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Siemens
RXB application library (KNX)
FNC – Fancoil-Applikationen aus FC-10, FC-11, FC-12 CM110672en_0
3
Building Technologies
FNC03 – Two-pipe fan coil with changeover and electric reheater
30.11.2007
FNC03
Two-pipe fan coil with changeover
and electric reheater
KNX
R
•
Heating only (with LTHW), cooling only (with CHW) or changeover.
•
Changeover signal via KNX bus.
•
Modulating control of heating/cooling valve.
•
Automatic or manual fan control.
Plant diagram
N1 Room
controller.
R1
Room unit with temp.
sensor.
B1
Return air sensor.
D1 Window
switch.
D2 Presence
detector.
D3
Safety thermostat, electric
heating coil.
D4
Changeover signal via KNX
bus.
Q1
Fan (1 ... 3 speeds).
YHC Heating/cooling
valve.
YR Electric
reheater.
103
8
5S
11
T
B1
Q1
N1
R1
D1
D2
T
YHC
D4
YR
D3
KNX
R
Operating diagrams
Changeover = Heating.
In "Heating" mode, the electric heating coil
operates as a reheater for LTHW heating, i.e.
only when the valve is fully open.
Changeover = Cooling.
In "cooling" the electric heating coil acts
as the only heating as soon as
temperature falls below SpH.
1-stage
OFF
TR [°C]
Y
ON
YR
H
10385D30
1 K
YHC
SpH
OFF
TR [°C]
ON
10385D31
SpH
YR
SpC
YHC
Y
C
Y Output
signal.
TR Room
temperature.
SpH
Effective heating setpoint.
SpC Effective
cooling
setpoint.
H Heating
sequence.
C Cooling
sequence.
YHC Heating/cooling
valve.
YR
Contactor or solid state
relay for electric heating
coil.
Mod.
OFF
TR [°C]
ON
H
10385D32
YHC
SpH
YR
Y
0%
TR [°C]
100%
H
10385D33
SpH
YR
Y
SpC
YHC
C