Operation; 2�1 Basic Functions; 2�1�1 Fans; 2�1�2 Temperature - Swegon CASA r85 Installation, Operation And Maintenance Manual

2. Operation

2.1 Basic functions
How to activate and set the functions is described in Section
3, Application.
2.1.1 Fans
The fans can be controlled to different operation modes from
a control panel or a Premium cooker hood�
• Away = a low airflow, which can be used when no one is
present in the home�
• Home = normal airflow�
• Boost = a high airflow, used in connection with cooking,
taking a sauna bath, drying laundry and similar activities�
The Away/Home operating modes can be controlled with the
ventilation unit's built-in weekly timer; however the operating
mode can always be changed from the Premium control panel
or a Premium cooker hood�
The airflow boost time is selected manually to 30, 60 or 120
minutes from a Premium control panel� When the unit is con-
trolled from a Premium cooker hood, the fan's boost time is 60
minutes and the time that the damper is open can be selected
to 30, 60 or 120 minutes�
2.1.2 Temperature
A rotary heat exchanger collects heat energy from the extract
air and transfers it to the supply air� When the heating output
of the heat exchanger is not enough, the following takes
place:
1) The ventilation unit is equipped with provision for measur-
ing the supply air temperature� If the supply air temperature
downstream of the heat exchanger drops below the setting
value (factory setting: +14 ºC, supply air temperature down-
stream of the fan: + 15 ºC), the controller reduces the speed
of the supply air fan and the supply air temperature then rises�
2) If the supply air temperature drops further, while the pro-
tective function described in Item 1 is activated, the supply air
fan is switched off�
3) Reheat (optional equipment)
The user sets a supply air temperature of his or her choice,
normally +13–20 ºC� This is the supply air temperatures setting
value, which the ventilation unit strives to achieve by means of
reheat and by switching on the electrically heated air heater�
The summer night cooling function can be used for so-called
free cooling� This function utilises the cool outdoor air at
night to cool down the home� When heat recovery is not
needed, an automatic summer function stops the rotary heat
exchanger� When the indoor air is colder than the outdoor air,
the rotary heat exchanger is started for "the recovery of coo-
ing energy"� (The limit values can be adjusted from a Premium
control panel�)
2.1.3 Protective functions
The electric air heater has two protective functions�
• The excess temperature (thermal overload) protection
switches off the heater, if the temperature exceeds 50 °C�
The protection automatically resets itself when the heater
has cooled down�
• The excess temperature protection switches off the heater,
if the temperature exceeds 90 °C� The protection must be
manually reset by pressing a push button on the heater�
• Temperature sensor T2 for the supply air transmits a signal
to the controller to immediately reduce the fan speed if the
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air becomes too cool, according to the description in the
Item entitled "Temperature" (protects against moisture con-
densing on the exterior surface of the supply air duct)�
The heat exchanger is equipped with an freeze protection�
When the weather is cold, there is risk freezing inside the heat
exchanger� To counteract this, the controller reduces the speed
of the supply air fan� This protective function automatically
resets itself when the temperature increases�
The fans have a thermal overload cutout, which stops them
if the temperature rises too high� The controller also stops
the fans if a serious malfunction occurs in the ventilation unit�
When the temperature drops or the malfunction has been
remedied, the protection automatically resets itslf in both
cases�
2.2 Optional equipment – automated control
equipment
How to activate and set the functions is described in Section
3, Application. The connection of optional equipment is de-
scribed in the wiring diagram in Section 7, Technical data.
The optional items of equipment can be used
for achieving the type of control required in the following way:
• Boost timer. The boosted operation mode can be switched
in from a control panel or a Premium cooker hood� A sepa-
rate boost timer (push button) can be installed in another
place, e� g� in a sauna, bathroom, scullery, etc�
• Humidity sensor. Detects whether a preset limit value, e�g�
60 % relative humidity (RH), is exceeded and switches the
fan to operate in the boosted flow mode� It can be placed
in a sauna, a bathroom, a scullery, etc� The sensor voltage is
24 V DC�
• Separate fireplace switch. The function can be switched
in from a control panel or a Premium cooker hood� A
separate fireplace switch (push button) can be installed in
another place, e� g� next to an open fireplace� The speed of
the extract air fan decreases and the speed of the supply air
fan increases for a few minutes� This produces excess pres-
sure in the home and in this way "creates" an updraught in
the chimney, which prevents smoke from entering the room
when you light the log-fire�
• Presence detector. The sensor detects movement in the
home and increases the fan speed to the Home value� This
improves the operational economy if the home is nor regu-
larly occupied�
• Carbon dioxide sensor. It is suitable for use in rooms
where the number of occupants varies� Carbon dioxide sen-
sor of standard type: The sensor increases the fan speed to
the Boost value, when a preset maximal value is exceeded,
e�g� 900 ppm�
• Filter guard. The guard measures the pressure differential
across the filter� The pressure differential increases when
the filter becomes fouled� When the preset limit value is
reached, an alarm is initiated to alert the user that the filters
need to be changed� The alarm is activated in response to
the difference in pressure while the fans are running at the
Home speed�
• Negative pressure compensation. Negative pressure
arises in the home when a separate cooker hood or central
vacuum cleaner is used, since the extract airflow becomes
substantially higher than the supply airflow� A separate
sensor (e�g� one that senses the difference in pressure) can
transmit a signal to the controller to increase the supply air
Swegon reserves the right to alter specifications.
R85B.161012