– 30 –
8-1-4. Prevent-Freezing Control
The indoor heat exchanger sensor detects refriger-
ant vapor temperature in COOL/DRY operation. If
the temperature is below the specified value, com-
pressor motor speed is reduced so that operation is
performed in temperature below the specified value
to prevent-freezing of indoor heat exchanger.
8-1-5. P. M. V. (Pulse Modulating Valve)
Using P.M.V., refrigerant flow of refrigeration cycle is
varied for the optimum temperature. Controlling
each unit separately by two P.M.V. corresponds to
difference of pipe length, fan speed, and unit tem-
perature.
If an error occurs on cycle temperature when power
source of the air conditioner has been turned on,
and if start/stop times of the outdoor unit are 30
times, move the valve once until it hits on the
stopper for positioning of the valve. In this case,
ticktack sound may be heard.
8-1-6. Louver Control
(1) Vertical air flow louvers
Positions of vertical air flow louvers are auto-
matically controlled according to the operation
status (AUTO, COOL, DRY, HEAT). Besides,
positions of vertical air flow louvers can be
arbitrarily set by pressing the [SET] button. The
louver position which has been set by the [SET]
button is stored in microcomputer, and the louver
is automatically set at the stored position in the
next operation.
(2) Swing
If the [AUTO] button is pressed during running
operation, vertical air flow louvers start swinging.
When the [AUTO] button is pressed again,
swinging stops.
8-1-7. Indoor Fan Control (DC Fan Motor)
The indoor fan is operated by motor speed non-step
variable DC drive system motor. For flow rate, motor
speed is controlled manually in three steps (LOW,
MED, HIGH), and with the unit of 10 rpm from upper
limit to lower limit in AUTO mode as described in
Table 8-1-2. It is not selected by relay, so selecting
sound does not generate.
Table 8-1-2
Operation
Fan
M10
M13
Motor speed
Air flow rate
Motor speed
Air flow rate
mode
mode
(rpm)
(m³/h)
(rpm)
(m³/h)
H
1100
470
1200
520
COOL
M
1010
440
1140
470
L
910
380
1050
380
DRY
—
810
320
820
330
H
1200
520
1280
560
HEAT
M
1100
470
1100
470
L
930
390
930
390
