Mitsubishi Electric MS-09SN-C1 Service Manual page 28

1. Indoor fan speed control
Indoor fan speed control is as same as COOL mode of "I FEEL CONTROL".(Refer to 8-1-1. COOL mode of I FEEL CON-
TROL" 1.)
2. Coil frost prevention
Coil frost prevention is as same as COOL mode of "I FEEL CONTROL".(Refer to 8-1-1. COOL mode of I FEEL CONTROL"
2.)
8-3. DRY ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a
beep tone.
(2) Select DRY mode with the OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right chart.
DRY operation will not function when the room temperature is 13°C
or below.
(4) When DRY operation functions the fan speed is lower than cool
operation expect at (fan speed) Low notch.
1. Indoor fan speed control
Indoor fan speed control is as same as DRY mode of "I FEEL CON-
TROL".(Refer to 8-1-2. DRY mode of I FEEL CONTROL" 1.)
2. The operation of the compressor and indoor / outdoor fan
The operation of the compressor and indoor / outdoor fan is as same
as DRY mode of "I FEEL CONTROL".(Refer to 8-1-2. DRY mode of
I FEEL CONTROL" 2.)
3. Coil frost prevention
Coil frost prevention is as same as DRY mode of "I FEEL CONTROL".(Refer to 8-1-2. DRY mode of I FEEL CONTROL" 3.)
8-4. FAN ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select FAN mode with the OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low.
Only indoor fan operates.
Outdoor unit does not operate.
8-5. FAN MOTOR CONTROL
(1) Rotational frequency feedback control
The indoor fan motor is equipped with a rotational frequency sensor, and outputs signal to the microprocessor to feedback
the rotational frequency. Comparing the current rotational frequency with the target rotational frequency (High, Med., Low),
the microprocessor controls SR141 (MS-09/10SN) IC141 (MS-12/15/17/18/24SN) and adjusts fan motor electric current to
make the current rotational frequency close to the target rotational frequency. With this control, when the fan speed is
switched, the rotational frequency changes smoothly.
(2) Fan motor lock-up protection
When the rotational frequency feedback signal is not output for 12 seconds, (or when the microprocessor cannot detect
the signal for 12 seconds) the fan motor is regarded locked-up. Then the electric current to the fan motor is shut off. 3 min-
utes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION INDICA-
TOR lamp flashes on and off to show the fan motor abnormality. (Refer to page 35.)
8-6. AUTO VANE OPERATION
(1) Vane motor drive
These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approx. 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode changes as follows by pressing the VANE CONTROL button.
High
Med.
Low
28
Set temperature and
:
initial room temperature in dry mode
35
30
25
20
15
10
10 15 20
Initial room temperature
High
Time
25 30 35 :