Two-pipe fan coil (changeover) and radiator
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).
Operating diagrams
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.
Siemens
Building Technologies
•
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.
D3
YHC
T
YH
N1
K N X
R
Y [%]
Y [%]
Change-over (Fan-Coil)
H
H
100
100
YHC
YH
0
0
SpH
SpH
Change-over
Y
H
Q34
Q24
Q14
SpH
SpC
RXB application library (KNX)
FNC18 – Two-pipe fan coil (changeover) and radiator
Q1
T
B1
T
D1
R1
Heating sequence:
C
C
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
YHC
operated in alternation, because fully open
here means 1 second ON / 1 second OFF).
Cooling sequence:
TR [°C]
TR [°C]
SpC
SpC
Control of heating/cooling valve.
C
TR [°C]
FNC – Fancoil-Applikationen aus FC-10, FC-11, FC-12
FNC18
K NX
B2
T
D2
CM110672en_03
30.11.2007
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