Additional Functions - Siemens RDG400KN Basic Documentation

Air heating / cooling
changeover
K NX
R
Supply air temperature
Water heating / cooling
changeover
K NX
R
Heating/cooling
changeover
Automatic heating /
cooling changeover via
changeover sensor
Siemens
Building Technologies
3.5

Additional functions

The supply air temperature sent by the primary controller indicates whether cool or
warm air is supplied.
The controller determines the necessity to open or close the air damper according
to the supply air temperature, the room temperature setpoint and the current room
temperature.
If no Supply air temperature is available via bus, then the air changeover is cooling
per default.
With application "Single duct", the changeover can also be accomplished via a
local multifunctional input X1/D1 (parameter P38, P42).
Only one input source must be used, either local input X1 / D1 or KNX, and
parameter "control sequence" must be set to automatic heating / cooling
changeover (parameter P01 = 3).
Functionality of the local changeover input see below.
See also section 3.8 "Multifunctional input".
With application "Single duct with heating / cooling coil", changeover information of
the heating / cooling coil can be received either via bus or via local multifunctional
input X1/D1 (parameter P38, P42).
Only one input source must be used, either local input X1/D1 or KNX and
parameter "control sequence" must be set to automatic heating / cooling
changeover (parameter P01 = 3).
See also section 3.8 "Multifunctional input".
In the absence of the required heating/cooling information from the bus (e.g. due to
problems with data communication, power failure, etc.), the thermostat operates in
the last valid operating mode (heating or cooling).
If a cable temperature sensor (QAH11.1 + ARG86.3) is connected to X1, and
parameter P38 is = 2, the water or supply air temperature acquired by the sensor is
used to change over from heating to cooling mode, or vice versa. When the water /
air temperature is above 28 °C (parameter P37), the thermostat changes over to
heating mode, and to cooling mode when below 16 °C (parameter P36).
If the water / air temperature is between the 2 changeover points immediately after
power-up, the thermostat starts in heating mode.
The water / air temperature is acquired at 30-second intervals and the operating
state is updated accordingly.
M
16 28
M Operating mode
T Water temperature
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RDG400KN Basic documentation
Functions
T [°C]
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Cooling mode
Heating mode
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CE1P3192en
20 Jul 2010