on the cooling circuit (blue) is opened and
the carrier medium can circulate through the battery. The fan starts running in parallel and
begins to blow air through the battery. The air is then let in via the corresponding
temperature exchange and directed into the room.
The system behaves in a similar way in heating mode. The “cooling” control valve is
closed and the “heating” control valve is opened. The other medium then circulates
through the heater battery (red) and the air that is flowing through is heated.
There are therefore two fully independent circuits.
Controller
Figure 40: Structure of the 4-pipe FCU version
Home and Building Management Systems KNX Association
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