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Siemens
RXB application library (KNX)
FNC – Fancoil-Applikationen aus FC-10, FC-11, FC-12 CM110672en_0
3
Building Technologies
FNC18 – Two-pipe fan coil (changeover) and radiator
30.11.2007
FNC18
Two-pipe fan coil (changeover) and radiator
KNX
R
•
Heating/cooling coil: heating only (with LTHW), cooling only (with CHW) or
changeover.
•
Changeover signal via KNX bus.
•
Outside air temperature sensor via KNX bus.
•
Heating with LTHW radiator.
•
Downdraft compensation
•
Modulating control of heating/cooling valve and radiator valve.
•
Automatic or manual fan control.
Plant diagram
N1 Room
controller.
R1
Room unit with temp.
sensor.
B1
Return air sensor.
B2
Outside temp. via KNX bus.
D1 Window
switch.
D2 Presence
detector.
D3
Changeover signal via KNX
bus.
Q1
Fan (1… 3-speed).
YH
Heating valve (radiator).
YHC Heating/cooling valve (fan
coil).
1038
5S
2
1
B1
YHC
Q1
N1
R1
D1
D2
T
YH
T
D3
B2
T
T
KNX
R
Operating diagrams
100
0
TR [°C]
Y [%]
SpH
SpC
YH
H
C
100
0
TR [°C]
Y [%]
SpH
SpC
Change-over (Fan-Coil)
YHC
H
C
10
38
5D
5
0
YHC
Heating sequence:
The heating coil in the fan coil system operates
in sequence with the radiator, i.e. the
heating/cooling valve is only operated after the
radiator valve is fully open
(thermal valves are
operated in alternation, because fully open
here means 1 second ON / 1 second OFF).
Cooling sequence:
Control of heating/cooling valve.
Y Output
signal.
TR Room
temperature.
SpH Effective heating setpoint.
SpC Effective cooling setpoint.
H Heating
sequence.
C Cooling
sequence.
YH
Heating valve (radiator).
YHC Heating/cooling valve (fan
coil).
Q14 Fan speed 1.
Q24 Fan speed 2.
Q34 Fan speed 3.
10
38
5D
5
1
Change-over
TR [°C]
Y
H
C
Q14
Q24
Q34
SpH
SpC