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Siemens
RXB (KNX) application library
FNC Description of functions for FC-10, FC-11, FC-12
CM110385en_05
Building Technologies
Control sequences
28 Feb 2009
8.4.2
2-pipe fan-coils with electric reheater
T
B1
YHC
Q1
D3
YR
10
3
85S
23
Y Output
signal
TR Room
temperature
SpC Effective
cooling
setpoint
SpH
Effective heating setpoint
H Heating
sequence
C Cooling
sequence
YHC Heating
valve
YR Electric
reheater
The control mode must be selected at the engineering stage:
heating only, cooling only or changeover
The electric reheater also operates with "Cooling only" and "Change-over" in cooling
mode. In this case, the heating setpoint (SpH) is used for control.
1-step
Modulating
Heating only
or c/o = Heating
OFF
YR
ON
0%
Y
100%
YHC
TR [°C]
YR
H
1 K
SpH
10
38
5D
56
YHC
0%
TR [°C]
YR, Y
100%
H
SpH
YR
10
38
5D
57
Cooling only
or c/o = Cooling
OFF
YR
ON
0%
Y
100%
YHC
TR [°C]
YR
H
1 K
SpH
SpC
C
10
35
8D
58
YHC
0%
TR [°C]
YR, Y
100%
H
SpH
SpC
YR
C
10
38
5D
59
Changeover with
disabled electric
heater
(see page 97)
100
0
TR [°C]
YHC
YHC
Y [%]
SpH
SpC
H
C
Change-over
10
38
5D
60
Further details: see sections 8.1.3 through 8.1.7.
Selection of the control
mode
Electric reheater with
cooling-only or
changeover applications