– 29 –
8-10. Cool Airflow Prevention Control
(Heating Operation)
(1) During the heating operation, the indoor fan speed
is controlled automatically in accordance with the
indoor heat exchanger temperature to prevent
blowing the cool air.
Control is performed as shown in Fig. 8-10-1 and
8-10-2.
<RAS-13SKH-E>
According to the
set position
Indoor fan speed
35
32
30
20
Heat exchanger
temperature
(˚C)
U.L. (Ultra Low)
Room temp.
Set temp.
S.L (Super Low)
Room temp.
Set temp.
OFF
>
<
Fig. 8-10-1
< RAS-10SKH-E-1>
According to the
set position
Indoor fan speed
30
25
20
Heat exchanger
temperature
(˚C)
U.L. (Ultra Low)
Room temp.
Set temp.
S.L (Super Low)
Room temp.
Set temp.
OFF
>
<
Fig. 8-10-2
(2) As soon as the defrost operation starts, the in-
door fan stops.
8-11. Defrost Operation
During the heating operation, the outdoor heat
exchanger temperature goes down and sometimes it
is frozen.
In this case, the air conditioner stops the heating
operation and starts the defrost operation to melt ice.
8-11-1. Condition to Start the Defrost
Operation
The defrost operation starts whichever below
conditions are specified.
(1) When the cumulative compressor operation time
is longer than 40 or 90 minutes and difference
between the indoor heat exchanger temperature
and the room temperature is less than the
specified value. (This value is decided by the
microprocessor.) (Control example is shown in Fig.
8-11-1. In case of B or C, the defrost operation
starts.)
(2) When the current limit control or the high
temperature limit control is performed for total of
90 minutes.
Cumulative
compressor
operation time
40 90
Indoor heat exchanger temp.
–Room temp.
A
B
D
C
(˚C)
19
10
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