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What the units include can vary depending on the sales area.
Vallox
121
SE
Symptom
Cause
Do this
1
Outdoor air coming to the
dwelling is cold.
• Air cools down in the attic ducts.
• The heat recovery cell is frozen, which is why extract air
cannot heat outdoor air.
• The post-heating radiator does not work.
• The extract air filter or cell is clogged.
• The initial adjustment of ventilation has not been done.
• Check the insulation of the attic ducts.
• Check the cleanliness of the filters and heat recovery cell.
2
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 circa 4 months (factory setting).
• You may change the interval (see the operating instructions
for control panel, Section 3.2).
• Check the cleanliness of the filters and the unit. If needed, clean or
replace the filters. Also check the external grille.
• Reset the maintenance reminder symbol (see the operating
instructions for control panel, Section 3.1.).
3
“Exh air sensor faulty”
message is displayed and
the unit is stopped.
• There is a fault in the freezing protection sensor.
• Contact a maintenance company. Sensor mounting needs to be
checked and the sensor has to be replaced if necessary.
4
“Sup. air sensor faulty”
message is displayed and
the unit is stopped.
• There is a fault in the supply air sensor.
• Contact a maintenance company. Sensor mounting needs to be
checked and the sensor has to be replaced if necessary.
5
“Ind. air sensor faulty”
message is displayed and
the unit is stopped.
• There is a fault in the extract air sensor.
• Contact a maintenance company. Sensor mounting needs to be
checked and the sensor has to be replaced if necessary.
6
“Out. air sensor faulty”
message is displayed and
the unit is stopped.
• There is a fault in the outdoor air sensor.
• Contact a maintenance company. Sensor mounting needs to be
checked and the sensor has to be replaced if necessary.
7
“Cell sensor faulty”
message is displayed and
the unit is stopped.
• There is a fault in the sensor of the heat recovery cell.
• Contact a maintenance company. Sensor mounting needs to be
checked and corrected if necessary.
8
"Bus fault" message is
displayed and the unit
operates at speed 1 (check
the fan speed).
• Wiring fault in the carbon dioxide sensor, in the control
panel or in the humidity sensor, or the cable is of the wrong
type.
• Contact a maintenance company. The connections have to be
checked and corrected if necessary.
9
“Freezing alert” message
is displayed and the unit is
stopped.
• Antifreeze of the water-circulating radiator is active.
NOTE! If there is no non-freezing solution in the water of
the radiator, the radiator is at risk of freezing.
(Does not apply to the Vallox 121 SE unit)
• Immediately troubleshoot the situation. Consult a maintenance
company to find out if there is any non-freezing solution in the
radiator. Check if the circulation pump is broken, the boiler out of
operation etc. The situation may pass by itself as soon as supply air
temperature exceeds 10 degrees, but do not wait till it happens.
10
The desired automatic
adjustment does not stay
on.
• There is a fault in the humidity or carbon dioxide sensor.
One of the sensors is broken or missing.
• Contact a maintenance company. Sensor mounting and connections
have to be checked. (Sensors are options.)
11
The fans are not running
and no indicator light is lit
at the control panel.
• Door switch may be broken or the door is not quite closed.
• The unit is out of power, for instance because a fuse has
blown.
• The glass tube fuse (located in the control card behind a
protecting plate) protecting the electronics inside the unit
may have blown.
• Check the door switch and fuses. The unit has a T800 mA glass-tube
fuse.
• If needed, contact a maintenance company (for instance to check
the glass tube fuse).
12
The unit does not obey the
control panel.
• Disconnect the plug of the unit from the wall socket, wait for 30
seconds and put the plug back. If this does not help, contact a
maintenance company.
13
“Carbon dioxide alarm”
message is displayed and
the unit is stopped.
• Carbon dioxide alarm. Carbon dioxide content has
exceeded 5000 PPM for two minutes. May be caused by
for instance a fire.
• If there is a fire, take the necessary steps.
• You can make the unit operational by disconnecting the plug from
the wall socket, waiting for 30 seconds and putting the plug back.
14
Filter guard symbol
( ) is displayed and the
unit operates
otherwise normally.
• The pressure in the filter guard (pressure difference switch)
has risen above the adjustment value or speed is 7 or 8
(option).
• Check the cleanliness of the filters and the unit. If needed, clean or
replace the filters. Also check the external grille.
Troubleshooting
MAINTENANCE INSTRUCTIONS
