White Mist Comes Out Of A Unit; The User Interface Display Reads "U4" Or "U5" And Stops, But Then Restarts After A Few Minutes; Noise Of Air Conditioners; Dust Comes Out Of The Unit - Daikin VRV Series Operation Manual

9.5 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.
9.6 The user interface display reads "U4"
or "U5" and stops, but then restarts
after a few minutes
• This is because the user interface 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.

9.7 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.
2 Indoor unit, outdoor unit
• A continuous low hissing sound is heard
when the system is in cooling or defrost
operation.
This is the sound of refrigerant gas flowing
through both indoor and outdoor units.
• A hissing sound which is heard at the start
or immediately after stopping operation or
defrost operation.
This is the noise of refrigerant caused by
flow stop or flow change.
3 Outdoor unit
• When the tone of operating noise changes.
This noise is caused by the change of
frequency.

9.8 Dust comes out of the unit

• When the unit is used for the first time in a long time.
This is because dust has gotten into the unit.

9.9 The units can give off odours

• The unit can absorb the smell of rooms,
furniture, cigarettes, etc., and then emit it again.

9.10 The outdoor unit fan does not spin

• The speed of the fan is controlled in order to
optimise product operation.

9.11 The display shows "

• This is the case immediately after the main
power supply switch is turned on and means
that the user interface is in normal condition.
This continues for one minute.
9.12 The compressor in the outdoor unit
does not stop after a short heating
operation
• This is to prevent oil and refrigerant from
remaining in the compressor. The unit will stop
after 5 to 10 minutes.
9.13 The inside of an outdoor unit is warm
even when the unit has stopped
• This is because the crankcase heater is
warming the compressor so that the compressor
can start smoothly.

9.14 Does not cool very well

• Program dry operation.
Program dry operation is designed to lower the
room temperature as little as possible refer to
"6.2 Program dry operation".
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