nilan Comfort 350L User manual

USER MANUAL
Comfort 350L / Comfort 350L Polar
CTS602 LIGHT BY NILAN
Version 1.00 - 02.05.2022
B24 Comfort 350L GB

2
Table of contents
General information
Safety ............................................................................................................................................................................................................3
Power supply .........................................................................................................................................................................................3
Introduction ..................................................................................................................................................................................................3
Documentation ......................................................................................................................................................................................3
Data plate ...............................................................................................................................................................................................4
Control panel
Control panel functions ..............................................................................................................................................................................5
Main screen items .................................................................................................................................................................................5
Main screen settings options ..............................................................................................................................................................5
Warnings and alarms ............................................................................................................................................................................6
Settings menu overview ......................................................................................................................................................................6
Service and maintenance
Generally ................................................................................................................................................................................................7
Regular maintenance ..................................................................................................................................................................................7
Filters ......................................................................................................................................................................................................7
Illustration of filter change ..................................................................................................................................................................8
Annual maintenance ...................................................................................................................................................................................9
General cleaning ....................................................................................................................................................................................9
Water trap ..............................................................................................................................................................................................9
Heat exchanger .....................................................................................................................................................................................9
Check air intake and discharge ........................................................................................................................................................ 10
Check ventilation ducts .................................................................................................................................................................... 10
User settings
Setting the ventilation unit ..................................................................................................................................................................... 11
Turn off the ventilation unit ............................................................................................................................................................. 11
Alarm .................................................................................................................................................................................................... 11
Show data ............................................................................................................................................................................................ 12
Date/time ............................................................................................................................................................................................ 12
Week programs .................................................................................................................................................................................. 13
Supply air heating .............................................................................................................................................................................. 14
After-heating element ...................................................................................................................................................................... 15
Humidity control ................................................................................................................................................................................ 15
CO2 Control ......................................................................................................................................................................................... 16
Air exchange ....................................................................................................................................................................................... 16
Filter alarm .......................................................................................................................................................................................... 17
Temperature control ......................................................................................................................................................................... 18
Language ............................................................................................................................................................................................. 18
Alarm list
Comfort ...................................................................................................................................................................................................... 19
Alarm list ............................................................................................................................................................................................. 19
Product data
EU/EC Declaration of Conformity ................................................................................................................................................... 21
Ecodesign data Comfort 350L ......................................................................................................................................................... 22
............................................................................................................................................................................................................... 22
Disposal
The environment - part of the solution ................................................................................................................................................ 23
Ventilation unit ................................................................................................................................................................................... 23

3
General information
Safety
Power supply
Introduction
Documentation
The following documents will be supplied with the unit:
• Quick guide
• Wiring diagram
In the Quick guide you will find important information regarding installation and start-up of the unit. If you require further information
regarding, for instance, installation of accessories or additional settings in the software, or if you need an extended user manual, the
following documents can be downloaded from the Nilan website:
• Installation instructions
• Software instructions
• User Manual
• Wiring diagram
The instructions can be downloaded from www.nilan.dk.
If you have questions regarding installation and operation of the unit after having read the instructions, please contact your nearest
Nilan dealer. A list of Nilan dealers is available on www.nilan.dk.
From factory, the unit has been tested and is ready for operation.
CAUTION
Always disconnect the power supply to the unit if an error occurs that cannot be rectified via the control panel.
CAUTION
If an error occurs on electrically conductive parts of the unit, alway contact an authorised electrician to rectify the error.
CAUTION
Always disconnect the power to supply to the unit before opening the unit doors, for instance for installation, inspection,
cleaning and filter change.
ATTENTION
The unit must be started up immediately after installation and connection to the duct system.
When the ventilation unit is not in operation, humidity from the rooms will enter the duct system and create condensate
water that can run out of the valves and cause damage to floors and furniture. Condensation may also form in the ven-
tilation unit, which can damage its electronics and fans.

