Minimum On Time; Fan Overrun Time (Switch-Off Delay); Periodic Fan Kick - Siemens Desigo RXB Technical Manual

Parameter
Fan control
Auto
Manual
Fan startup behavior
Notes
Return air sensor
Siemens
Building Technologies
Description
Fan speeds are changed over automatically
(by the room controller). Manual fan speed presetting is possible only
in operating state Comfort.
No automatic fan control. For example, the fan is operated manually
on the fan coil itself and can be enabled via relay Q14 (relay Q14 is
ON in Comfort mode).
The motors of some fans do not have a sufficiently powerful torque to set the fan in
motion at the lowest speed. Multi-speed fans are, therefore, always started at the
highest speed and then switched back to fan speed 1.
• This feature also applies to manual fan-speed control via the room unit.
• The unused relay outputs are freely available for other purposes (see page 136)
9.2.2

Minimum on time

Each fan speed remains on for a pre-defined minimum period before switching to the
next higher speed. This enables the controller to adjust to the fan speed
9.2.3

Fan overrun time (switch-off delay)

When switching off an electric reheater (FNC03, FNC05), it is essential to ensure that
the residual heat from the electric heater battery is dissipated.
For this reason, the fan is switched off only after a delay. The overrun time can be
defined.
9.2.4

Periodic fan kick

If the room temperature is measured with a return air sensor in the fan coil (connected
to input B1 at the room controller, see Section 7), the fan must be switched on to
ensure that the effective room temperature is measured correctly.
The function "Periodic fan kick" is used for this purpose.
From version V2.36, a reduced functionality (without time values for Comfort and
Economy ) is available even if no return air sensor is parameterized.
Note! For tool architecture reasons, those time values are visible and settable in ACS
and in the HandyTool although not supported by the controller.
RXB (KNX) application library
Fan control
FNC Description of functions for FC-10, FC-11, FC-12
HandyTool
1
0
115/166
CM110385en_05
28 Feb 2009