Siemens Desigo RXB Technical Manual page 411

Two-pipe fan coil with changeover
and electric reheater
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.
Operating diagrams
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.
Siemens
Building Technologies
• 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.
YR
D4
YHC
N1
K N X
R
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.
Y
1-stage
1 K
H
ON
OFF
Y
Mod.
H
ON
YR
OFF
RXB application library (KNX)
FNC03 – Two-pipe fan coil with changeover and electric reheater
D3
Q1
T
B1
T
R1
10385D30
YHC
TR [°C]
SpH
10385D32
YHC
TR [°C]
SpH
FNC – Fancoil-Applikationen aus FC-10, FC-11, FC-12
FNC03
K NX
D1 D2
Changeover = Cooling.
In "cooling" the electric heating coil acts
as the only heating as soon as
temperature falls below SpH.
Y
ON
YR
YHC
OFF
SpH SpC
Y
H
100%
YHC
YR
0%
SpC
SpH
CM110672en_03
R
10385D31
C
TR [°C]
10385D33
C
TR [°C]
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30.11.2007