4
Data plate
Nilan’s data plate is situated on the top left of the unit.
ATTENTION
When contacting Nilan with questions about the product, it is important to have the unit name and serial no. (SN) ready.
From this information, the service department can find all information about the unit in question and thus help with
information and answer questions about what the unit consists of/contains, and what software is used.
The type of the ventilation unit can also be found in the user panel menu under “Show data”.

5
Control panel
Control panel functions
Main screen items
The main screen of the HMI panel shows the information and the settings options that a user mostly requires.
Main screen settings options
The settings options that are necessary in daily life can all be set on the main screen of the panel.
1. Shows the current room temperature in the house,
measured via the extract air
2. Shows the current fan speed level
3. Shows the current air humidity in the extract air
4. Shows the current CO2 level in the extract air
(Does not appear if sensor is not installed)
5. Shows operation ikon (see below)
6. Access to the settings menu, where there are several opti-
ons.
Icon User programe active Icon Ventilation unit has stopped
Icon Week programe active Icon Active alarm or warning
If you press current fan speed level, the set fan speed level will
be displayed.
You can change the fan speed level by using the up-and-down
arrows followed by the confirm icon (bottom right) or the cancel
icon (bottom left).
There may be a difference between set fan speed level and the
actual fan speed level as the control system will override the
set level, for instance, at high/low air humidity or during cooker
hood operation.
If you press current room temperature, the set room
temperature will be displayed.
You can change the room temperature by using the up-and-
down arrows followed by the confirm icon (bottom right) or the
cancel icon (bottom left).

6
Warnings and alarms
Settings menu overview
The settings menu is constructed to make it easy to navigate through.
If the ventilation unit is faulty or an error
occurs, there will be either a warning or
an alarm. The icon will appear in the top
right hand corner in the menu bar.
If you press the symbol, a brief descrip-
tion of the warning or the alarm will be
displayed.
You will find more detailed descriptions in
the "Alarm List" section of this document.
When the problem has been solved, you
can reset the warning or alarm by
pressing “Clear Alarm”.
You navigate through the settings menu by pressing the arrow below or above.
If you want to access a menu, tap the text for that menu and it will open.

7
Service and maintenance
Generally
A ventilation unit from Nilan can last for many years if it is properly serviced and maintained. Ventilation units are often hidden away,
and they are therefore rarely given attention in everyday life. But just as you maintain your car, your ventilation unit will need servic-
ing regularly to keep it functioning properly.
If appropriate service and maintenance are not carried out, the ventilation unit may get damaged. It can also result in increased energy
consumption and a poorer indoor climate. Less air will run through the unit even if the fans are running faster. But the ventilation unit
does not operate well with dirty filters, a clogged up heat exchanger and dusty fans.
You can set an alarm in your calendar on your phone that will notify you when your ventilation unit is due a service. Alternatively, you
can make a service appointment with your local Nilan dealer or service company.
Regular maintenance
Filters
The primary purpose of the filters is to protect the ventilation unit and especially the heat exchanger and the fans that could otherwise
become damaged by dust and dirt.
Dirty filters result in a poorer indoor climate and a higher energy consumption. Dirty filters must therefore be replaced. Dirty filters
can also affect the humidity control system in the ventilation unit so it no longer works as intended.
The factory setting of the control system is set to 90 days, which will suit most installations. But if you live in a city close to a heavily
congested road, you may need to replace the filters more often. Conversely, if you live in a rural setting, you may not need to replace
filters quite as often.
The standard filters in the ventilation unit are ISO Coarse > 65% (G4). If you install a pollen filter ISO ePM1 50-65% (F7), you will not
need to replace the pollen filter as often, as its filter area is larger. It may then only be necessary to replace the pollen filter every sec-
ond or third time, depending on its condition.

