Hitachi RAS-18CH7 Service Manual page 53

Heating operation
Air does not come out when
Q6
starting a heating operation.
Air does not come out
Q7
sometimes while in a heating
operation.
The fan speed is set to "HI"
Q8
or "MED" but the heating
operation starts with a LO fan
speed.
The operation stops during
Q9
a heating operation while the
room temperature is set at
"30".
The outdoor fan does not
Q10
move at a heating operation
by the service switch.
Auto fresh defrosting
Heating has been turned off by the main
Q11
operation but the "Hot keep lamp" lights and
the outdoor unit operations.
It is not a trouble. The fan is
A6
stopped to avoid cold wind.
Defrosting is on. Wait for 5–
A7
10 minutes unit the outdoor
unit is defrosted.
The heating operation
A8
starts with a LO fan speed
for 30 seconds. If the fan
speed is set to HI, the
operation starts with LO fan
speed, followed by MED
fan speed for 30 seconds
and then by HI fan speed.
If a heating operation is per-
A9
formed when the exterior
temperature is high, the op-
eration may stop to protect
the equipment.
It is not a trouble.
A10
When heating, the outdoor
fan is stopped to avoid ex-
cessive pressure rise.
"Auto fresh defrosting" operates. When
A11
stopping the operation, whether the outdoor
unit is frosted or not is checked and, if in the
affirmative, defrosting is performed before
stopping the operation.
– 57 –
When starting the operation,
the heat exchanger is cold
and, therefore, the fan is
stopped.
Wait 2–3 minutes.