DC Inverter U-Match Series Cassette Type Unit
49
(2) The following situations are not operation failures.
Problem Time of occurrence Cause
Mist comes
from the air
During operation.
If the unit is running under high
humidity, the wet air in the room
will be quickly cooled down.
Mist comes
from the air
conditioner.
System switches to heating
mode after defrosting.
Defrosting process will generate
some water, which will turn to
The air conditioner is buzzing
at the beginning of operation.
Temperature control will be
buzzing when it starts working.
The noise will become weak
Dust comes
from the air
conditioner.
When the unit is turned on, it
purrs.
When the system is just started,
the refrigerant is not stable.
About 30s later, the purr of the
About 20s after the unit first
enables the heating mode or
there is refrigerant brushing
sound when defrosting under
It’s the sound of 4-way valve
switching direction. The sound
will disappear after the valve
changes its direction.
There is hissing sound when
the unit is started or stopped
and a slight hissing sound
during and after operation.
It’s the sound of gaseous
refrigerant that stops flowing and
the sound of drainage system.
There is a sound of crunching
during and after operation.
Because of temperature change,
front panel and other
components may be swelled up
and cause abrasion sound.
There is a hissing sound
when the unit is turned on or
suddenly stopped during
operation or after defrosting.
Because refrigerant suddenly
stops flowing or changes the
flow direction.
The unit starts operation after
being unused for a long time.
Dust inside the indoor unit
comes out together with the air.
The air
conditioner
generates
During operation.
The room smell or the smell of
cigarette comes out through the
indoor unit.