8
Illustration of filter change
1.Before opening the door, switch off the unit on the con-
trol panel under OPERATION.
2. Loosen the brackets in the door and tilt the left door to
the side.
3. Remove the two filters from the unit. 4. It is advisable that you vacuum the filter chambers for
potential dirt and dust.
5. Remove the filter sheet from the filter frame. 6. Keeping the smooth side facing downwards, place the
new filter sheet in the filter frame.
7. Press the filter sheet firmly in place and carefully push
it to the sides of the filter frame.
Place the filter in the unit with the filter sheet facing
upwards.
8. Turn on the unit and press the ALARM icon to reset the
warning.

9
Annual maintenance
General cleaning
The ventilation unit should be cleaned on the inside once a year. Dust may escape through the filters and potentially mix with moisture
from the extract air.
You may want to vacuum the ventilation unit before you clean it on the inside using a slightly damp cloth. Be careful around potentially
sharp edges. Be careful not to get water into the electrical control system.
The ventilation unit should also be cleaned on the outside using a slightly damp cloth and a mild detergent.
Valves in the ceiling
Over time a ring may develop around the inlet valves. This is a natural occurrence caused by dust in the air in the room. It is not due to
defective filters or filters not being replaced.
Since painted ceilings are only rarely washable, we recommend that you vacuum the area around the valves before wiping them with
a slightly damp cloth.
It is a good idea to detach the valves and then clean them when necessary. The valves have been set by the installer at a specific air
volume, so it is important that you do not turn them, as this will change the setting and unbalance the ventilation system.
Water trap
During cold periods when the ventilation unit operates with high efficiency heat recovery, the extract air creates condensation. It is
important that this water can drain freely from the condensate tray. If it cannot drain properly, it will eventually leak out of the unit
door and, potentially, cause water damage.
Water trap with ball
1. Pour water into the condensate tray and check that it drains away
2. If the water drains away, everything is in order
3. If the water does not drain away, you should check the water trap and the drain to locate any blockages
Water trap without ball
1. Pour water into the condensate tray
2. Close the door of the ventilation unit
3. Start the ventilation unit and let it run for 10 minutes
4. Open the door of the ventilation unit and check that the water has drained away and that it has not run back into the condensate
tray
5. If the water has drained away, everything is in order
6. If the water has not drained away, you should check the water trap and the drain to locate any blockages
Heat exchanger
The counterflow heat exchanger is a central part of the ventilation unit. It heats up the cold outdoor air with energy from the warm ex-
tract air. To maintain a high level of heat recovery, it is important that the heat exchanger is not clogged with dirt.
Experience indicates that it should not be necessary to lift out and clean the heat exchanger every year. However, if it appears to be
dirty, you should lift it out and clean it.
The easiest way to clean the counterflow heat exchanger is in the shower. Use lukewarm water and rinse it well from both sides. Allow
it to drip off before remounting it in the ventilation unit.
WARNING
Stop the ventilation unit on the control panel and switch off the power supply for the ventilation unit before you open
the front door to the unit.
ATTENTION
If you have not installed a water trap with ball, you must check the condensate drain every autumn before the weather
turns cold. (Condensation typically forms when the outdoor temperature < 10°C)

10
Check air intake and discharge
It is important for operation of the unit that air can freely move through the air intake and discharge.
If roof stacks have been fitted to the air intake and discharge, check that they are not blocked with birds' nests, leaves or other dirt
which can hamper air passage.
If, instead of roof stacks, grilles have been mounted in facades or eaves, check that they are not clogged with leaves or dirt. Grilles are
particularly likely to become clogged.
Check ventilation ducts
It is important for operation of the unit that there is free air passage through the ventilation ducts.
After some years of operation, dirt will attach itself to ventilation ducts or tubes, and accumulations may lead to higher pressure drop
in the ducts, leading to higher power consumption. It is therefore important to clean out the ducts when too much dirt has collected.
After attending to the inlet and outlet valves, it will be advisable to have them adjusted again, to ensure optimum operation of the ven-
tilation system.
However, it will not be necessary to clean ducts more than every few years.

