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Siemens
Flush-mounted Room Thermostat
CB1N3066en
Smart Infrastructure
2019-10-25
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 is
closed and the fan either remains in fan speed 1 or switches off (parameter P21,
factory setting: fan speed 1 in dead zone).
In “Temperature-dependent” fan control the fan switches off (please see diagram
below). The individual switching differentials of the fan speed 1 (Q1 only) can be
adjusted via control parameters P08 – P09. The individual switching differentials of the
fan speed 2 and 3 (Q2 and Q3) are fixed at 1K.
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
30
58
D
0
3
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 Comfort mode via parameter P21; also refer to “Avoiding
damage due to moisture” on page 3).
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 via parameter P14.
Whenever the fan starts from standstill, it starts with speed 3 for 1 second in order to
guarantee a safe fan motor starts (to overcome inertia and friction).
Error handling
When the room temperature is out of the measuring range, which means above 49 °C
or below 0 °C, the display shows the limiting temperature in flashing figures, e.g. “0 °C”
or “49 °C”.
If the current setpoint is not OFF (see parameter P03) and the thermostat is in heating
mode, when the temperature is below 0 °C, output Y11 is energized. In all other cases,
output Y11 is de-energized until the temperature returns to the measuring range, and
then the thermostat resumes Comfort mode.
Ventilation
always on
Dwelling time
Fan start
Temperature out of
range
