VALLOX 252 D
11
TROUBLESHOOTING
After a power failure, the unit will start at the basic speed. All the other adjustments and setpoints chosen will remain in the memory of the unit.
SYMPTOM
CAUSE
DO THIS
"Bus fault" message is displayed
and unit runs at fan speed 1.
• There is a wiring fault in the CO
2
sensor,
huminity sensor or in the control panel.
9
• Contact a service representative. The couplings have to be checked
and repaired if needed.
"Freezing alert" message is
displayed and the unit is
stopped.
• The defrosting of the water circulated
radiator is operating.
NOTE! If there is no anti-freezing agent in the water of
the radiator, there is a risk that the radiator will freeze.
10
• Immediately sort out the situation. Contact your service representative
to find out if there is any anti-freezing agent in the radiator. Check if
the circulating water pump has been broken, if the heating boiler is
out of operation, etc. The situation may pass by itself when supply
air temperature rises above 10˚C, but do not await that.
The desired automatic adjustment
does not stay activated.
• There is a fault in the humidity sensor,
pressure sensor or CO
2
sensor; one of
the sensors is broken or missing.
11
• Contact a service representative. The mounting and couplings of the
sensors have to be checked. (The sensors are optional.)
The unit does not obey the control
panel.
13
• Remove the plug from the wall outlet, wait for 30 seconds and put it
back. If this does not help, contact a service representative.
"Carbon dioxide alarm!!" message
is displayed and the unit is
stopped.
• CO
2
alarm. Carbon dioxide content has
exceeded 5000 ppm for more than two
minutes. This may be because of a fire, for
instance.
14
• If there is a fire, take the necessary steps.
• The unit can be brought back to operation by removing the plug from
the wall outlet, waiting for 30 seconds and putting the plug back.
The filter guard symbol ( ) is
displayed and the unit operates
otherwise normally.
• Pressure in the filter guard (pressure
difference switch) has risen above
the setup, or speed is 7 or 8.
15
• Check the cleanliness of the filters and the unit. Clean or replace the
filters, if necessary. Also check the external grille.
• The door switch may be broken or has not
closed properly.
• The socket is dead; the fuse may have
burned out, for instance.
• The glass tube fuse protecting the internal
electronics of the unit (located on the control
board behind the protective plate) may have
burned out.
The unit is deaf, the fans do not
rotate, and none of the indicator
lamps of the control panel is lit.
12
• Check the door switch and the fuses. The unit has a glass tube fuse,
T800mA.
• If needed, contact a service representative (in order to check the
glass tube fuse, for instance).
Outdoor air is cool when entering
the house.
• Air cools down in the attic ducts.
• The heat recovery cell has frozen,
and extract air cannot heat outdoor
air.
• The post-heating radiator is not
functioning.
• The extract air filter or the cell is
clogged.
• The initial adjustments for ventilation
have not been made.
1
• Check the insulation of the attic ducts.
• If the heat recovery cell has frozen, check the defrosting protection
setpoint. You may increase the setpoint by 1 or 2˚C, or you can bend
the sensor closer to the cell, which causes the supply air fan to stop
earlier (see the instructions for using the control panel, Section
1.3.20). Defrost the cell before closing the door.
• If the post-heating radiator does not operate, check to see if
overheating protection prevents it from operating. Press the
overheating protection button, and measure the temperature of supply
air inside the unit when the door is closed. If, even after this, the
radiator does not function, contact a service representative.
• Check the cleanliness of the filters and the heat recovery cell.
The supply air fan keeps stopping.
• Stopping of the supply air fan is
active.
NOTE! If you decrease the threshold by too much,
the cell may freeze. See item 1 on this page.
2
• The fan stops less often and the efficiency of the heat recovery cell is
enhanced if the setpoint is decreased by 1 or 2˚C.
(See the instructions for using the control panel, Section 1.3.20.).
The supply air fan stops and starts
too frequently.
• The difference between the stopping
and starting temperatures is too small.
3
• Increase the difference by 1 or 2˚C, thereby lengthening the interval
between the stopping and starting of the supply air fan. (See the
instructions for using the control panel, Section 1.3.19).
The maintenance reminder symbol ( )
is displayed and the unit operates
otherwise normally.
• The maintenance reminder lights up the
maintenance reminder symbol in the
main display of the control panel at an
interval of approximately 4 months
(factory setting).
• You may change the interval (see the
instructions for using the control panel,
Section 1.3.18.).
4
• Check the cleanliness of the filters and the unit, and clean or replace
the filters if needed. Check the external grille as well.
• Acknowledge the maintenance reminder symbol to make it
disappear. (See the instructions for using the control panel, Section
1.3.7.).
"Exh. air sensor fault" message is
displayed and the unit is stopped.
• There is a fault in the defrosting
sensor.
5
• Contact a service representative. The sensor mounting has to be
checked, and the sensor has to be replaced if necessary.
"Sup. air sensor fault" message is
displayed and the unit is stopped.
• There is a fault in the supply air
sensor.
6
• Contact a service representative. The sensor mounting has to be
checked, and the sensor has to be replaced if necessary.
"Ind. air sensor fault" message is
displayed and the unit is stopped.
• There is a fault in the extract air
sensor.
7
• Contact a service representative. The sensor mounting has to be
checked, and the sensor has to be replaced if necessary.
"Out air sensor fault" message is
displayed and the unit is stopped.
• There is a fault in the outdoor air
sensor.
8
• Contact a service representative. The sensor mounting has to be
checked, and the sensor has to be replaced if necessary.