11
User settings
Setting the ventilation unit
Turn off the ventilation unit
If you need to open the doors to the ventilation unit in connection with servicing or filter replacement, remember to turn off the venti-
lation unit. You do this under the menu item “Operation”.
> Unit on/off
Alarm
You can read off warnings and alarms under the “Alarm” menu item. This is also where you reset them once the problem has been
solved.
> Alarm
When the ventilation unit is off, this icon is displayed on the main screen of the control panel in the top righthand corner.
ATTENTION
Before touching the electrical installations, you must ensure that the power supply is disconnected.
ATTENTION
It is important that the ventilation unit is not turned off for lengthy periods of time, as this may cause problems with
condensate water in the duct system.
> Unit on/off Settings:
Description:
Off / On
The ventilation unit must be turned off before the doors are
opened during service.
If an alarm or a warning is active, the alarm icon will be displayed in the upper righthand corner of the control panel.
> Alarm number and name Description: When you press the alarm, the following information will be dis-
played:
• Alarm ID number
• Type of alarm
• Critical alarm or warning
(The alarm list will inform you of how to proceed.)
ATTENTION
Until the problem has been solved, the alarm or warning will remain active. When the problem has been solved, you will
be able to reset the alarm or warning by pressing "Clear alarm".

12
Show data
You can access current operational data for the ventilation unit. This will allow you to check that the unit operates satisfactorily and
to identify the cause of potential alarms.
>Show data
Date/time
It is important to set date and time correctly. It makes it easier to trace potential faults when an error is being reported. When logging
data, it is important to be able to follow the history. You set the time in the settings menu.
> Date/time
> Operating state Description: Shows the operating setting in which the unit is running.
> Bypass Description: Shows whether the bypass damper is open or closed.
> T2 Supply air Description: Show the supply air tempereture, if an after-heating element is
not installed.
> T3 Extract air / Room Description: Shows the room temperature as an average of the entire house.
> T4 Discharge Description: Shows the discharge air temperature.
> T7 Supply air Description: Shows the supply air temperature provided an after-heating
element has been installed.
> T8 Outdoor air Description: Shows the outdoor temperature before reaching the pre-heat-
ing element, if installed.
> T9 Water after heat Description: Shows the temperature in the water after-heating element.
> Air humidity Description: Shows the current air humidity in the house.
> CO2 level Description: Shows the current CO2 level in the house (only if installed).
> Supply air fan Description: Shows the level at which the supply air fan is operating.
> Extract air fan Description: Shows the level at which the extract air fan is operating.
> Unit information Description: Select "Unit information" for more information.
> Unit type Description: Shows the name of the unit.
> Software version Description: Shows the installed software version.
> Panel software Description: Shows installed software version on the panel.
> Year Description: Press “Year” on the panel and select the current year.
> Month Description: Press “Month” on the panel and select the current month.
> Day Description: Press “Day” on the panel and select the current day of the week.
> Hour Description: Press “Hour” on the panel and select the current hour of the day.
> Minute Description: Press “Minute” on the panel and select the current minute.

13
Week programs
You can program the ventilation unit to run in accordance with specific settings at fixed times during the day and week via a week pro-
gram.
> Week program
On the main screen of the control panel, in the top right corner, the Week program icon will be displayed when active.
> Select program Settings:
Standard setting:
Description:
De-activated / Program 1 / Program2 / Program 3
De-activated
The control allows you to set 3 programs for different situa-
tions e.g.:
• Normal operation
• Holliday operation
> Edit program Description: The selected Week program is now active and can be edited.
> Monday Settings: Here weekday is selected.
>Function 1 Settings: Here you select the function you want to edit.
> Start time Settings:
Standard setting:
Description:
Hours and minutes
6:00
Set the time for the program to start. The program will run with
the set values until the next change in the Week program.
> Ventilation level Settings:
Standard setting:
Description:
De-activated / Level 1 / Level 2 / Level 3 / Level 4
Level 3
Select the desired fan speed level here.
> Room temperature Settings:
Standard setting:
Description:
5  40 °C
22 °C
Set the desired room temperature here.
> Copy for next day Description: Once the values for the Monday program have been set, it is
possible to copy these to the next day.
The same settings are made for
all functions.
> Reset program Settings: You can reset the program by selecting the “Approve” icon.

