Information for the specialist
3.4 Fan control
3.4.1
Fan levels
Frequency controlled fans, EC-fans or fans with 2-step control work with the Optigo
Ardo
. The fan can be set
to
Low, Normal or High
speed. The selection of the fan speed defines which time channel will be active in the
application.
The fans will always start directly with the desired speed.
The extract air fan and the supply air fan have individual start and stop delays which are normally set so that
the extract air fan is started before the supply air fan. If there are not enough digital outputs for individual
control, both fans will have to be started using the signal for the supply air fan, and the delay will be created
using an external time relay.
3.5 CO
2
control
In applications with varying occupancy the fan speeds or mixing dampers can be controlled by the air quality
as measured by a CO
2
sensor.
With the CO
2
function it’s possible to start and stop the fans, compensate the fan speed and in combination
with mixing damper let in more outdoor air depending on the CO
2
value. This can be configured with the
CO
2
control settings.
Table 3-10 CO
2
control settings
Fan stop/start function
When the function is activated with start/stop function and the CO
2
value rises above settable
start value the fans will start at configured speed (default: normal speed), if they are not
already running.
Mixing damper function
If demand controlled ventilation is activated in combination with mixing dampers, and the
CO
2
-value rises above the setpoint value the dampers controlled by a sequence with CO
2
function will be overtaken by the CO
2
controller and let in more outdoor air. The function is
controlled by a PI-controller.
Fan start/stop + mixing damper
If demand controlled ventilation is activated in combination with mixing dampers, and the
CO
2
-value rises above the setpoint value the dampers controlled by a sequence with CO
2
function will be overtaken by the CO
2
controller and let in more outdoor air. The function is
controlled by a PI-controller.
3.6 Free cooling
This function is used during the summer to cool the building night-time using cool outdoor air, thereby
reducing the need for cooling during the day and saving energy.
Free cooling requires an outdoor sensor and either a room sensor or an extract air sensor.
Free cooling is only activated when all the start conditions below are fulfilled.
✓
It is between 00:00 and 07:00 in the day (settable).
✓
The timer outputs for
Normal
speed,
Extended running, Normal
and
External switch
are
Off
.
✓
A timer channel will be
On
sometime during the next 24 hours.
If an extract air sensor is selected and ALL the start conditions are fulfilled, free cooling is activated and will
run for 3 minutes (settable) to ensure that the temperature measurement when using an extract air sensor
reflects the corresponding room temperature.
If a room sensor is selected, the unit will not start free cooling as long as all the temperatures are not within
the start and stop temperature intervals.
28 (76)
Optigo
Ardo
manual, Rev. A
