Siemens RDF400 User Manual

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Siemens RDF300…/RDF340.../RDF400… Basic Documentation CE1P3076en
Building Technologies 4BFunctions 28 Aug 2008
4.6.3 4-pipe fan coil unit
In 4-pipe applications, the controller controls two valves in heating and cooling
mode, heating/cooling mode by manual selection, or heating and cooling mode
with changeover. Heating and cooling mode (P01=4) is factory set.
The heating or cooling output can be released via operating mode selector button if
parameter P01 is set to manual (P01=2).
The heating and cooling output is swapped per the sensor input status (see
automatic heating and cooling changeover sensor), if parameter P01 is set to
changeover (P01=3). This mode is used for “Main and Secondary” application,
which equates to a 4-pipe fan coil unit system with different capacity for heating
and cooling coils. The water circuit is changed to optimize the energy exchange
depending on the season (summer/winter).
Y
1
0
w
w
3076D15
T[°C]
Y2
Y1
Changeover
T
B1
Y2
Y1
M1
3076D23
T
B2
The diagram below shows the control sequence for on/off (2-position) control.
Heating and cooling mode (P01=04)
T[°C] Room temperature
w Room temperature setpoint
Y1 Control. command “Valve” or “Comp.” Heat
Y2 Control. command “Valve” or “Comp.” Cool
SDH Switching differential “Heating”
SDC Switching differential “Cooling”
Y
½ SDC
1
0
½ SDC
w
3076D11
T[°C]
Y2
½ SDH
½ SDH
Y1
½
x
dz
½
x
dz
X
dz
Dead zone
Heating mode with manual selection
(P1=2)
Cooling mode with manual selection
(P1=2)
½ SDH
1
0
½ SDH
w
Y
3076D01
T[°C]
Y1
Y
½ SDC
1
0
½ SDC
w
3076D13
T[°C]
Y2
Heating and cooling
4-pipe application with
manual selection
“Main and Secondary”
application (4-pipe
with changeover)
Control sequence
on/off output

Siemens RDF400 Specifications

General

Brand	Siemens
Model	RDF400
Category	Temperature Controller
Language	English