14
Supply air heating
You will only have this menu item if an after-heating element has been installed and it has been activated in “Service settings”.
When the room temperature (measured in the extract air) falls below the desired room temperature that has been set in the display,
the heat pump and the after-heating element start heating the supply air.
> Supply air heating
Heating curve
ATTENTION
An after-heating element is not included as standard. However, you can order it as an additional extra, and it can also be
retrofitted.
> Outdoor temp. compensation Settings:
Standard setting:
Description:
Off / 1 10
Off
Off: The heating of the supply air is off.
1 10: Choose the curve in accordance with which the control
system should regulate.
> 1 Description: You have selected curve controlled heating of the supply air.
The supply air temperature is then controlled by the outdoor
temperature and not by the current room temperature.
> Offset curve Settings:
Standard setting:
Description:
-15  10 ºC
0 ºC
You can shift the curve to better meet the heating require-
ments of the dwelling.
> Min. supply air tempera-
ture
Settings:
Standard setting:
Description:
5  40 ºC
20 ºC
Minimum supply air temperature
> Max. supply air tempera-
ture
Settings:
Standard setting:
Description:
20  85 ºC
40 ºC
Maximum supply air temperature
> Room temperature Description: Shows the current room temperature.
The same settings apply to all curve levels
Max. temperature
Min. temperature
Supply air temperature
Outdoor temperature
20
-20-15-10-505101520
30
40
50
60
70
80
90
100
1
2
3
4
6
7
8
9
10
5

15
After-heating element
You will only have this menu item if an electrical after-heating element or a water after-heating element has been installed, and if it
has been activated in “Service settings”.
If you want to be able to control the supply air temperature, you will need to install an after-heating element. This allows you to control
the supply air temperature irrespective of the outdoor temperature. The after-heating element can also contribute towards the heat-
ing of the dwelling.
> After-heating element
Humidity control
The primary purpose of ventilation is to extract humidity from the house so it does not damage the building, and to achieve a good in-
door climate. During long periods with sub-zero temperatures, air humidity in the house may fall to a level that is critical for the build-
ing and for the indoor climate. Wooden floors, furniture and walls can be damaged by very dry air, which also whirls up dust, resulting
in a poor indoor climate.
This is rectified by an integrated humidity control system that maintains good, relative air humidity. When the average air humidity in
the house falls below a set level (default set at 30%), ventilation may be reduced. It will typically only be for a short period of time. This
will help avoid further reduction of the air humidity in the house.
The humidity control system also has a function that allows increased ventilation, should the air humidity increase, for instance when
having a bath. The risk of mould growth in the bathroom is reduced, and the bathroom mirror will rarely steam up.
The humidity control system follows the average air humidity level measured over the previous 24 hours. In this way the system au-
tomatically adapts to summer and winter conditions.
> Humidity control
ATTENTION
An after-heating element is not included as standard. However, you can order it as an additional extra, and it can also be
retrofitted.
> Turn on/turn off Settings:
Standard setting:
Description:
Off / On
Off
The user can turn the after-heating element on and off here.
> Vent.low humidity Settings:
Standard setting:
Description:
De-activated / Level 1 / Level 2 / Level 3
Level 1
When the current humidity drops below the low humidity level,
the ventilation unit switches to the set ventilation level.
> Low humidity level Settings:
Standard setting:
Description:
15  45%
30%
When current humidity below this value falls, the ventilation
level set above is activated.
> Vent.high humidity Settings:
Standard setting:
Description:
De-activated / Level 2 / Level 3 / Level 4
Level 3
At high humidity levels, for instance when having a bath, the
unit changes to the set fan speed level.
> Max time hi.humidity Settings:
Standard setting:
Description:
De-activated / 1 - 180 min.
60 min.
The function “High humidity” stops when actual humidity falls
below 3% above the average air humidity.
However, this time limit will stop operation if it fails within the
set time period.

