FILE NO. SVM-02007
– 28 –
[In starting and in stability]
The outdoor unit controls the outdoor fan based upon
the operation signal sent from the indoor unit, and also
controls revolution speed of the compressor motor.
The power coupler (IC20) for 4 way valves is turned
on, and turned off in defrost operation.
(1) Heating capacity control
Calculate the difference between temperature
detected by room temperature sensor every
minute and the set temperature set on “Tempera-
ture indicator” and variation amount of room
temperature.
Then, obtain the correction amount of the com-
mand signal, and correct the current frequency
command signal.
(2) High-temperature 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 temperature
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 occupies most of air conditioner
input is detected by the outdoor current sensor.
The compressor motor speed is lowered gradually
according to the range of TO (outside air tempera-
ture) 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).
In starting
In stability
FAN
AUTO
FAN
Manual
•
Until 12 minutes
passed after
operation start
•
When 12 to 25
minutes passed
after operation
start and room
temperature is 3°C
or lower than set
temperature.
•
Room temperature
< Set temperature
–4°C
•
When 12 to 25
minutes passed
after operation
start and room
temperature is
higher than (set
temp. –3°C)
•
When 25 minutes
or more passed
after operation
start
•
Room tempera-
ture Set tem-
perature –3.5°C
Fig. 8-2-8
(4) Defrost control
1) Detection of frost
In heating operation, time duration while the
compressor operates is counted, and defrost
operation starts by any condition described
below.
a. The counted time is 28 minutes or more, and
status that temperature of the outdoor heat
exchanger detected by the outdoor heat
exchanger is –20°C or lower continued for 2
minutes or more.
b. The counted time is 28 minutes or more, and
status that temperature of the outdoor heat
exchanger detected by the outdoor heat
exchanger is –7°C or lower and temperature
lowered by 2.5°C than the minimum value of
the outdoor heat exchanger during 10 to
15 minutes count time continued for 2
minutes or more.
c. The counted time is 34 minutes or more, and
status that temperature of the outdoor heat
exchanger detected by the outdoor heat
exchanger is -5°C or lower and temperature
lowered by 3.0°C than the minimum value of
the outdoor heat exchanger during 10 to
15 minutes count time continued for 2
minutes or more.
d. If the following three conditions are satisfied,
defrost operation (Timer defrost) starts after
heating operation for 37 minutes.
1
Setting on remote control, HEAT ( )
(mode), HIGH
(Fan), 30°C
(temperature
).
2
Room temperature is 19°C to 24°C, and
outside air temperature is 5°C or lower.
3
Defrost operation has been already
performed once.
TO
7.1A
7.1A
7.1A
16.0
15.5
11.0
10.5
Outside air temp
. (
°
C)
