Variants; Connection - ABB i-bus EIB Product Manual

®
ABB i-bus EIB / KNX
3.4.4

Variants

3.4.5

Connection

© 2004 ABB STOTZ-KONTAKT GmbH
Application and planning
Pipe systems
A fan coil unit can be designed as a 4-pipe, 3-pipe or 2-pipe version.
Fig. 10: Pipe systems of fan coil units
In the 4-pipe version, separate water circulation loops are used for hot and
cold water. There are thus also two separate heat exchangers for heating
and cooling which are each triggered via a valve.
The 3-pipe version functions in a similar way to the 4-pipe version. It also
has a separate inlet for hot and cold water as well as two separate heat
exchangers, each with a valve. In contrast to the 4-pipe version, the 3-pipe
version has a common return flow for hot and cold water.
The 2-pipe version consists of a single water circulation loop, via which the
room is either heated or cooled depending on the time of year. In a 2-pipe
fan coil unit, there is only one heat exchanger and one valve.
In many HVAC systems, only cooling is carried out via a 2-pipe fan coil unit.
The heating function is implemented by a conventional heater or by an
electric heater in the fan coil unit.
Room Controller
M1
SA/M 2.6.1 SA/M 2.6.1
M2
SA/M 2.6.1
M3
SA/M 2.6.1
Fig. 11: Connection of a fan coil unit (example)
4-pipe version
3-pipe version
2-pipe version
Output A = Master
Fan motor
A A
Stufe 1
B
Stufe 2
Stufe 3
A
Valve
B
(Heating)
Valve
A
(Cooling)
B
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