16
CO2 Control
This menu is only displayed if a CO2-sensor has been installed, and the function has been chosen under Service settings.
If the number of people using a building varies considerably, controlling ventilation through the CO2 level in the extract air may be a
good solution. This function is often used in offices and schools where use varies greatly during the day and during the week.
> CO2 control
Air exchange
Low humidity in the dwelling can be prevented by reducing ventilation at low outdoor temperatures. This function is useful for instance
in countries with regular sub-zero temperatures and at high altitudes where the outdoor air is very dry.
> Air exchange
ATTENTION
A CO2 sensor is not a standard part of all ventilation units, but may be purchased as an accessory.
> Vent.high CO2 Settings:
Standard setting:
Description:
De-activated / Level 2 / Level 3 / Level 4 /
Level 3
Here you set the fan speed level at which the unit is to operate
at high CO2 level.
> High CO2 level Settings:
Standard setting:
Description:
650  2500 ppm
800 ppm
Here you set the CO2 level at which the unit is to switch to high
fan speed level.
> Normal CO2 level Settings:
Standard setting:
Description:
400  700 ppm
600 ppm
Here you set the CO2 level at which the unit is to switch to nor-
mal fan speed level.
> Level winter low Settings:
Standard setting:
Description:
Level 1 / Level 2 / Level 3 / Off
Off
Here you specify at what fan speed level you want the unit to
operate at low outdoor temperatures.
Off means that this function is de-activated.
> Temperature winter low Settings:
Standard setting:
Description:
-20  40 °C
0 °C
Here you specify at which outdoor temperature the “Winter low”
function is to be activated.

17
Filter alarm
From factory, the filter alarm has been set to signal filter replacement every 90 days. You can set the timer to fit the level of pollution
in the area where the ventilation unit has been installed.
If someone in the household has pollen allergies, it is recommended that you install a pollen filter in the outdoor air intake.
> Filter alarm
ATTENTION
It is important to change the filters regularly and when needed. Dirty filters reduce the efficiency of the ventilation unit
and result in a poorer indoor climate and higher power consumption.
> Days to change Settings:
Standard setting:
Description:
De-activated /30 / 60 / 90 / 180 / 360
90 days
The number of days between filter changes can be set as
required.

18
Temperature control
If you have not installed an after-heating element, use the settings to control the bypass damper.
It is necessary to install an after-heating element if you want to control the supply air temperature and for it to contribute towards the
heating of the dwelling. An after-heating element allows you to control the supply air temperature, regardless of the outdoor temper-
ature.
You can install an external electrical or water after-heating element in the supply air duct.
> Temp. regulation
Language
The default language for the ventilation unit is Danish. You can change the texts to other languages in the settings menu.
> Language (DK - Sprog)
ATTENTION
During periods when heating is not required in the dwelling, the supply air temperature may fall below the minimum
temperature.
> Min. supply summer Settings:
Standard setting:
Description:
5  16 °C
14 °C
Here you set the supply air temperature that you want the ven-
tilation unit to be able to provide, as a minimum, during sum-
mer, when the unit is in heating mode.
> Min. supply winter Settings:
Standard setting:
Description:
14  35°C
16 °C
Here you set the supply air temperature that you want the ven-
tilation unit to be able to provide, as a minimum, during winter,
when the unit is in heating mode.
NB: Only possible if an after-heating element has been
installed.
> Max. supply summer Settings:
Standard setting:
Description:
5  50°C
35 °C
Here you set the supply air temperature that you want the ven-
tilation unit to be able to provide, as a maximum, when heating
is required.
NB: This option is only shown if an after-heating element has
been installed and activated.
> Max. supply winter Settings:
Standard setting:
Description:
5  50 °C
35°C
Here you set the supply air temperature that you want the unit
to be able to provide, as a maximum, during winter.
NB: This option is only shown if an after-heating element has
been installed and activated.
> Summer/vinter shift Settings:
Standard setting:
Description:
5  30 °C
12 °C
Here you set the temperature for the shift between summer
and winter operation.
• If the outdoor temperature is higher, the unit will operate in
summer mode
• If the outdoor temperature is lower, the unit will operate in
winter mode
> Dansk Description: Select the language you want on the panel.

