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8-2-3. Heating Operation
Transferring of heating operation signal from indoor
unit to outdoor unit starts.
The indoor fan motor operates by the room tempera-
ture when selecting “AUTO” of “FAN” as shown in
Fig. 8-2-6, and operates with a set air flow when
selecting “Low” to “High”.
However, to prevent cold draft, revolution speed of
the fan is restricted by indoor heat exchanger when
air flow is AUTO (Fig. 8-2-7) and starting of FAN
Manual.
[Basic control]
*1, *2 : Approximate revolution speed of M+ and L to
linear according to temperature.
Fig. 8-2-6 Setting of air flow
[Cold draft preventing control]
The upper limit of fan revolution speed is shown
below.
Fig. 8-2-7 Cold draft preventing control
NOTES :
(1) Stops for 2 minutes after thermostat-OFF.
(2) 24°C when the set temp. is 24°C or more
Set temp. when the set temp. is below 24°C
(3) SUL : Super ultra low
[In starting and in stability]
FAN
AUTO
FAN
Manual
In starting
• Until 12 minutes
passed after
operation start
• When 12 to 25
minutes passed
after operation start
and room temp. is
3°C or lower than
set temp.
• Room temp. < Set
temp. –4°C
In stability
• When 12 to 25
minutes passed
after operation start
and room temp. is
higher than (set
temp. –3°C)
• When 25 minutes or
more passed after
operation start
• Room temp. ≥ Set
temp. –3,5°C
The outdoor unit controls the outdoor fan based
upon the operation signal sent from the indoor unit,
and also controls revolution speed of the compres-
sor motor.
The power coupler (IC20) for four-way valve is
turned on, and turned off in defrost operation.
(1) Heating capacity control
Calculate the difference between temperature
detected by room temp. sensor every minute and
the set temp. set on “Temp. indicator” and
variation amount of room temp.
Then, obtain the correction amount of the
command signal, and correct the current fre-
quency command signal.
(2) High-temp. release control
If temperature of the indoor heat exchanger
detected by the indoor heat exchanger sensor is
55°C or higher, compressor motor speed is
gradually lowered to prevent over-temp. rising of
compressed pressure.
If temperature becomes below 48°C, return to
above item (1).
(3) Current release control
The input current of compressor and outdoor fan
motor (Precisely inverter main circuit control
section) which occupy most of air conditioner
input is detected by the outdoor current sensor.
The compressor motor speed is lowered gradu-
ally according to the range of TO (outside air
temp.) if the input current exceeds the current
value determined in each zone as shown in Fig.
8-2-8 so that the input current does not exceed
the set value.
In case that the current lowered by approx. 0,5A
than each set value, return to above item (1).
0
–0,5
–1
–1,5
–2
–5,0
–5,5
(Room temp.) –
(Set temp.)
Set
temp.
[FAN AUTO]
*
2
*
1
LOW
M+
HIGH
33
*
3
*
2
32
44
43
20
19
31
30
A
A – 8
A + 4
A – 8
HIGH
SUL
SUL
FAN
AUTO
Starting
of FAN
Manual
Approximate
revolution speed
of HIGH and SUL
linear by Tc.
Stop
( NOTE :
*
1)