VAI 3-MWN-U_EN - 10/13 - Vaillant
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MAINTENANCE
9 Troubleshooting
The table below describes a selection of problems with their
possible causes and solutions, see Table 9.1.
If these solutions do not solve the problem contact your usual
installer or call your nearest Vaillant office.
SYMPTOMS
POSSIBLE CAUSES
POSSIBLE SOLUTION
The system does not restart immediately
When unit is stopped, it won't restart until 3
minutes have elapsed to protect the system
Wait 3 minutes before starting the unit again
When power is disconnected and reconnected
again, the protection circuit will work for three
minutes to protect the air to air heat pump unit
Wait 3 minutes after inserting the plug and
before starting the unit again
The system does not work at all (the ventilation
does not start)
The power lead is not connected correctly
Connect the power lead correctly
Power supply cut
Reconnect the power supply
The fuse has blown
Replace the fuse. Only use the right fuses for
each model. Do not use wire or other material to
replace the fuse. Fires could be caused
Insufficient cooling or heating
Doors and/or windows open
Close the doors and/or windows
Heat source nearby (e.g. lots of people in the
room)
If possible, remove the heat source
The thermostat is set to an excessively high
temperature in cooling mode or excessively low
temperature in heating mode
Set the temperature properly
Obstacle in front of the air inlet or outlet
Remove the obstacle to allow the air to circulate
properly
The ambient temperature has not reached the
designated level
Wait for a few moments
Dirty or blocked air filter
Clean the air filter (the air filter should be
cleaned every 15 days)
Is there any direct sunlight through the window
during the cooling operation?
Use a curtain to protect the Air to Air heat pump
unit
Noise is heard
During unit operation or when stopping the unit
a gurgling noise may be heard. This noise is
more audible the first 2-3 minutes of operation
This is normal in an Air to Air heat pump unit.
The noise is caused by the refrigerant flowing in
the system).
A cracking noise is heard during operation
This is normal in an Air to Air heat pump unit.
The noise is caused by the casing expanding or
shrinking due to the temperature changes
If the noise is loud and comes from the louvers
during the unit operation, the air filters may be
too dirty
Clean the air filters properly
Smells are generated
This is because the system circulates smells
from the indoor surrounding (furniture,
cigarettes)
This situation does not require any action
Mist or steam come are blown out from the unit
During COOL mode or DRY mode operation,
the indoor unit may blow some mist. This is due
to the sudden cooling of the indoor air.
This situation does not require any action
Table 9.1 Troubleshooting.
