NRT405F901 manual
Chapter 12
Fan control
25
Chapter 12 Fan control
Automatic fan speed control
The current fan speed is shown in the display and can be set manually to Low, Medium or
High speed. It can also be set to Auto, which means that the fan speed is controlled by the
heating and/or cooling demand, depending on the configuration.
By pressing the fan button, the fan speed is set to Low
Medium
High or
Auto.
The factory setting in the Auto position is that the fan speed is controlled at both heating and
cooling demand. The first step starts when the output signal from the controller internally
exceeds 20 % (5% if an electric heater is used). The second step starts at 60 % and the third
at 100 %. When the fan speed decreases, each fan step has a hysteresis of 5 % for changing
over to the next step. For example, the fan will change from the third to the second step when
the output signal falls below 95 %.
Manual fan speed control
By pressing the fan button, the fan speed is set to Low
Medium
High or
Auto.
When there is no heating or cooling demand in the Auto position, the fan will run at its
lowest setting. This is editable in parameter 31, enabling the fan to stop entirely when there
is no heating or cooling demand. The fan is also inactive in the Off and Window modes.
However, it will continue to run if mould protection has been configured. If the fan has been
configured not to be affected by the controller output (parameter 25), the ”Auto” option will
not be shown when pressing the fan button.
