Manual Corrigo E Ventilation, revision M
Chapter 5
Functional description
36
5.1.6 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. The
outdoor sensor can be placed in the fresh air inlet duct.
Free cooling is only activated when all the start conditions are fulfilled.
Start conditions:
Less than 4 days have passed since the unit was last in running mode.
The outdoor temperature during the previous running period exceeded a set limit (22°C).
It is between 00:00 and 07:00:00 in the day (settable).
The timer outputs for normal speed, Extended running normal and External stop are Off.
A timer channel will be On sometime during the recently started 24 hours.
If the outdoor sensor is located in the fresh air inlet duct and/or an extract air sensor is selected and
ALL the start conditions are fulfilled, free cooling is activated and will run for 3 minutes to ensure
that the temperature measurement when using an extract air sensor reflects the corresponding room
temperature and that the outdoor temperature sensor senses the outdoor temperature even if it is
placed in the fresh air inlet duct. If the outdoor sensor is not located in the fresh air inlet duct and a
room sensor has been selected, the unit will not start free cooling as long as all the temperatures are
not within the start and stop temperature intervals.
After 3 minutes, the stop conditions will be controlled.
Stop conditions:
Outdoor temp above the set max value (18°C) or below the set min value (condensation
risk, 10°C).
The room temp/extract air temp is below the set stop value (18°C).
One of the timer outputs for normal speed, External stop or Extended running normal is
On.
It is past 07:00:00 in the day.
If any stop condition is fulfilled after 3 minutes, the unit will stop again. Otherwise, operation will
continue until a stop condition is fulfilled.
When free cooling is active, the fans run at normal speed or the set value for pressure/flow control
and the digital output Free cooling is active. The outputs Y1-Heating, Y2-Heat exchanger and Y3-
Cooling are shut down. After free cooling has been activated, the heating output is blocked for 60
minutes (configurable time).
Inputs and outputs
AI
Outdoor temperature sensor
AI
Room sensor
or
Exhaust air sensor
DO
Free cooling
