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Siemens
Room Temperature Controllers
N3057en
Building Technologies
2014-10-28
With the RDF110.2, when pressing the heating / cooling changeover button , the
controller will change from heating to cooling, or vice versa.
The minimum output on time and off time of Y11 can be adjusted from 1…10 minutes
via parameters P15 and P16. Factory setting is 1 minute. In this case, any readjustment
of the setpoint or of heating / cooling mode changeover will be used immediately for
computing the output status and output Y11 may not hold the minimum on / off time of
1 minute.
If parameter P15 or P16 is set to a level above 1 minute, the minimum on / off time of
Y11 will be maintained as set, even if the setpoint or changeover mode has been
readjusted.
Fan operation
The fan operates either in automatic mode or at the selected speed when using manual
mode. In automatic mode, the fan speed depends on the setpoint and the current room
temperature. When the room temperature reaches the setpoint, the control valve will
close and the fan switch off: Temperature-dependent fan control (see diagram below).
The individual switching differentials of the fan speeds can be adjusted via control
parameters P08 – P13.
Heating mode
Cooling mode
W
SDH
SDH
SDH2
SDH3
Valve
Fan
W
SDC
SDC3
SDC2
SDC
Valve
Fan
Y11
Y11
Temp
Temp
Temp
Temp
Q3
Q2
Q1
Q3
Q2
Q1
3058D
03
If desired, fan control can be set to ”Temperature-independent”, which means that
ventilation is always on, even within the dead zone, using at least fan speed 1. This can
be selected individually for Normal operation using parameter P21 and for Economy
(Energy saving) mode using parameter P20 (also refer to “Avoiding damage due to
moisture”).
In automatic mode, a dwelling time of 2 minutes (factory setting) is active. The fan
maintains that speed for at least 2 minutes before it switches to the next speed. This
dwelling time can be adjusted from 1…5 minutes using parameter P14.
When the fan starts from standstill, it starts with fan speed 3 for 1 second in order to
guarantee a safe fan motor start (to overcome inertia and friction).
Minimum output
on time / off time Y11
Ventilation always on
Dwelling time
Fan start
