Service Call Q & A; Cooling Mode; Dehumidifying Mode; Heating Mode - Hitachi RAS-18FH6 Service Manual

SERVICE CALL Q & A
Model RAS-18FH6 / RAC-18YH6
RAS-25FH6 / RAC-25YH6

COOLING MODE

The compressor has
Q1
stopped suddenly during
cooling operation.

DEHUMIDIFYING MODE

Q2
Fan speed is not switched over
during dehumidifying operation.
Q3
Cool air comes from the unit during
dehumidifying operation.

HEATING MODE

Q4
The circulation stops
occasionally during
Heating mode.
Q5
When the fan speed is set
at HIGH or MED, the flow
is actually Weak.
Q6
Heating operation stops
while the temperature is
preset at "30".
Q7
When "Auto fan" mode is set,
the indoor fan speed changes
from HIGH through MED to
LOW.
A1
Check if the indoor heat
exchanger is frosted.
Wait for 3-4 minutes
until it is defrosted.
A2
Fan speed is normally set to LOW during
dehumidifying operation.
A3
To have an operation with high dehumidifying
effect, the unit operates at low fan speed.
As a result, cool air comes from the unit.
This phenomenon is not a fault.
A4
It occurs during defrost-
ing. Wait for 5-10
minutes until the
condenser is defrosted.
A5
At the beginning of heating,
the fan speed remains
LOW for 30 seconds. If
HIGH is selected, it
switches to LOW and again
to MED after additional 30
seconds.
A6
If temperature is high in
the outdoor, heating
operation may stop to
protect internal devices.
A7
This is not an error.
The anti cool air function
shows this phenomenon.
– 60 –
If the air conditioner operates
in cooling mode when it is
cold, the evaporator may get
frosted.
In the fan "Auto" mode, the unit
detects the heat exchange
temperature. When the
temperature becomes low,
the fan speed changes from
HIGH, through MED to LOW.