10
8.2
Maintenance before a long stop
period (e.g., at the end of the season)
• Let the indoor units run in fan only operation for
about half a day in order to dry the interior of the
units.
Refer to “
6.1 Cooling, heating, fan only,
automatic operation and dry operation
”
on page 7.
• Turn off the power. The remote controller display
disappears.
• Clean air filters and casings of indoor units.
Refer to the operation manual supplied with the
indoor units for details on how to proceed and
make sure to install cleaned air filters back in
the same position.
9.
Symptoms that are not air
conditioner troubles
Following symptoms are not air conditioner troubles:
9.1
The system does not operate
• The air conditioner does not start immediately
after the ON/OFF button on the remote controller
is pressed. If the operation lamp lights, the
system is in normal condition. To prevent
overloading of the compressor motor, the air
conditioner starts 5 minutes after it is turned ON
again in case it was turned OFF just before.
The same starting delay occurs after the
operation mode selector button was used.
• The system does not start immediately after the
power supply is turned on. Wait one minute until
the microcomputer is prepared for operation.
9.2
Fan operation is possible, but cooling/
heating do not work
• Immediately after the power is turned on.
The microcomputer is getting ready to operate
and is performing a communication check with
indoor unit. Please wait 12 minutes (max.) till
this process is finished.
9.3
White mist comes out of a unit
1
Indoor unit
• When humidity is high during cooling
operation. If the interior of an indoor unit is
extremely contaminated, the temperature
distribution inside a room becomes uneven.
It is necessary to clean the interior of the
indoor unit. Ask your dealer for details on
cleaning the unit. This operation requires a
qualified service person.
• Immediately after the cooling operation
stops and if the room temperature and
humidity are low. This is because warm
refrigerant gas flows back into the indoor
unit and generates steam.
2
Indoor unit, outdoor unit
• When the system is changed over to
heating operation after defrost operation.
Moisture generated by defrost becomes
steam and is exhausted.
9.4
The remote controller display shows
“U4” or “U5” and stops, but then
restarts after a few minutes
• This is because the remote controller is
intercepting noise from electric appliances other
than the air conditioner. The noise prevents
communication between the units, causing them
to stop.
Operation automatically restarts when the noise
ceases.
9.5
Noise of air conditioners
1
Indoor unit
• A “zeen” sound is heard immediately after
the power supply is turned on.
The electronic expansion valve inside an
indoor unit starts working and makes the
noise. Its volume will reduce in about one
minute.
• A continuous low “shah” sound is heard
when the system is in cooling operation or
at a stop. When the drain pump (optional
accessories) is in operation, this noise is
heard.
• A low “sah”, “choro-choro” sound is heard
while the indoor unit is stopped.
When the other indoor unit is in operation,
this noise is heard. In order to prevent oil
and refrigerant from remaining in the
system, a small amount of refrigerant is kept
flowing.
• A “pishi-pishi” squeaking sound is heard when
the system stops after heating operation.
Expansion and contraction of plastic parts
caused by temperature change make this
noise.
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