19
Alarm list
Comfort
Alarm list
The following list applies to Comfort ventilation units with the CTS602Light control. The events are divided into the following
categories:
Warning Operation continues, but an incident has occurred that should be kept in mind.
Alarm Operation is partially or completely stopped as it is a critical fault that needs immediate attention.
ID Type Display text Description / cause Troubleshooting
1 Hardware error Error in the hardware of the control system. Note alarm and reset it.
If the alarm does not disappear contact
service.
2 Alarm timeout A warning alarm has become a critical alarm. Note alarm and reset it.
If the alarm does not disappear contact
service.
3 Fire alarm
activated
The ventilation unit is stopped due to the fire
thermostat being activated.
If there is no fire, check the connection to the
fire thermostat.
If okay, contact service.
7 Frost in
after-heating
element
Units with a T9 sensor: Water heating element
could not reach 20°C within 6 min.
Units without a T9 sensor: Frost thermostat in
water heating element triggered.
Check for adequate insulation around the
water heating element and its connections.
Reset alarm.
8 Frost thermo-
stat triggered
Only on units with a T9 sensor: Frost thermo-
stat in water heating element triggered.
Check for adequate insulation around the
water heating element and its connections.
Reset alarm.
10 Overheating of
electrical
after-heating
The electrical heating element has over-
heated. Lack of airflow due to, for instance,
blocked filters, blocked air intake or defect
supply air fan.
Make sure that air is blown into the house.
Make sure the filters are clean.
Check that the outdoor air intakes is not
blocked.
Reset alarm.
Contact service if the above does not solve the
problem.
11 Low flow over
the electrical
heating ele-
ment
Lack of airflow in supply air. See alarm code 10.
15 The room
temperature is
too low
When the room temperature is below 10°C, the
unit will stop in order to prevent further cool-
ing of the house. This may, for instance, be
during a period when the house is unoccupied
and the heating system is off.
Heat up the house and reset the alarm.

20
16 Software error Fault in the ventilation unit software Contact service.
17 Watchdog
warning
Fault in the ventilation unit software Contact service.
18 Content of
database
changed
Parts of the program setting have been lost.
This may be due to a prolonged power cut or a
lightning strike.
The unit will continue to operate with standard
settings.
Reset alarm.
Contact service if the unit does not operate to
your satisfaction/ as before, as some subpro-
grams may have been lost. (Subprogram is
only available for service).
19 Change filter The filter monitor has been set at X amount of
days for check-up/change of filter.
Clean/change filter.
Reset alarm.
21 Check date and
time
Is displayed during power cuts. Set the date and time.
Reset alarm.
22 Error supply air
temperature
The desired heating of the supply air is not
possible.
(applies only with after heating element)
Set a lower supply air temperature.
Reset alarm.
71 Error de-icing
heat exchanger
Max. de-icing time exceeded for counterflow
heat exchanger.
This may be due to the unit being exposed to
very low temperatures.
If resetting the alarm does not help, contact
service. Register the current operating tem-
peratures from the “SHOW DATA” menu in
order to ease the service process.
91 Missing
expansion PCB
Expansion PCB is missing. Contact service.
92 Backup error Error writing or reading installer settings Contact service.
96 Error in damper
test
Damper (open / closed) not fulfilled. Reset alarm.
If it does not help contact service.