17
4.5
Free cooling
This function is used during the warm period to save energy by using cold outdoor air, e.g. during night time, to cool
down the building.
Note:
The following is only valid if the free cooling function is set to Active in the program menu.
In order for the free cooling function to work, a total of 3 temperature sensors (outdoor, supply and extract/
room) are required.
Free cooling is only activated when the following starting conditions are met.
Starting 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 time channel will be On sometime during the recently started 24 hours.
The unit checks the night temperature (indoor and outdoor temperature) during 3 minutes at the set starting hour when
the fans are started so that the sensors can perform a temperature measurement.
If above conditions are met the free cooling function is started, if not the unit goes back to OFF position.
If the outdoor sensor is not located in the outdoor 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.
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
• The time has past 07:00:00.
When free cooling is active, the fans run at normal speed or the set value for pressure/flow control and the digital out-
put Free cooling is active. The outputs Y1-Heating and Y3-Cooling are shut down. After free cooling has been activated,
the heating output is blocked for 60 minutes (configurable).
5
Maintenance
Danger
• Make sure that the mains power supply to the unit is disconnected before performing any maintenance
or electrical work!
• All electrical connections must be carried out by an authorized installer and in accordance with local rules
and regulations.
Warning
In order to avoid electrical shock, fire or other damage that might occur in connection with faulty use and
operation of the unit, it is important to consider the following:
• The system must be installed according to the installation instructions.
• Insulate mains power supply before service or cleaning of the heat recovery unit.
• Make sure the filter is mounted in its place before running the system.
• Maintenance must be performed according to the instructions.
Caution
Make sure that loosened parts during maintenance doesn’t fall down and causing injury.
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Summary of Contents for Topvex SF02-S12
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